Stars Traveling Close To Light Speed Could Spread Life Through the Universe

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Stars Traveling Close To Light Speed Could Spread Life Through the Universe

Posted by samzenpus on Monday December 1, 2014 @06:58AM from the starry-life-seed dept.

KentuckyFC writes Stars in the Milky Way typically travel at a few hundred kilometers per second relative to their peers. But in recent years, astronomers have found a dozen or so "hypervelocity stars" traveling at up to 1000 kilometers per second, fast enough to escape our galaxy entirely. And they have observed stars orbiting the supermassive black hole at the center of the galaxy traveling at least an order of magnitude faster than this, albeit while gravitationally bound. Now a pair of astrophysicists have discovered a mechanism that would free these stars, sending them rocketing into intergalactic space at speeds in excess of 100,000 kilometers per second. That's more than a third of the speed of light. They calculate that there should be about 100,000 of these stars in every cubic gigaparsec of space and that the next generation of space telescopes will be sensitive to spot them. That's interesting because these stars will be cosmological messengers that can tell us about the conditions in other parts of the universe when they formed. And because these stars can travel across much of the observable universe throughout their lifetimes, they could also be responsible for spreading life throughout the cosmos.

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Anyone for a game of pool? by Ded+Bob · 2014-12-01 07:07 · Score: 4, Funny

The stakes are stellar.
1. Re: Anyone for a game of pool? by Anonymous Coward · 2014-12-01 10:27 · Score: 0
  
  Where's my _car_ analogy, dammit?
2. Re:Anyone for a game of pool? by TropicalCoder · 2014-12-01 19:41 · Score: 1
  
  Seriously, what if one of these stars smashed into another similar one headed right for it at relativistic speed? It would be like the Large Hadron Collider at astronomical scale. Maybe it would create a star made of Higg's Bosons or who knows what. Maybe the resulting collision would create a Black Hole so dense it would suck in the entire Universe.
  Then I had another, totally different thought. Suppose one of these happened to be passing by... You could send a space ship at normal velocity up to meet it in such a way it gets captured by the gravity of the star and gets pulled along with it. Of course, you might experience some pretty wicked acceleration that could leave you a puddle of red goo on the deck, but that's the chance you might take.. Alternatively, get it to fling you in whatever direction you want to go via the slingshot effect. You should be able to pick up a relativistic velocity from it for free. Maybe that was what the author meant when he suggest it could seed life in other galaxies.
3. Re:Anyone for a game of pool? by Anonymous Coward · 2014-12-02 02:39 · Score: 0
  
  Might well be our ticket out of this neighborhood...
4. Re:Anyone for a game of pool? by Anonymous Coward · 2014-12-02 03:06 · Score: 0
  
  You could send a space ship at normal velocity up to meet it in such a way it gets captured by the gravity of the star and gets pulled along with it.
  
  Gravity doesn't work that way, and with just another fast passing body, you could not be captured into orbit without a third body involved or using some non-gravitational force (engines, aerobraking, etc.).
  
  Alternatively, get it to fling you in whatever direction you want to go via the slingshot effect.
  
  Direction of a slingshot would be limited, depending on what velocity you are trying to get. To get a maximal boost, you would need to be going in the same or opposite direction as the object relative to a background system. Similar to how you can't be captured by a single gravitational body, you can't slingshot off of one, and it is a three-body problem, and would depend on how the star's movement relates to the galaxy.
5. Re:Anyone for a game of pool? by david_thornley · 2014-12-02 05:03 · Score: 1
  
  A space ship will not get captured by the gravity of the star. At 0.3C, we're not getting significant relativistic effects, so it will attract just like a star would. This means that the acceleration (which isn't going to mash or spaghettify anything) is going to be just the same as what you'd get from an ordinary star, although not for long. At 0.3C, it won't be around all that long to transfer anything, and since the spaceship is pretty much motionless compared to the star it's going to attract the ship both coming and going, meaning that there will be little effect.
  Two stars moving 0.3c in opposite directions relative to us are going to collide at about 0.6C. Again, we're not getting major relativistic effects, so it's not going to be much different in total mass-energy from two stars colliding at lower speeds. No black hole. The speed of collision is much, much less than that in any serious particle accelerator, so it's not going to give us a lot of weird quantum effects.
  
  --
  "When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
6. Re:Anyone for a game of pool? by TropicalCoder · 2014-12-02 06:00 · Score: 1
  
  As far as capture goes, I think it depends how close to the star you come. Remember, a start has a massive gravity, independent of its speed. Its mass is also increased in some proportion to its velocity. Not sure how much that would contribute to its gravity.
  "Two stars moving 0.3c in opposite directions relative to us are going to collide at about 0.6C. Again, we're not getting major relativistic effects" The products of the collision do not depend on "relativistic effects", rather, they depend on temperate/energy produced by the collision. I am sure that temperature would be high enough to produce many exotic particles.
  In short, it wouldn't dismiss either of my conjectures, except to say my stated results of a collision are fanciful, but it think it would be far more dramatic than a normal collision. Think of all the energy that would be released!.
7. Re:Anyone for a game of pool? by Anonymous Coward · 2014-12-02 06:50 · Score: 0
  
  . Its mass is also increased in some proportion to its velocity.
  It is not in proportion to its velocity, it is a more complicated function: 1/sqrt(1-v^2/c^2). At 0.3c, you're talking about less than five percent. You could double that to 0.6c and still only have a 25% effect.
  
  Remember, a start has a massive gravity, independent of its speed
  And for any source of gravity short of something like a black hole, an approach from a long ways away means you will be in a hyperbolic orbit. Conservation of energy means all the energy you gain from falling into the gravitational well will be converted to kinetic energy, which will cause you to escape back out to a distance similar to your starting point. You would need to get rid of a lot of momentum in the star's frame (or find a way to gain a lot in your starting frame) to convert your approach into a trapped orbit. Unless you get close enough to the star to experience a large amount of drag from the material near the star, or very carefully exchange a lot of momentum by slingshoting off of something in orbit around the star, you would need massive engines that would have gotten you to a speed comparable to the star's on their own.
8. Re:Anyone for a game of pool? by Anonymous Coward · 2014-12-02 08:10 · Score: 0
  
  That would create quit a big bang
9. Re:Anyone for a game of pool? by david_thornley · 2014-12-03 03:55 · Score: 1
  
  Stars do have massive gravity. However, solar escape velocity from Earth's orbit is about 42 km/s. If there was a spaceship at one AU from the Sun, and the velocity difference was over 42 km/s, it would escape from the Sun. You can get closer to the Sun, but escape velocity doesn't go up that fast as you get closer, so it's about 84 km/s at 0.25 AU. So, assuming you could teleport your spaceship wherever you wanted, it couldn't possibly be close enough for 0.3 C escape velocity. If it hit the fast-moving star, its components would be accelerated accordingly, but that's not real useful.
  Relativity absolutely plays a part with your question about forming a black hole. The answer is that the kinetic energy of the stars has an equivalent mass that's small compared to the mass of the stars, so except for edge conditions we can ignore it. Temperature...that gets complicated. Somebody could calculate the increase in temperature of the whole two stars, but locally it could get much higher.
  
  --
  "When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
10. Re:Anyone for a game of pool? by TropicalCoder · 2014-12-03 05:25 · Score: 1
  
  I think I can defeat my own speculation even better...
  What I was first thinking when all this began, was this: Imagine launching a space ship made of "unobtainium" from Earth towards our sun, such that it is intended to come so close it almost grazes the sun's corona. Then it will build up tremendous velocity during its journey and shoot off at an astonishing speed as it rounds the sun.
  However, imagining that same space ship as it approaches a rogue star travelling at relativistic velocity does not mean my space ship will accelerate to relativistic velocity as it approaches the star, because I was missing a key ingredient - Time. Acceleration due to gravity involves a constant times T squared, ie: totally depends on how long a body is subjected to the influence of gravity. As my ship approaches that rogue start, the star has passed by in the blink of an eye, and my ship will have, in the end, experienced acceleration due to the star's gravity for only a brief moment - not long enough result in any appreciable acceleration.
  As to my second conjecture, there is no doubt that the collision of two stars traveling at tremendous speeds would easily result at least in the formation of a Black Hole, but beyond that, and depending on their mass, who knows what else?
11. Re:Anyone for a game of pool? by Anonymous Coward · 2014-12-03 09:06 · Score: 0
  
  Imagine launching a space ship made of "unobtainium" from Earth towards our sun, such that it is intended to come so close it almost grazes the sun's corona.
  
  Heck, imagine it just scraping the photosphere, and you could gain 600 km/s in speed if falling from a distance of 1 AU to the photosphere (would require removing the ~30 km/s orbital velocity of something launched from Earth). The problem is that as soon as you come back out to a distance of 1 AU, you will have lost all that speed you gained. That speed doesn't help you escape from the solar system or go anywhere other than the new orbit you've put yourself in.
  
  Acceleration due to gravity involves a constant times T squared,
  
  Acceleration due to gravity is not constant outside of the special case of small things on the surface of a planet. The acceleration due to gravity in space needs to be done in the full 1/r^2, although you can save yourself the calculus and just do things in therms of energy conservation. You still get less net acceleration, and for approaching something like the sun at 0.3 c you end up gaining only about 2 km/s going from 1 AU away to the photosphere, but that is moot as you will lose all of that speed on after swinging around the star.
  
  As to my second conjecture, there is no doubt that the collision of two stars traveling at tremendous speeds would easily result at least in the formation of a Black Hole, but beyond that, and depending on their mass, who knows what else?
  A collision won't even come close to causing either star to fit within its Schwarzschild radius, even taking into account the doubled mass (the speeds involved don't add much more mass beyond that. You would have the exact opposite problem, with gas and reactions being too hot, and it would blow away lots of gas. Stars collapse into a black hole when the reactions inside them slow down too much and don't produce enough heat to keep them inflated in a sense. Adding more heat and fuel makes them bigger. This is to the point that the Hayashi limit prevents stars from above a certain size even forming, as the heat from fusion would blow away gas. And that limit is for a long time scale, on a short time scale it is even easier to blow away gas from higher temperatures if a star is heated up from an outside source.
12. Re:Anyone for a game of pool? by RockDoctor · 2014-12-03 17:08 · Score: 1
  
  Maybe the resulting collision would create a Black Hole so dense it would suck in the entire Universe.
  Why would it create a particularly dense black hole. Larger black holes are less dense than smaller ones, so if you want to find a particularly dense one, you need to look for "cosmological" black holes, not ones formed by stellar collapse.
  We have plenty of supermassive black holes in galaxy cores. They haven't eaten the universe yet. So we don't need to worry about your scenario.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
13. Re:Anyone for a game of pool? by PingPongBoy · 2014-12-04 02:35 · Score: 1
  
  Forget about it! A star traveling now at a high fraction of light speed once upon a time wasn't going that fast, so even if it brings its planets in tow, it was accelerated enough to mash everything.
  But if you want to travel in style, get on a planet and gradually move the star into the path and speed you need.
  
  --
  Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
Best and fastest by Anonymous Coward · 2014-12-01 07:08 · Score: 0

Hmmm - cosmological messenger, 1/3 light speed, spreading life wherever they go. Sort of a Swiss Army star. It slices, it dices, it makes Julienne fries.
1. Re:Best and fastest by mythosaz · 2014-12-01 07:56 · Score: 0
  
  Those stars are stationary.
  We're moving at a third of the speed of light.
2. Re:Best and fastest by Anonymous Coward · 2014-12-01 08:02 · Score: 0
  
  Those stars are stationary.
  We're moving at a third of the speed of light.
  So much for others accusing me of "being slow".....
3. Re:Best and fastest by OakDragon · 2014-12-01 10:21 · Score: 1
  
  Those stars are stationary.
  We're moving at a third of the speed of light.
  No wonder I'm so tired all the time.
  
  --
  Dark Reflection
4. Re:Best and fastest by meerling · 2014-12-01 10:42 · Score: 1
  
  Is that way the day seems to drag on?
Cubic gigaparsec ... by Mostly+a+lurker · 2014-12-01 07:11 · Score: 4, Funny

Ummm, how many Olympic sized swimming pools is that?
1. Re:Cubic gigaparsec ... by Anonymous Coward · 2014-12-01 07:16 · Score: 0
  
  A metric buttload.
2. Re:Cubic gigaparsec ... by Anonymous Coward · 2014-12-01 07:17 · Score: 2, Informative
  
  http://www.wolframalpha.com/input/?i=number+of+olympic+swimming+pools+in+a+cubic+gigapasec
  1.2×10^73
3. Re: Cubic gigaparsec ... by AA1 · 2014-12-01 07:19 · Score: 5, Informative
  
  (2.93799895 Ã-- 10^79) liters in cubic gigaparsec divided by about 2.5 million liters per Olympic pool, so roughly 1.1751996e+73 pools.
4. Re:Cubic gigaparsec ... by colin_young · 2014-12-01 07:19 · Score: 2
  
  7.8e72, give or take a few.
5. Re:Cubic gigaparsec ... by Anonymous Coward · 2014-12-01 07:21 · Score: 0
  
  1 cubic parsec is (according to Google) 2.93799895 × 10^49 cubic meters. 1 Olympic-size swimming pool has 2500 cubic meters of volume.
  
  Diving, that gives 1.1751996 x 10^46 Olympic-size swimming pools.
6. Re:Cubic gigaparsec ... by RelaxedTension · 2014-12-01 07:30 · Score: 5, Funny
  
  With these kind of huge sizes, I think it's more like a gigabuttload, or as the layman would say, a Kardashian.
7. Re:Cubic gigaparsec ... by Fire_Wraith · 2014-12-01 07:35 · Score: 1
  
  It's roughly 83 Cubic Kessel Runs by the Millenium Falcon.
8. Re:Cubic gigaparsec ... by Anonymous Coward · 2014-12-01 07:37 · Score: 0
  
  I'm not sure, but it's at least 15 Kessel runs!
9. Re:Cubic gigaparsec ... by aurum42 · 2014-12-01 07:41 · Score: 2
  
  1 cubic parsec is (according to Google) 2.93799895 × 10^49 cubic meters. 1 Olympic-size swimming pool has 2500 cubic meters of volume. Diving, that gives 1.1751996 x 10^46 Olympic-size swimming pools.
  Cubic *giga*parsec, so presumably you're off by a factor of 1e27. But what's 1e27 Olympic pools between friends...
  
  --
  "The slave who knows his master's will and does not get ready...will be be beaten with many blows."Luke 12:47-48
10. Re:Cubic gigaparsec ... by Fire_Wraith · 2014-12-01 07:51 · Score: 1
  
  Woops, I need to check my math. I'm off by a factor of roughly seven figures there...
11. Re:Cubic gigaparsec ... by bill.e.gloat · 2014-12-01 08:57 · Score: 1
  
  A lot, I think.... http://www.wolframalpha.com/in...
12. Re: Cubic gigaparsec ... by buchner.johannes · 2014-12-01 09:05 · Score: 4, Informative
  
  Unfortunately, space is not Euclidean on giga-parsec scales. Here, when talking about 5000 Gpc, they refer to a "comoving scale". That is a scale where the expansion of the universe has been divided out, so that e.g. the same number of galaxies remain in this box. So if you would place the atoms of the number of swimming pools you computed in the volume, they would be twice as dense at the largest distances, where the Universe was half the current size. Also, the largest distance within a 5000 Gpc^3 is 3200 Gpc (space is not Euclidean).
  
  --
  NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
13. Re: Cubic gigaparsec ... by KiloByte · 2014-12-01 10:14 · Score: 1
  
  3200 Gpc? Er... how's that possible in a ball of radius 14.3Gpc (4.2Gpc before counting expansion)? Unless you lost ^3 somewhere.
  
  --
  The creatures outside looked from Alt-Right to Antifa; but already it was impossible to say which was which.
14. Re:Cubic gigaparsec ... by Anonymous Coward · 2014-12-01 10:26 · Score: 0
  
  http://www.wolframalpha.com/input/?i=number+of+olympic+swimming+pools+in+a+cubic+gigapasec
  1.2×10^73
  That's an astronomical number.
15. Re:Cubic gigaparsec ... by meerling · 2014-12-01 10:43 · Score: 1
  
  You get a gold star for that reply :P
16. Re:Cubic gigaparsec ... by Anonymous Coward · 2014-12-01 11:48 · Score: 0
  
  No! You don't get to just brush this off! These are *my* 10^27 Olympic pools, and I want them in my yard by noon tomorrow! Or ... or... I'll get my engineers to invent a combustible swimming pool...! etc
17. Re:Cubic gigaparsec ... by John+Allsup · 2014-12-01 12:01 · Score: 1
  
  See http://www.wolframalpha.com/in...
  
  --
  John_Chalisque
18. Re:Cubic gigaparsec ... by Anonymous Coward · 2014-12-01 15:16 · Score: 0
  
  I wish scores could exceed a 5.. I LMAO for 2 minutes straight. 1 gigabuttload = 1 Kardasian OMG....
19. Re:Cubic gigaparsec ... by Xyrus · 2014-12-01 17:51 · Score: 1
  
  With these kind of huge sizes, I think it's more like a gigabuttload, or as the layman would say, a Kardashian.
  The Kardashian is an antiquated measurement. The Minaj is the new international measurement, equivalent to roughly 10 Kardashians.
  
  --
  ~X~
Mothership by Anonymous Coward · 2014-12-01 07:12 · Score: 0

Sun Ra and George Clinton had it right all along...
I don't understand this ... by ColdWetDog · 2014-12-01 07:14 · Score: 4, Insightful

OK, if we find a hypervelocity star and we do spectrographic analysis, etc - that can help us determine if our galaxy is similar or different from others. That's obviously neat and important.
The bit of 'spreading life' doesn't make sense. Are these stars dragging a solar system (which might have living organisms) around with them? Is there some postulate that life comes from giant nuclear fusion balls?
Aliens?

--
Faster! Faster! Faster would be better!
1. Re:I don't understand this ... by khasim · 2014-12-01 07:20 · Score: 4, Informative
  
  The bit of 'spreading life' doesn't make sense.
  That's what I thought, also. Even if they were dragging planets with them (is it possible for planets to orbit that fast?) wouldn't the planets have been sterilized by the conditions at the center of whatever galaxies they came from?
  Just finding one of them should be cool enough. There's no need to postulate about "life".
2. Re:I don't understand this ... by fuzzyfuzzyfungus · 2014-12-01 07:24 · Score: 2
  
  I imagine that, in principle, a solar system could form happily enough in the inertial frame of a star moving like a bat out of hell, so long as all the necessary ingredients and resulting planets were as well.
  
  I would be a bit curious about how livable such planets would be. Space is pretty empty; but not entirely so; and if you are travelling at those sorts of speeds relative to the almost-nothing, you'll be running into hydrogen atoms and dust specks and things fast enough that the experience will be somewhat akin to standing downrange of a particle accelerator. That's the sort of thing that might not leave a planet without seriously heroic gravity or quite a magnetic field without much atmosphere.
3. Re:I don't understand this ... by Anonymous Coward · 2014-12-01 07:37 · Score: 4, Interesting
  
  The stars' velocity relative to the bulk of matter in our galaxy doesn't change anything within its own frame of reference. It can have a perfectly happy solar system just like ours. Now - whether or not such a solar system was likely to form in the environment that flung that star out so quickly is another matter entirely, but assuming that if formed somehow, there is nothing keeping it from being stable like our solar system - until some of that hyper-velocity interstellar dust zips through and sand-blasts the bejesus out of everything.
  It would be an interesting form of "intergalactic bus" to hitch a ride on a passing star, orbit it and use its radiation (and that of the passing dust) to sustain a ship until you get wherever you're interested in going.
4. Re:I don't understand this ... by Zocalo · 2014-12-01 07:45 · Score: 3, Insightful
  
  It's not just the radiation levels in a galactic core or the overall velocity of the star system that bothers me, we're also quite a way into the territory or relativistic speeds here so there could also be some very odd effects at different points in a planet's orbit depending on the inclination of the orbital plane to the overall direction of motion. It seems like an awfully big strech to expect even the most primitive forms of life to be able to start under those conditions, let alone survive the trip. That badly needs a justification that the paper fails to provide, unless you count a throwaway line and a couple of references, neither of which look like the would explain how life might exist under those conditions.
  
  --
  UNIX? They're not even circumcised! Savages!
5. Re:I don't understand this ... by CaptainLard · 2014-12-01 07:45 · Score: 1
  
  Just a guess here...
  Take it back a step. Say one galaxy is super dense and has lots of supernovas. It's stars would be full of heavier elements essential for life. If one of these stars gets flung into a diffuse galaxy and gets captured it would be providing the elements that are unlikely to form on their own in that area. Eventually it would burn up and provide the basis for a new solar system so no need to BYOPlanets! It would seem the odds are small but the universe is a big place...
6. Re:I don't understand this ... by wierd_w · 2014-12-01 07:52 · Score: 1
  
  Such stars should be able to have planets orbiting them, since the frame of motion is relative to the star, not the rest of the universe.
  Frame dragging is totally a thing.
  The more interesting thing, is that for such stars, should they have planetary systems, time will be much slower for them than for the rest of the universe, due to their high velocity relative to the universe. This means that they may be billions of years old by our reckoning, but only millions of years old by their reckoning.
  I think the idea is for panspermia to have a radical vehicle of transport here. Biosphere containing planets are blasting off into the universe, bound to stars that are traveling at a significant fraction of C, and asteroids hitting said planets, knocking bits of rock laced with microbes into said solar system, and getting ejected, would drop a trail of microbe laced breadcrumbs all over the universe.
  More interesting (to me at least) would be what the night sky would look like to such an object. Traveling at such a velocity, the sky would be different each and every night.
7. Re:I don't understand this ... by angel'o'sphere · 2014-12-01 07:53 · Score: 1
  
  You seem to forget the newton laws and the star only travels around 1/3rd of light speed. Planetary live is not at all effected, it does not notice the fast movement as the reference point is the sun around they orbit.
  However, how such a system should spread live is beyond me.
  
  --
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8. Re:I don't understand this ... by Anonymous Coward · 2014-12-01 07:55 · Score: 0
  
  OK, if we find a hypervelocity star and we do spectrographic analysis, etc - that can help us determine if our galaxy is similar or different from others. That's obviously neat and important.
  The bit of 'spreading life' doesn't make sense. Are these stars dragging a solar system (which might have living organisms) around with them? Is there some postulate that life comes from giant nuclear fusion balls?
  Aliens?
  Not just aliens... Ancient Aliens
9. Re:I don't understand this ... by TWX · 2014-12-01 08:06 · Score: 1
  
  XKCD had a comic about playing kerbal space program and using the sun to slingshot a probe with a gravity-assist. It would have fried the probe. I expect that a planet in the galactic core would be equally fried.
  
  --
  Do not look into laser with remaining eye.
10. Re:I don't understand this ... by Rashdot · 2014-12-01 08:15 · Score: 1
  
  TFA says, they can spread life "beyond the boundaries of their host galaxies"
  
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  This is not the sig you're looking for.
11. Re:I don't understand this ... by dreamchaser · 2014-12-01 08:17 · Score: 2
  
  While I suppose it's possible, I find it highly unlikely that any planet forming in the environment of a supermassive black hole (amounts of radiation we can't even really fathom) would be anything but sterile.
12. Re:I don't understand this ... by CrimsonAvenger · 2014-12-01 08:21 · Score: 1
  
  The more interesting thing, is that for such stars, should they have planetary systems, time will be much slower for them than for the rest of the universe, due to their high velocity relative to the universe.
  Umm, no.
  0.333c give you a time dilation factor of 0.943. So for every century that passes here, 94 years and a few months will pass there.
  As seen from here, of course.
  As seen from there, for every century that passes, 94 years and a few months will pass here. Ain't relativity grand?
  
  --
  
  "I do not agree with what you say, but I will defend to the death your right to say it"
13. Re:I don't understand this ... by Immerman · 2014-12-01 08:22 · Score: 4, Informative
  
  Relativistic effects are a non-issue because there is no preferred reference frame in the universe. Our own sun is at this very moment moving at 99.9999999% of lightspeed, when observed from the appropriate position. When observed from there the relativistic effects are quite profound, but the beauty of relativistic effects is that their existence is entirely dependent upon the observer's frame of reference - a thousand different observers on a thousand different relativistic trajectories will see a thousand different sets of relativistic effects on us, and yet we, in a more local frame of reference see virtually none. And every one of those thousands of different observations are all mathematically equivalent.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
14. Re:I don't understand this ... by Anonymous Coward · 2014-12-01 08:42 · Score: 0
  
  Frame dragging is totally a thing.
  Yes it is, but has to do with being near rotating massive bodies and is unrelated to the idea that a constant velocity change is still an inertial frame.
  
  More interesting (to me at least) would be what the night sky would look like to such an object. Traveling at such a velocity, the sky would be different each and every night.
  Short of the planet having a very long day, the sky wouldn't change much just because of how big distances are in space. Assuming you had another star about 3 light years away, it would only move about 1 arcminute a day at a third of c. This is 1/30th of the diameter of the moon, and wouldn't be noticed without another near by visual reference, and even then is about the limit of 20/20 vision. On a month by month timescale you could see changes assuming there are stars near by, although if you are in a more empty area, it might be longer than that for visual changes to happen.
15. Re:I don't understand this ... by Immerman · 2014-12-01 08:47 · Score: 4, Interesting
  
  >You seem to forget the newton laws and the star only travels around 1/3rd of light speed
  Relative to what, the galactic core? Why is that special, it's just an arbitrary point in space? Remember, relativity means everything in the universe is moving at 99.9999999999999999999999999% of light speed, when seen from the right inertial reference frame.
  As for how they could spread life - that should be obvious. If there's life on a planet around the star, something will probably survive the still-ridiculously-long journey across intergalactic space, the only plausible way anything could. That would afford sufficiently patient intelligent species a vehicle to travel to new galaxies, as well as performing non-sentient panspermia on an intergalactic scale. And as it passes through a new galaxy that planet is going to be sandblasted by the interstellar medium, leaving a wake of life-bearing ejecta behind it. And given the rogue star's highly atypical path a lot of stars will very quickly pass through that cloud, depositing that life on their own planets, where it could potentially take root. And conversely, if it passes near a life-bearing normal star, that same "sandblasting" will be depositing any lifebearing ejecta on its planets, giving even lifeless worlds a chance of hosting vibrant ecologies by the time the next galaxy is encountered.
  Due to the relative velocities involved it actually requires life to survive far less time space than in a traditional interstellar panspermia scenario, though the odds of a successful "seeding" are probably still lower than in a merely interplanetary seeding within the same star system - which is beginning to seem almost inevitable with what we know of the physics of asteroid impacts and various organisms' ability to survive in space (to say nothing of DNA and RNA, which don't necessarily need the host organism to reproduce)
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
16. Re:I don't understand this ... by RabidReindeer · 2014-12-01 08:47 · Score: 2
  
  tl;dr version:
  Time dilation is a hyperbolic curve. The fun stuff doesn't start showing up until you get VERY near the speed of light.
  For the math purists, forgive me if "hyperbolic" is the wrong term. The active ingredient is something like 1/(c**2 - v**2)
17. Re:I don't understand this ... by Waffle+Iron · 2014-12-01 08:49 · Score: 1
  
  I can maybe see the life evolving in one of these solar systems after it leaves the black hole area, presuming the atmospheres of planets aren't scoured away by high-speed interactions with the interstellar medium.
  However, how could this life "spread"? I don't see how you slow down any complex molecules from these speeds without totally incinerating them.
18. Re:I don't understand this ... by Anonymous Coward · 2014-12-01 08:54 · Score: 0
  
  Such stars should be able to have planets orbiting them, since the frame of motion is relative to the star, not the rest of the universe.
  Um, no. Planets orbiting the star when it goes into orbit around a black hole and then gets ejected from that orbit would almost certainly be ripped away from the planet by the difference in gravity field strength between the star and the position of the planet in orbit around the star. The planet would also become super heated by gravitational tidal forces and bombarded by very high energy radiation. Not only would life on the planet likely not survive, the planet itself would likely not survive.
  Frame dragging is a thing, but even an engineer should know better than neglect the influence of a black hole on things when in proximity to it.
19. Re:I don't understand this ... by Anonymous Coward · 2014-12-01 09:01 · Score: 0
  
  If accelerated in a very nice uniform straight line kind of way. When accelerated by proximity to black hole however the accretion disk of a newly formed star would be ripped away as would any planets that had already formed. After that a solar system could not form.
  1/3C is not fast enough to significantly change the energy of EM radiation and particles from outside its frame of reference.
20. Re:I don't understand this ... by catmistake · 2014-12-01 09:04 · Score: 1
  
  Are these stars dragging a solar system (which might have living organisms) around with them?
  
  Entourage! Fanatics! Paparazzi! Yes, they follow the stars, but I'm not sure its necessarily "life."
  
  --
  The Admin and the Engineer
21. Re:I don't understand this ... by Hognoxious · 2014-12-01 09:11 · Score: 2
  
  At least while they were there.
  Then again, at the speeds these buggers are moving, they've only been free of the black hole shit for about three minutes.
  But you know what they say: you can take the star out of the environment of a supermassive black hole but you can't take the environment of a supermassive black hole out of the star.
  
  --
  Confucius say, "Find worm in apple - bad. Find half a worm - worse."
22. Re:I don't understand this ... by careysub · 2014-12-01 09:12 · Score: 4, Informative
  
  Answers to various comments/questions on this sub-thread:
  Time dilation at 1/3 c is 5.7%, quite a noticeable amount, but not remotely close to to turning billions of years into millions.
  Tidal effects are small for super-massive galactic black holes. I doubt tidal disruption of Earth-like (i.e. fairly close) orbits would occur, especially for cool M-type stars (the most common kind).
  While individual particles of cosmic dust hitting the planet at 1/3 c won't be a problem, (they will simply explode high in the upper atmosphere), the energy flux hitting the atmosphere from interstellar gas would be considerable. Average interstellar space has something like 1,000,000 hydrogen atoms per cubic meter. At 100,000 km/sec every second there would be 100,000*1,000*1,000,000= 10^14 hydrogen atoms hitting each square meter of atmosphere. The kinetic energy of those atoms would be about 1000 J, so roughly 1000 watts/m^2 of heating from interstellar hydrogen. Earth gets 1400 watts/M^2 of heat from the Sun, so it would roughly double the heating of an Earth-like world until it cleared the galaxy plane. If it ran into a denser patch (all of the region in the galactic center would be denser than the average I quoted) then the heating could be 10, 100, even 1000 times higher for a bit. I think this would cook any existing Earth-like planet.
  Once in interstellar space though the heat load would drop by a factor of 10,000 to 100,000 of the average interstellar value and would cease to be significant. From there on the planet and star system would evolve on their own, and a new biosphere could come into existence.
  
  --
  Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
23. Re:I don't understand this ... by Immerman · 2014-12-01 09:18 · Score: 1
  
  Don't you mean time will be much slower for the rest of the universe, which is zooming by at close to light speed while the rogue star stands still? Relativity works both ways after all, and at least for non-accelerating motion the effects are basically entirely observer-dependent.
  The sky would only change much while passing through a galaxy, and even then not all thatquickly. Consider - even traveling at 99% lightspeed, if they passed perpendicularly halfway between us and Alpha Centauri, it's only seeing our stars moving at a maximum angular speed of about (1 light year/year) / (2 light years) = 0.5 radians/year, or about 0.08 degrees per day, though relativistic angular compression would play some loopy games with that. Enough to measure easily, but you're probably not going to really notice the motion of even the closest stars from day to day.
  There are some wonderful physics-based simulations of what flying through the galaxy at (heavily time-lapsed) relativistic velocities would look like floating around the net, I'd recommend watching a few if you're interested. Shouldn't make any real difference if you're on a planet rather than a spaceship.
  Between galaxies though, where the vast majority of the star's time would be spent, they'd be treated to a relatively empty night sky featuring only a handful of almost-stationary "stars" - those few nearby galaxies still close enough to be seen.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
24. Re:I don't understand this ... by Immerman · 2014-12-01 09:24 · Score: 1
  
  Well, we're already basically standing downrange of a particle accelerator as it is - we're constantly bombarded by intergalactic high energy particles traveling at insane fractions of lightspeed. It's not going to matter much if your planet is moving at 0.9c when you get hit by something moving at 0.9999999c. We've recorded impacts of single electrons with as much mass-energy as an entire iron atom, and that's just the impacts that have hit the miniscule portion of the planet on which we have built detectors to measure them.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
25. Re:I don't understand this ... by buchner.johannes · 2014-12-01 09:31 · Score: 3, Interesting
  
  Not all supermassive black holes are actively accreting. In fact, the fraction of time their accretion disks actually output massive amounts of radiation is ~10%, on patches of ~ hundred million years timescales.
  A planetary system could form outside the center of the galaxy and travel close to the galactic center. You have to keep in mind that the distances between stars are enormous when compared to distances between planets. For example, our nearest star is 270 000 earth-sun distances (4 lightyears) away, while Jupiter is only 5 earth-sun distances from the Sun. So a "stripping" of planets, due to tidal forces, is extremely small, even when it comes close to the supermassive black hole in the center of the galaxy. It is true however that for the closest orbits, such as 120 earth-sun distances for S2 (S2 reaches speeds of 5000 km/s), this effect will be important. However, I suspect that while a single, quick swing-by will alter the orbits of planets (generally increasing ellipticity), that effect leads to the immediate destruction of the entire system. Normal planetary systems are also not stable systems. Changes in the orbits, interactions between planets, etc. are common; Only when stable oscillations are reached, the orbits remain the same for a few million years. So I suspect that the planets can re-arrange into a stable system (perhaps under ejection of one of the planets).
  I think the changes are better if the system is a newly born star, where planetoids are still forming in a thick disk of gas and dust. Then, the partially destroyed disk can re-arrange quickly and form planets after swing-by. That would not necessarily be a problem for "spreading of life", if this process occurs e.g. via comets.
  
  --
  NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
26. Re:I don't understand this ... by Immerman · 2014-12-01 09:32 · Score: 1
  
  > Is there some postulate that life comes from giant nuclear fusion balls?
  Umm, yeah, that's kind of the default assumption, isn't it? Big ball of fusion, plus orbiting rocky bits coalesced from heavier elements, plus a few other key ingredients and voila! Life maybe happens. We're not really clear on the details yet, but the only other explanation involves some timeless dude with a long white beard waving a magic wand around, so most rational people give the benefit of the doubt to the former explanation.
  There's lots of other hypotheses, such as panspermia, about the ways in which life could spread between planets and even star systems, but they only serve to increase the odds that any given planet will eventually support life, they say nothing about how life originated.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
27. Re:I don't understand this ... by BaronAaron · 2014-12-01 09:33 · Score: 2
  
  My understanding is the relative velocities between macro sized objects in the universe are rather small. Small enough where relativistic effects are minute. The article mentions 3% the speed of light being the high end. You would be hard pressed to find anything larger then a particle moving 99% the speed of light relative to our sun. Even these hyper-velocity stars are only 33-50% the speed of light.
28. Re:I don't understand this ... by Jason+Levine · 2014-12-01 09:55 · Score: 1
  
  Let's assume that a star travelling 1/3rd the speed of light had a habitable planet on it and there was life on that planet. What would moving so fast do to the stars in the sky? Would they be blurred? Would some sections of sky be darker or lighter (or redder/bluer) than others? Would the star patterns change on a regular basis?
  It might be interesting to figure this out.
  
  --
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29. Re:I don't understand this ... by xaotikdesigns · 2014-12-01 09:57 · Score: 1
  
  All that radiation? We better hope there isn't any life, because if comic books have taught me anything, it's that it would be a planet of nothing buy hulks by now.
  
  --
  XDInd
30. Re:I don't understand this ... by ultranova · 2014-12-01 09:58 · Score: 1
  
  Even if they were dragging planets with them (is it possible for planets to orbit that fast?)
  
  Fast? From the viewpoint of orbiting planets, the star is at rest and it's the rest of the universe that's moving.
  
  wouldn't the planets have been sterilized by the conditions at the center of whatever galaxies they came from?
  
  Even if they weren't, any lifeform that somehow leaves its home planet is unlikely to survive hitting another at 100,000 km/s. Unless our yellow star gives it new superpowers as plot demands, of course.
  
  --
  Forget magic. Any technology distinguishable from divine power is insufficiently advanced.
31. Re:I don't understand this ... by xaotikdesigns · 2014-12-01 10:04 · Score: 1
  
  We used those stars to guide us over the years, and while they have still moved slightly, the North Star is still to the North, and other stars are still generally in their same positions, and we can still use them the same way our ancestors did.
  Now how would this effect multiple generations of explorers on a planet orbiting a hypervelocity star?
  
  --
  XDInd
32. Re:I don't understand this ... by climb_no_fear · 2014-12-01 10:11 · Score: 1
  
  The Puppeteers are simply escaping the galactic core explosion, better hurry while there's still time
33. Re:I don't understand this ... by CaptainLard · 2014-12-01 10:22 · Score: 1
  
  Why does a whole earth of life need to form near the black hole? The star doesn't need to bring a planet full of spores with it, just an infusion of elements that may be rare in another galaxy. The alien star might then get captured and live out its life in a benign galaxy eventually becoming a nebula full of heavy elements that will become the next star/planet system. Essentially it's bringing planetary system embryos with it*.
  This thread seems caught up on the idea life being transported. Providing building blocks to a location that has none is just as good for seeding life when you have billions of years to spare*.
  *Maybe. Just an uninformed hypothesis
34. Re:I don't understand this ... by Zocalo · 2014-12-01 10:32 · Score: 1
  
  At 1/3 the speed of light you'd get noticeable blue/red shift along the axis of travel, which would probably be visibly apparent in the spectra of stars. You wouldn't get blurred stars unless they were passing by really, *really* close, but the pattern of stars would constantly change with the differences apparant over the course of a human lifespan. For instance, if we were moving at that speed and Proxima Centauri were roughly in the direction of travel, then it would go from ahead of us to a similar distance behind in the space of a couple of decades, and with an obvious before/after colour shift.
  
  Any religion and early attempts at astronomy would probably be... interesting. :)
  
  --
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35. Re:I don't understand this ... by Anonymous Coward · 2014-12-01 10:33 · Score: 0
  
  Even if the star's planets were sterile at the start of the motion, if panspermia exists then it is likely that the planets encountered interstellar spores during their travel. I say "likely" because the probability of encountering various materials is increased due to the fast motion. Unfortunately, the chances of collision is also increased... but again, so are the chances of collecting new gases/particles and forming new planets. That could be one odd solar system, with numerous vectors of motion being applied over long periods.
36. Re:I don't understand this ... by Immerman · 2014-12-01 10:53 · Score: 1
  
  And? There doesn't have to be any sort of object at all in a location for it to be a valid reference frame. Posit the existence of a point passing our galaxy at 99% light speed - that hypothetical point is a perfectly valid inertial reference frame, and you can model our entire galaxy as though you were standing on that motionless point while our galaxy zooms past at 99%c, and while far more complicated, the math still all works out the same: You can still accurately predict the path of a baseball thrown on Earth, despite the mind-numbingly intense relativistic effects.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
37. Re:I don't understand this ... by Anonymous Coward · 2014-12-01 11:23 · Score: 0
  
  Any planets orbiting these stars would be bombarded by gas and dust going at 0.33c, so they would be sterilized by the resulting radiation.
  Anything living trying to escape those planets would similarly impact their destination at 0.33c and not survive.
  Conclusion: no life to begin with, and spreading it would kill it.
38. Re:I don't understand this ... by LVSlushdat · 2014-12-01 11:29 · Score: 1
  
  These comments remind me I'm currently reading a new sci-fi novel by Larry Niven and Greg Benford, actually two novels, "Bowl of Heaven" and its sequel, "Shipstar".. Imagine a spinning bowl that had the circumferance of somewhere close to the orbit of Venus, and being propelled by plasma from the captive star thru a knot-hole in the bowl. .. THAT could truly be called a "star-drive"... The bowl has a spin for about 8/10s of a G, and has a bunch of alien species living on it.. And as close as I can tell, as the authors never actually (so far into the second book) tell you how fast the lash-up is going, the story tells of a 1/3 lightspeed colony starship from Earth that catches up to it about 1/2 way to the colony ships destination All in all, I'm about 1/2 way thru the second book and its DEFINITELY a page-turner, but then most of Niven and Benford's writings *are* page-turners...
  
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39. Re: I don't understand this ... by Anonymous Coward · 2014-12-01 12:28 · Score: 0
  
  I believe they are referring to the fact that stars churn out the basic elements and forces that are needed for life to come into being and survive. Hence Sagan's comment regarding its all being made of star stuff.
40. Re:I don't understand this ... by Ferrofluid · 2014-12-01 12:32 · Score: 1
  
  Even if they were dragging planets with them (is it possible for planets to orbit that fast?)
  Velocity is relative. If such a hypervelocity star did have a planetary system, then from the reference frame of that system, its own centre of mass would be stationary and it would be the rest of the universe that's whizzing by at relativistic speeds.
41. Re: I don't understand this ... by Anonymous Coward · 2014-12-01 12:33 · Score: 0
  
  *us*
42. Re:I don't understand this ... by flyingsquid · 2014-12-01 12:54 · Score: 3, Informative
  
  OK, first of all, let's assume that the collision of two giant galactic black holes can fling stars out of the galactic center in a way that doesn't completely destroy any planetary systems within those star systems. How on earth does life get off of such a planet onto another? If a collision in the solar system were to launch a microbe-laden rock out of the star system, it's still traveling at a third of lightspeed. How do those microbes make a safe landing? For that matter, what about the planet that those microbes land on? Chicxulub is estimated to have released 100 million megatons of explosive energy, which is equivalent to giving every man woman and child on the planet a Hiroshima nuke and detonating them all at once. Now, the Chicxulub asteroid is estimated to have traveled around 20,000 km/sec. And .3 lightspeed is 100,000,000 m/sec, or about 5,000 times the speed of the Chicxulub asteroid. Since kinetic energy scales as velocity squared, we're dealing with an impact that is 25,000 Chicxulub asteroids. So imagine wiping the dinosaurs out. And then doing it again, 24,999 times. That's 2,500,000,000,000 megatons - 2.5 trillion megatons- of explosives. Even a much smaller asteroid- say, 1 km in diameter instead of 10 km- is still going to pack far more wallop than Chicxulub did, and create an extinction event. Even a single kilogram is going to come in with as much energy as a large H-bomb. My guess is that if these stars have any effect whatsoever on the evolution of life in the universe, it's probably not a terribly constructive one...
43. Re:I don't understand this ... by Anonymous Coward · 2014-12-01 15:50 · Score: 0
  
  Which star is our north star changes on a ~25 ka cycle, with different stars having done so in the past and there being periods where there is no particular star near the north star. Life moves on though, and there are plenty of other ways to orient one self, especially when there is no visibility of the sky. And while a star close by would move a couple degrees a year, something further away, say the distance of Polaris, would only move a couple arcminutes a year. Any navigating society could adapt to that just fine, unless you get stuck not seeing the sky for years at a time.
44. Re:I don't understand this ... by Anonymous Coward · 2014-12-01 17:13 · Score: 0
  
  In cosmology there's a preferred reference frame: the one in which the universe appears isotropic. If in your reference frame galaxies appear blue in one direction and red in the opposite direction, then you are "moving".
45. Re:I don't understand this ... by Anonymous Coward · 2014-12-02 00:27 · Score: 0
  
  this seems to confuse colloquial ideas about needing infinite energy and attaining infinite mass to accelerate to C
46. Re:I don't understand this ... by Anonymous Coward · 2014-12-02 01:36 · Score: 0
  
  The bit of 'spreading life' doesn't make sense.
  That's what I thought, also. Even if they were dragging planets with them (is it possible for planets to orbit that fast?) wouldn't the planets have been sterilized by the conditions at the center of whatever galaxies they came from?
  Just finding one of them should be cool enough. There's no need to postulate about "life".
  You're forgetting that we are purely on speculation without real facts to base them on with the "spreading life" statement. From a scientific standpoint there currently is no evidence of life anywhere else in the universe, although some people like to toss out obscure ideologies to claim their are (or aren't). So if we divert our path from facts and evidence, then why cant we dream up a life form that can survive those conditions?
47. Re:I don't understand this ... by Immerman · 2014-12-02 02:29 · Score: 1
  
  And if they appear red in every direction - as is the case for anything at a distance?
  Perhaps convention states a preference, but that reference frame gets no special physical significance. After all the vast majority of the universe is (presumably) invisible, forever causally isolated from us by the ever-accelerating expansion of the universe (assuming of course that FTL isn't possible). Any "average" reference frame is by it's nature limited to that tiny fraction of the universe we can see. An observer a few billion light years in any direction would observe a very different average.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
48. Re:I don't understand this ... by david_thornley · 2014-12-02 05:13 · Score: 1
  
  Relativistic speeds relative to what? The star and planets are in their own reference frame, and we're moving at 0.3C relative to them, so any problems they'd have due to relativistic motion we'd have also. As far as relativistic speeds go, its time is passing less than 5% slower, and we see it as 4.8% more massive, so for most purposes these aren't relativistic speeds.
  
  --
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49. Re:I don't understand this ... by david_thornley · 2014-12-02 05:22 · Score: 1
  
  The problem with catching a ride is accelerating to the star's velocity in order to soft-land on the planet. Gravitational attraction isn't going to do that. Hitting the planet would, but that's not likely to leave any intelligent beings alive. If you can land on the planet and walk (or ooze, or levitate) away, it means you've already matched velocities and could just as easily have sent your spaceship. The advantage I see is that, if you can make the planet more or less inhabitable, you can expand out over it and establish a large civilization that has a prayer of surviving
  The Andromeda galaxy and ours are currently about 2.5 million light-years away, which means that this 0.3C speedster would take something over 7.5 million years to cover the distance (not considering any space expansion effects). Relativistic time and distance changes would be on the order of 5%, or lost in the noise given that we're just estimating. Now, 7.5 million years aren't much at all in geological and astrophysical time, but it's pretty long in human time. I'd be fascinated to find a civilization that old (and we aren't going to in this system).
  
  --
  "When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
50. Re:I don't understand this ... by Anonymous Coward · 2014-12-02 06:50 · Score: 0
  
  For the star to get flung out, it would need to be in at least a 3 body system, where the other 2 bodies are extremely massive. Then include a planet? How is the planet supposed to stay gravitationally bound to the star when the star is itself randomly orbiting 2 or more massive black holes? I don't know if it's impossible, but it's going to be very very unlikely.
51. Re:I don't understand this ... by Immerman · 2014-12-02 08:07 · Score: 1
  
  Sure, matching velocity is a bit of a trick, but taking a star along for the ride makes intergalactic travel at least feasible. Even if there isn't a planet you can to terraform you at least have a star to power your orbital civilization for the millions of years it takes to get to another galaxy.
  For that matter you could even accelerate an entire habitable planet into orbit around the star - it'd take a lot more resources than a space ship, but strap a mass-conversion rocket to Venus, or maybe Neptune, and you've got a gravitational "tug boat" with plenty of fuel, and it'd be many orders of magnitude easier to transfer Earth to a rogue star than to accelerate our sun to similar velocities. (Though I suppose really you'd probably want to use a red dwarf - less mass and an effectively infinite lifespan.)
  Sure, you could try to cross such vast time and distance in a well-fueled seedship instead, but then your ongoing energy budget depends on having enough fuel and keeping your technology working for millions of years, even through the nigh-inevitable repeated collapses of civilization and potential descent into barbarism. Ride along with a star though and all you're committing to is dark night skies and no interstellar voyages for a few million years. So long as you don't sabotage your planet/eco-dome's ability to support life, and don't get devoured by the intergalactic space-weasels, your species will probably survive the journey. And if they have a habitable planet along they'll be able to do so in fine style.
  
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52. Re:I don't understand this ... by cwsumner · 2014-12-03 09:43 · Score: 1
  
  Relativistic effects are a non-issue because there is no preferred reference frame in the universe. ... And every one of those thousands of different observations are all mathematically equivalent.
  That's true, except:
  If / when a cloud of dust from our rapidly passing, high speed, galaxy hits the planet, it will do just as much damage as if it were the planet or star hitting the dust cloud. Ouch!! 8-)
  Talk about bad weather.
  And I wonder, would such a star system have it's own dust clouds? And have we perhaps already been hit by one?? 8-}
Just stars or whole solar systems? by Ultra64 · 2014-12-01 07:14 · Score: 1

Do the stars drag planets along with them at those speeds?
1. Re:Just stars or whole solar systems? by dotancohen · 2014-12-01 07:17 · Score: 1
  
  Yes, that is a principal of relativity: all inertial frames are equivalent.
  
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2. Re:Just stars or whole solar systems? by magarity · 2014-12-01 07:23 · Score: 4, Interesting
  
  If they have planets, of couse. And if you could intercept and move on to one of those planets, you could observe a much longer chunk of time go by in the rest of the universe. That would be fascinating for any astronomer.
3. Re:Just stars or whole solar systems? by Anonymous Coward · 2014-12-01 07:45 · Score: 0
  
  Except that tidal forces are huge when orbiting a black hole at 0.03c, and they are probably even bigger when being ejected at 0.3c by a close encounter with a second blackhole. Those tidal forces might not be large enough to destroy the star, but they might be large enough to rip apart a solar system.
4. Re:Just stars or whole solar systems? by ZombieBraintrust · 2014-12-01 09:04 · Score: 1
  
  Its may be possible for a system to form after the star is ejected. (from captured debri and caputured exoplanets)
5. Re:Just stars or whole solar systems? by I'm+not+god+any+more · 2014-12-01 09:31 · Score: 1
  
  If they have planets, of couse. And if you could intercept and move on to one of those planets, you could observe a much longer chunk of time go by in the rest of the universe. That would be fascinating for any astronomer.
  At a third of the speed of light your time dilation would only give you a 5% increase in your time duration. So, not so fascinating. You'd be better off increasing your life span by becoming a eunuch (13.5 extra years of life) - well, maybe on second thoughts you might not be better off after all
6. Re:Just stars or whole solar systems? by xaotikdesigns · 2014-12-01 10:06 · Score: 1
  
  Captured while moving at those speeds? I'm fairly certian (from my playing around in Universe Sandbox) that a star like that wont capture anything, it will just fling stuff everywhere
  
  --
  XDInd
7. Re:Just stars or whole solar systems? by Anonymous Coward · 2014-12-01 10:16 · Score: 0
  
  If they have planets, of couse. And if you could intercept and move on to one of those planets, you could observe a much longer chunk of time go by in the rest of the universe. That would be fascinating for any astronomer.
  At a third of the speed of light your time dilation would only give you a 5% increase in your time duration. So, not so fascinating. You'd be better off increasing your life span by becoming a eunuch (13.5 extra years of life) - well, maybe on second thoughts you might not be better off after all
  Actually, time dilation works in both directions. We would see the astronomer's clock ticking slowly, and he would see our clock (and other comoving clocks) ticking slowly. So he would not observe a longer chunk of time, but a shorter chunk of time. See also: twin paradox.
8. Re:Just stars or whole solar systems? by dotancohen · 2014-12-02 01:24 · Score: 1
  
  I think that you are right. A system moving close to C will be as stable as a system stationary relative to the distant background. However, the interaction which causes such a system to accelerate to C would destroy most fragile structures, likely including most planetary orbits.
  
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9. Re:Just stars or whole solar systems? by Anonymous Coward · 2014-12-02 06:54 · Score: 0
  
  I'm wondering how the star stays together. A large enough blackhole can tear a star apart from over 1ly away. I guess given enough time and enough systems, there's bound to be a certain number that allow for these situations, no matter how rare.
Title by schneidafunk · 2014-12-01 07:19 · Score: 1

How is a third of the speed of light considered "close to the speed of light"?

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1. Re:Title by Anonymous Coward · 2014-12-01 07:28 · Score: 1
  
  Believe me, a third of the speed of light is very close to the speed of light. :)
2. Re:Title by wonkey_monkey · 2014-12-01 07:49 · Score: 1
  
  Well, how close've yoouu got, huh?
  
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3. Re:Title by Ashenkase · 2014-12-01 07:53 · Score: 1
  
  O ya sure... 1/3 the speed of light is close to the speed of light.
  
  That's like saying the 33% I got on my math exam was actually very close to 100%.
  
  If by very close you mean not close at all, then yes, you are right, 33% is very close to 100%.
4. Re:Title by crunchygranola · 2014-12-01 07:57 · Score: 3, Informative
  
  The the term used in the paper is "semi-relativistic" - fast enough that relativistic effects cannot be ignored in even routine calculations about its properties. At 1/3 the speed of light the time dilation effect amounts to a 5.7% difference for example.
  "Close to the speed of light" is the summary author's attempt to render "semi-relativistic" in sensible common place terminology.
  
  --
  Second class citizen of the New Gilded Age
5. Re:Title by Anonymous Coward · 2014-12-01 08:00 · Score: 0
  
  It's close in that Newtonian physics starts to break down. You end up with space and time dilation between reference frames. You get apparent length and time contraction, and as a result red-shifting of light.
  The rule of thumb that I was taught was anything above 10% of the speed of light you have to start using non-Newtonian physics and in certain cases you start even earlier than that. In terms of speed, 33% is a pretty significant change from speeds humans usually experience.
6. Re:Title by Anonymous Coward · 2014-12-01 08:01 · Score: 0
  
  1/3 c: A very tiny time dilation.
7. Re:Title by Yebyen · 2014-12-01 08:04 · Score: 2
  
  If you were moving at 1/3 the speed of light, you are approximately 6% shorter than you were in a rest frame. (To an outside observer? I am never sure if I have this stuff right because it's totally impossible for me to demonstrate with an experiment. For a thought experiment, inside of your frame of reference you wouldn't be able to tell because your measuring devices would experience the same transformation.)
  If you were at 2/3 the speed of light, you would be about 34.1% shorter. This is length contraction. As you approach the speed of light, it is harder and harder to accelerate (more energy input is required). If you were at 99.99% the speed of light, you would be 1/70th your current length. This is the same factor that determines how much harder it is to accelerate. It's called gamma. At normal (non-relativistic speeds) your gamma is 1.0. At 1/3 the speed of light, your gamma is about 1.06066 (so the effect of gamma is 0.06066, or roughly 6%). I am rusty but I think you could consider anything with a gamma measurably greater than 1 to be "close to the speed of light" compared to how fast we are moving on this rock, for example at 1% speed of light your gamma is only 1.00005. Our solar system moves around about 220km/s according to Google, or 0.073% the speed of light. So, gamma of 1.00000 out to at the very least least 5 digits.
  
  --
  Restating the obvious since nineteen aught five.
8. Re:Title by Anonymous Coward · 2014-12-01 08:15 · Score: 0
  
  Because it is able to traverse a significant fraction of the observable universe in the same amount of time light does. In this case such fast stars from 1/27th of the observable universe can reach us.
  It is unlikely that such a star would retain satellites through the process of being accelerated by a black hole and planet formation is an effect of star formation, so such a star wouldn't form planets after being accelerated so there is little chance for life hitching a ride.
  While we might get a better view of such stars because they are closer than wherever they originated but they will also be harder to observe because they are moving fast. It's not clear we can learn much about the place they originated that we couldn't learn by looking at that place with our telescopes. About all we would learn by observing such stars is that they do indeed exist as theorized.
9. Re:Title by Yebyen · 2014-12-01 08:25 · Score: 1
  
  And I have made a basic error of assuming that 1.0 = 100% (gamma where relativity has no effect) means 1.06-1.0 = 6% (effect of reduction is 6%.)
  To understand the mistake, explain what happens when Gamma is 2.0... I'll give you a hint, it doesn't mean that you are now 100% shorter than you were.
  
  --
  Restating the obvious since nineteen aught five.
10. Re:Title by Anonymous Coward · 2014-12-01 08:46 · Score: 0
  
  In terms of speed, 33% is a pretty significant change from speeds humans usually experience.
  But the dilation would still be small even on human time scales. There is a bigger difference seen in bad adaptations between 50 and 60 Hz TV standards, and even that can go by unnoticed in some contexts.
11. Re:Title by ZombieBraintrust · 2014-12-01 09:08 · Score: 1
  
  Your experiencing 33% right now. We all are. We are moving at 33% the speed of light away or towards these stars.
12. Re:Title by Immerman · 2014-12-01 09:57 · Score: 1
  
  Actually, it's *far* worse than that. Until you hit about 80% of lightspeed you're hardly seeing any relativistic effects at all, and you've got to be well into the nineties before relativity starts getting dramatic. The difference in kinetic energy between a dead standstill and 80% of lightspeed is completely negligible compared to the difference between 95% and 96%.
  It's like saying the 33% on your exam very close to 100%, if you would have gotten a 90% just for spelling your name correctly.
  Then again we're talking astronomy, not particle physics. 0.3c is a radically closer to light speed than most astronomical bodies move relative to their host galaxy.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
13. Re:Title by david_thornley · 2014-12-02 05:34 · Score: 1
  
  When you have to start non-Newtonian physics depends on what you're doing. The dilation factor for these speeds is in the neighborhood of 5%. That's over an hour per day, which is very significant if you're trying to synchronize clocks. On the other hand, it turns a 10 million year trip between galaxies to a 9.5 million year trip. Not that five hundred thousand years is completely negligible, but it's not likely to be enough to make some long trip practical if it wasn't before.
  
  --
  "When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
Iain Banks got there first by Anonymous Coward · 2014-12-01 07:20 · Score: 2, Interesting

Great book set in a planetary system orbitting one of these stars: Against a Dark Background
http://en.wikipedia.org/wiki/Against_a_Dark_Background
Life? by fisted · 2014-12-01 07:20 · Score: 1

Stars traveling at that speed sound pretty deadly to me.

--
CLI paste? paste.pr0.tips!
1. Re:Life? by Anonymous Coward · 2014-12-01 07:28 · Score: 0
  
  Seems relative to me...
2. Re:Life? by Suffering+Bastard · 2014-12-01 08:21 · Score: 1
  
  Stars traveling at that speed sound pretty deadly to me.
  
  Silly human, there's no sound in space.
  
  --
  "Molest me not with this pocket calculator stuff."
  - Deep Thought
3. Re:Life? by rrohbeck · 2014-12-01 09:39 · Score: 1
  
  Yeah, I'd like to see some matter from that star or system interact with something else at "normal" galactic speeds. That would be awesome, space opera stuff a la Doc Smith. A meteor or asteroid at 1/3rd c? Randall Munroe should look into this.
  
  --
  thegodmovie.com - watch it
4. Re:Life? by Immerman · 2014-12-01 09:59 · Score: 2
  
  Well in all fairness, if you get hit by a star you probably aren't going to care how fast it was going...
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
5. Re:Life? by Anonymous Coward · 2014-12-01 11:08 · Score: 0
  
  How about if you don't get hit by the star, but do get hit by a coronal ejection?
  We can get interference by ones from our own sun. One passing by our solar system, too far out to mess up our orbit could still probably do a number on us when the coronal ejection is moving at a third of c hits.
6. Re:Life? by Immerman · 2014-12-01 11:19 · Score: 1
  
  At a distance of multiple light years? Can we even detect the CMEs from Alpha Centauri? Sure, an extra 33%c would boost the energies significantly, but at that distance the ejection would be so diffuse that I suspect it would be completely lost in the continuous background hail of charged particles already hitting us at only tiny fractions of a percent under lightspeed.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
7. Re:Life? by Ferrofluid · 2014-12-01 12:33 · Score: 1
  
  Why?
Space Pinball by Anonymous Coward · 2014-12-01 07:25 · Score: 0

n/t
1. Re:Space Pinball by jfdavis668 · 2014-12-01 09:04 · Score: 1
  
  Ford Prefect: I read of one planet in the seventh dimension got used as a ball in a game of intergalactic bar billiards. Got potted straight into a black hole, killed ten billion people. Arthur Dent: Madness. Total madness. Ford Prefect: Yeah. Only scored thirty points too.
Sexism tags by MildlyTangy · 2014-12-01 07:25 · Score: 2, Insightful

Why the "notsexist" and "!sexist" tags for this article?
I read the summary a couple of times ( yes, I really did! I dont care if you dont believe me ), and I am struggling to find any sexism or innuendo.
Whats the deal?
Is it because of the word "these", or the word "entirely" ?
Or is it because of the sentence "That's more than a third of the speed of light." ?
Its getting really hard to tell these days whats sexist and what isnt, so if somebody could shed some light on this, it would be greatly appreciated.
1. Re:Sexism tags by wonkey_monkey · 2014-12-01 07:44 · Score: 1
  
  Why the "notsexist" and "!sexist" tags for this article?
  I read the summary a couple of times ( yes, I really did! I dont care if you dont believe me ), and I am struggling to find any sexism or innuendo.
  Whats the deal?
  Whadyamean, what's the deal? There's no sexism or innuendo, so it's not sexist. See?
  Like how you're supposed to announce yourself as "not a paedophile" when going to the pool. Right?
  
  Its getting really hard to tell these days whats sexist and what isnt
  That's why we have the tags. This story is simply not sexist.
  I think it should also be on record that it's not racist, just in case, but I guess we're expected to figure that out for ourselves.
  
  --
  systemd is Roko's Basilisk.
How is "more than a third" by macxcool · 2014-12-01 07:40 · Score: 1

'close' to the speed of light? I suppose, compared to how quickly I can move, it's close.
1. Re:How is "more than a third" by Anonymous Coward · 2014-12-01 07:49 · Score: 0
  
  After about 10% of the speed of light quantum mechanical effects become a significant departure from Newtonian physics.
  Of course speed is relative between reference frames, so it's not going 1/3rd of the speed of light to everywhere in the universe. But things get crazy at significant fractions of the speed of light, things like time and space differ between reference frames significantly.
  You get fun effects like apparent length contraction and red-shift which would be noticeable at these speeds.
2. Re:How is "more than a third" by Anonymous Coward · 2014-12-01 08:07 · Score: 0
  
  Even of v = 1/3c the Lorentz Factor is still ~1 and there are minor relativistic effects. Crank the speed up to 0.89c and time on a runaway star elapses at 1/2 the rate relative to its galactic surroundings.
3. Re:How is "more than a third" by Anonymous Coward · 2014-12-01 08:20 · Score: 0
  
  At 0.3c the Lorentz Factor is 1.048, 5% difference in mass and speed is pretty significant on the size of stars.
4. Re:How is "more than a third" by Anonymous Coward · 2014-12-01 08:55 · Score: 0
  
  After about 10% of the speed of light quantum mechanical effects become a significant departure from Newtonian physics.
  You're getting into borderline word salad territory, as that has nothing to do with quantum mechanics and is just plan special relativity effects. Even then, at 10% of c, time and length effects are only about 0.5%. That is quite observable in various contexts with instrumentation, but not exactly significant on a human scale.
Try to imagine that... by angelbar · 2014-12-01 07:51 · Score: 1

(brain) ptrrrr

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-no sig today-
Relativity by Anonymous Coward · 2014-12-01 07:56 · Score: 0

From the reference frame of the star and surrounding solar system, wouldn't it look like the entire universe is rushing somewhere? Can you imagine being in that solar system? You would be saying, "where the hell is the rest of the universe going, and why aren't I going there too!?!?"
1. Re:Relativity by tendrousbeastie · 2014-12-01 09:02 · Score: 1
  
  The star would see the rest of the galaxy as moving slower than it should, to just the same degree that the galaxy would see the star moving slow than it otherwise should.
  Each party would see the other as moving with a slower measure of time than itself.
2. Re:Relativity by dbraden · 2014-12-01 09:03 · Score: 1
  
  Well, yeah, but you would also have the rest of the universe rushing at you, and you would be saying "ah, so that's where we're going!"
3. Re:Relativity by Anonymous Coward · 2014-12-01 10:33 · Score: 0
  
  Epic fail. He was referring to the direction of movement, you cunt.
Stars approaching at the speed of light... by Overzeetop · 2014-12-01 07:59 · Score: 2

Bet you never saw that coming.

--
Is it just my observation, or are there way too many stupid people in the world?
pathetic humans by swell · 2014-12-01 08:04 · Score: 1, Funny

" ... they could also be responsible for spreading life throughout the cosmos."
You humans are so self-centered. You think that because you are 'alive' according to your way of thinking, that being alive is ideal. Anything that 'spreads life' is a good thing.
Well, guess what? Some of us who are not so limited in our thinking happen to believe that your idea of life is erroneous. You fail to consider that you are only the poor expression of a nearly perfect DNA molecule. Your purpose is to continue to propagate until we reach absolute perfection, at which time we till kiss your ass goodbye and continue our travels through the universe.

--
...omphaloskepsis often...
1. Re:pathetic humans by aristotle-dude · 2014-12-01 08:36 · Score: 0
  
  You humans are so self-centered. You think that because you are 'alive' according to your way of thinking, that being alive is ideal. Anything that 'spreads life' is a good thing.
  Put down that peyote and realize that you are a human so where do you get off saying "you humans". Go read Ecclesiastes and know that every human accomplishment is meaningless in the grand scheme of things and every pleasure you seek is also meaningless. Seek god if you want to be happy. Solomon is the man who wrote Ecclesiastes and he tried to find fulfilment in every sensual pleasure, every field of learning and owning every possible possession available to him. None of that gave him true happiness. Only those who know and fear the lord will attain true happiness and fulfilment in their life.
  
  --
  Jesus was a compassionate social conservative who called individuals to sin no more.
2. Re:pathetic humans by Anonymous Coward · 2014-12-01 09:13 · Score: 0
  
  Put down that peyote and realize that you are a human so where do you get off saying "you humans". Go read Ecclesiastes and know that every human accomplishment is meaningless in the grand scheme of things and every pleasure you seek is also meaningless. Seek god if you want to be happy. Solomon is the man who wrote Ecclesiastes and he tried to find fulfilment in every sensual pleasure, every field of learning and owning every possible possession available to him. None of that gave him true happiness. Only those who know and fear the lord will attain true happiness and fulfilment in their life.
  Only the fearful and diffident shall be happy and fulfilled? Oh tell us more doubleplus good speak.
3. Re:pathetic humans by Mogster · 2014-12-01 09:53 · Score: 1
  
  Woooosh...
  
  --
  ACK NAK RST
4. Re:pathetic humans by ColdWetDog · 2014-12-01 10:11 · Score: 1
  
  If that's what it takes to make me 'happy', thanks - but I'll stick with the peyote.
  
  --
  Faster! Faster! Faster would be better!
5. Re:pathetic humans by aristotle-dude · 2014-12-01 16:56 · Score: 0
  
  Put down that peyote and realize that you are a human so where do you get off saying "you humans". Go read Ecclesiastes and know that every human accomplishment is meaningless in the grand scheme of things and every pleasure you seek is also meaningless. Seek god if you want to be happy. Solomon is the man who wrote Ecclesiastes and he tried to find fulfilment in every sensual pleasure, every field of learning and owning every possible possession available to him. None of that gave him true happiness. Only those who know and fear the lord will attain true happiness and fulfilment in their life.
  Only the fearful and diffident shall be happy and fulfilled? Oh tell us more doubleplus good speak.
  *WOOOOOOOOOOOOSH*
  The point you missed is that the acquisition of "things" or seeking to experience all manners of "sensual" pleasure do not result in longterm fulfilment or happiness. Solomon had more gold that any of us will ever have. He could buy what he wanted any time that he wanted. Fear is this case would be awe,reverence or respect for the power of god. That is much different than living in paralyzing "fear". Some fear can be healthy as it helps you stay out of trouble. When you look at something like the Niagara falls in person, does it give you terror or does it cause a sense of awe? Does that feeling give you a positive sense of euphoria? Now imagine a god who created all of that awe inspiring power, other inspiring phenomenon and the universe itself. Now consider such a being caring about you personally. Wild, if you actually think about it even as a thought experiment.
  I can somewhat relate to Solomon. I used to be into acquiring things and travelling around the world experiencing new things but I found that none of that ever really gave me lasting joy.
  
  --
  Jesus was a compassionate social conservative who called individuals to sin no more.
can we by Anonymous Coward · 2014-12-01 08:07 · Score: 0

land a drone on one?
Are there really so many of these? by reve_etrange · 2014-12-01 08:30 · Score: 1

The article says these stars should have a density of about 100,000 per cubic gigaparsec (around 3 * 10^10 cubic light-years). The volume of our galaxy is around 3 * 10^13 cubic light years, which would imply something like 100 million of these stars in our relative vicinity - equivalent to about 0.1% of all the stars in the Milky Way. That seems like a huge proportion to me. Am I missing something?

--
.: Semper Absurda :.
1. Re:Are there really so many of these? by sconeu · 2014-12-01 09:00 · Score: 1
  
  A cubic gigaparsec is a cube with an edge of 3.26 * 10^9 light years. Or roughly a volume of 3.46 * 10^28 cubic light years.
  By your own admission, the galaxy is 15 orders of magnitude smaller than a gigaparsec (disclaimer, I haven't checked your number).
  If there are 10^5 hypervelocity stars in a cubic gigaparsec, then there is roughly a 10^-10 chance of one of them being inside the Milky Way. That's .00000001% probability.
  
  --
  General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
2. Re:Are there really so many of these? by reve_etrange · 2014-12-01 09:58 · Score: 1
  
  OK, I see my mistake - I was thinking a giga (cubic parsec), not a cubic gigaparsec like the article clearly states. Thanks.
  
  --
  .: Semper Absurda :.
3. Re:Are there really so many of these? by sconeu · 2014-12-01 11:33 · Score: 1
  
  No problem. As another calibration tool, consider that the radius of the *CURRENTLY VISIBLE* universe is roughly 5 gigaparsecs.
  
  --
  General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
Energy Requirements by Baby+Duck · 2014-12-01 08:52 · Score: 1

How does something with as much mass as a star gain enough energy to exceed 0.3c within the age of the universe?

--
"Love heals scars love left." -- Henry Rollins
1. Re:Energy Requirements by Anonymous Coward · 2014-12-01 09:13 · Score: 1
  
  How does something with as much mass as a star gain enough energy to exceed 0.3c within the age of the universe?
  RTFA. Stars near supermassive black holes can be accelerated to relativistic velocities if their orbits are sufficiently eccentric. Problem is, they're stuck in those orbits until disrupted or eaten because stars aren't rockets. So, no joy there.
  But binary star systems have built-in rockets, if you will - one star gets eaten or disrupted, the other one keeps all the angular momentum and gets slingshotted out of the galaxy at velocities in ecxess of 0.1c. Wheeeeeeeeee...
  (Yes, it's possible for a star to get close enough to a black hole to experience such acceleration and not get so close that its planets are stripped from their orbits. The star can get within a few light-days of the black hole and planets within a few light-hours, depending on whether they're on the leading/trailing, or near/far side of the star relative to black hole, can remain bound to the star.)
Pretty inaccurate by slashmydots · 2014-12-01 08:53 · Score: 0

By "close" to the speed of light, they mean not even close to the speed of light. To accelerate a standard US space shuttle to 99.99999% light speed would take nearly all the energy in the entire universe. A star is a bit bigger.
I suck a physics but photons emitted in the same direction as the star would slow it down and ones on the back would propel it but since it's already moving and the speed of light doesn't change, there would be a net slowdown from the photons on the "front" end and the star would gradually slow down, right?
1. Re:Pretty inaccurate by Immerman · 2014-12-01 10:12 · Score: 1
  
  Wrong. If that were the case then all the stars in the universe would gradually slow down to "absolute zero speed" (a nonsensical term according to Special Relativity) and condense into a single supermassive black hole.
  What actually happens is that the star expells the photons away with the same force in every direction, resulting in no net acceleration, and it's simply the rest of the universe that sees them as bluer (higher energy, as observed from an approaching reference frame) or redder (lower energy, as observed from a receding reference frame) based on the star's relative velocity.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
2. Re:Pretty inaccurate by Anonymous Coward · 2014-12-01 15:06 · Score: 0
  
  To accelerate a standard US space shuttle to 99.99999% light speed would take nearly all the energy in the entire universe.... I suck a physics
  
  To accelerate ~2000 tons to that speed would require ~4e26 J, which coincidentally is pretty close to what the Sun emits each second. It is nowhere near close to the energy in the visible universe. That is still many orders of magnitude shorter than the energy released in a supernova, which could propel a large moon to that speed. And when something falls into a blackhole, it is possible to extract a significant fraction of the energy equivalent of the object's mass, which for a star would be orders of magnitude larger than the typical supernova.
3. Re:Pretty inaccurate by slashmydots · 2014-12-02 02:43 · Score: 1
  
  Photons emitted in the direction the star is moving cannot be moving at the speed of light plus the speed of the star. They then take off with less energy. Explain that.
4. Re:Pretty inaccurate by Immerman · 2014-12-02 03:43 · Score: 1
  
  You are right. And I actually just explained it, though perhaps not well.
  What happens is that if you fire a photon "forward" it still travels it light speed, but it's waveform gets compressed, converting the kinetic energy of the star into kinetic energy of the photon: that compressed waveform translates to a higher frequency, and thus higher energy, and makes the light appear bluer* (aka blueshift). The speed is the same, but the mass (energy) is greater.
  The exact opposite thing happens to a photon fired "backwards" - it's waveform gets stretched out, reducing its frequency and the energy it carries, and makes the light appear redder (aka redshift).
  I know it seems like the higher-mass blue photons should generate a stronger reaction force, but it doesn't actually work that way. Perhaps someone else can explain the details more clearly, my grasp of the finer points of special relativity is not what it could be. But basically from the reference point of the star all the photons are carrying the same energy in both directions, which ties in to:
  I put "forward" and "backward" in quotes because those are actually completely arbitrary distinctions. Special relativity states that all inertial reference frames are equally valid, so you could just as accurately say that the star is standing perfectly still, while the galaxy is zooming past. The math all works out the same. For example taking our own star as the stationary reference frame: anyone moving toward us, from any direction, will see our sun's light shifted to be bluer. And anyone moving away from us will see the light as redder. And that will be true even as two such travelers pass each other in opposite directions. Despite being in the same location for a moment, one will see our star red-shifted, while the other will see it blue-shifted.
  We routinely use that phenomena to accurately determine a distant star's radial velocity relative to us: Hydrogen always glows brightly at a very precise frequency, so if we look at a distant star through a spectrometer and the "hydrogen line" is redder than it should be we know the star is moving away from us, and can calculate exactly how quickly by just how much the frequency has been shifted. Similarly if it's bluer than it should be we know the star is moving toward us.
  Final note: technically "red" and "blue" are only the conventional names. Basically they're being used as directions on a color spectrum, not as literal colors (though mostly it works out the same) - blue being near the high-energy end of the visible spectrum, and red at the low-energy end. If a star already appeared blue, blue-shift would actually make it appear violet, while a red-shifted green star would appear more yellow. And if the relative velocity is high enough the light will actually be shifted out of the visible spectrum entirely.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
5. Re:Pretty inaccurate by Anonymous Coward · 2014-12-02 05:30 · Score: 0
  
  You could actually just work out the basic math, as is frequently done an intro physics course covering things like special relativity. Simplify it to an object emitting two photons, one forward and one backward. It is easy to work out in its own frame. Then do it again in a moving frame, and you'll still get the same conservation of energy and momentum. The difference in momentum and energy carried by the blue versus red shifted photon will only amount to the amount of momentum lost by the emitter because it shed the mass-energy in the form of two photons. The emitter's momentum decreases, but in proportion to its lost mass and hence goes at the same velocity in the moving frame.
Or maybe... by RatBastard · 2014-12-01 09:02 · Score: 1

Or maybe life is just an inevitable outcome when the right conditions are met? Why science has such a hardon for panspermia is beyond me.

--
Boobies never hurt anyone. - Sherry Glaser.
1. Re:Or maybe... by ColdWetDog · 2014-12-01 10:15 · Score: 2
  
  Because a lot of folks are hoping that there is somebody/thing out there that's smarter than we are. These supreme beings / aliens / Progenitors or someone very much like them will one day wander by and get us out of the intractable mess we've seemed to create for ourselves.
  The logical problem with this is just that if we came from 'them', 'they' might be just as screwed up as we are.
  And that's not a very comforting thought.
  
  --
  Faster! Faster! Faster would be better!
2. Re:Or maybe... by Immerman · 2014-12-01 10:33 · Score: 3, Informative
  
  Simple - because the more we learn about just how durable some life* is, the more it seems inevitable that panspermia happens. Almost certainly between planets within the same solar system, and quite possibly between solar systems as well. Whether it finds fertile ground or not is another question. Basically, even if you assume life "just happens" on a regular basis, panspermia allows it to then spread to places far less hospitable to biogenesis. For example, we have plenty of microbes on Earth that would probably have no problem thriving on Mars, Europa, etc, even if those worlds never offer the rich organic chemical soup and high energy gradients that are probably necessary to spawn life in the first place. When we finally start doing biological studies on those planets it will be very interesting to see if life (A) exists there currently, and (B) is related to Earth life.
  * not to mention pseudo-living molecules like RNA and DNA, which don't necessarily need their host organism in order to reproduce and kick-start the evolutionary cycle on a new world.
  The answers to those questions may tell us a great deal about the probably ubiquity of life in the universe, and is one of the reasons we try so hard to avoid contaminating them with Earthborn life from our probes. If they spawned their own life it may be less sophisticated than what has evolved here, on our lushly energy-rich plaent, and might be completely eradicate by invasive Earth organisms before we ever have a chance to detect it, depriving us of the knowledge that life likely arises pretty much everywhere. Or alternately, if they were colonized by Earth life long ago (Or perhaps we were all colonized by Mars life - it could potentially have supported life long before the Earth cooled sufficiently), then there is much to be learned about the ways that life evolved in (almost) completely isolated ecosystems. Even if there's only microbial life to be found, the evolutionary divergence could make the Galapagos islands look like just more of the same.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
3. Re:Or maybe... by Seraphim_72 · 2014-12-01 18:20 · Score: 1
  
  I only wish I had mod points for you. Panspermia always has rated a "So what?" in my book.
  
  --
  Slashdot, where armchair scientists get shouted down and armchair theologians get modded up.
shooting stars by Anonymous Coward · 2014-12-01 09:21 · Score: 0

Finally some solid proof that they do exist!
1. Re:shooting stars by Immerman · 2014-12-01 10:34 · Score: 1
  
  Nah man. They're out cruising, but their guns couldn't take the heat, reducing them to just yelling and making rude gestures.
  
  --
  --- Most topics have many sides worth arguing, allow me to take one opposite you.
Starship... Star-ship by felixrising · 2014-12-01 09:47 · Score: 2

Putting a new twist on Starships... Literally an Interstellar Star-ship. If you measure civilisations on the Kardashev scale; then a Type 1 -> 2 civilisation should be capable of redirecting a candidate star to place it on a course to travel wherever they want... it might take a long time, but hey, if you want to go traveling across the universe, you'd better do it on a grand scale.
1. Re:Starship... Star-ship by Gavagai80 · 2014-12-01 13:35 · Score: 1
  
  The problem is, in order to orbit the hyper-velocity star or land on one of its planets you need to first achieve hyper-velocity yourself. If you can do that, do you really need the star?
  
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2. Re:Starship... Star-ship by Anonymous Coward · 2014-12-01 14:15 · Score: 0
  
  I was thinking more that they'd place their own star, including it's companion planets on a new trajectory to bring their own star up to hyper-velocities... by slingshotting around several other stars to achieve the desired speeds and direction.
WRONG! by Anonymous Coward · 2014-12-01 09:48 · Score: 0

Speed is relative to the observer, or relative to another body. We could be moving that fast relative to some other body in space. Surprised no one picked that up. http://en.wikipedia.org/wiki/R...
1. Re:WRONG! by Immerman · 2014-12-01 10:37 · Score: 1
  
  Yes, and the "other body" in question here is likely the center of mass of other galaxies in the local cluster. Among which there's definitely some variation in speed, but I don't believe anything on a relativistic scale.
  
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Leeloo Dallas Multipass by aoism · 2014-12-01 10:06 · Score: 2

They could be responsible for spreading life throughout the cosmos, or DESTROYING life. Surely you've all seen The Fifth Element -- and the darkness wasn't moving at nearly the speed of light!
Surviving Speed [Re:Life?] by Tablizer · 2014-12-01 10:28 · Score: 1

Stars traveling at that speed sound pretty deadly to me.
If there are gas giants around such a star, they may pick up some microbes along the way and these microbes may have sufficient protection in the lower atmosphere.
But I imagine an Earth-like planet would be heavily abused by fast encounters with nebula's, dust, and debris encountered along the way.
If they pick up life along the way, I'd bet on it hanging out in gas giants, not rocky planets. (Although such life may periodically drift from a gas giant to rocky siblings to repopulate them during the "good years" via comets etc.)

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arxiv... by bsdasym · 2014-12-01 10:29 · Score: 1

Wonder if submitter (or upvoters) understand that anyone can submit articles to arxiv and have them "published" there, regardless of merit or credentials, and with no peer review. There are articles there on perpetual motion, time travel, and all kinds of other garbage. Arxiv is basically the pastebin of scientific (or pseudoscientific) papers. Anything you read there that hasn't been published elsewhere should be taken with a super massive salt grain.

Pop quiz, hotshot. What is the result of some life form or precursor of life entering an atmosphere or impacting a body of some kind (as required to "spread life") when the object in question has a relativistic velocity compared to the other?

Extra credit, hotshot. Examine the impact of relativistic time dilation on evolution in the system in question.
1. Re:arxiv... by Anonymous Coward · 2014-12-01 15:17 · Score: 0
  
  Wonder if submitter (or upvoters) understand that anyone can submit articles to arxiv and have them "published" there, regardless of merit or credentials, and with no peer review. There are articles there on perpetual motion, time travel, and all kinds of other garbage. Arxiv is basically the pastebin of scientific (or pseudoscientific) papers. Anything you read there that hasn't been published elsewhere should be taken with a super massive salt grain.
  While true in general, not really relevant since this article is being published by PRL.
Lightspeed relative to what? by ssufficool · 2014-12-01 11:15 · Score: 2

I see they finally found that absolute point in the universe that does not move.
A plausible method of intergalactic travel? by smaddox · 2014-12-01 14:36 · Score: 1

If you could accelerate an interstellar ship enough the intercept one of these exiting stars, you could orbit it and use it's radiation to sustain the colony. Eventually, the colony could reach another galaxy.
Of course, this assumes building and accelerating an interstellar ship to c/3 is feasible, which is still a bit of a stretch, though not impossible.
Iain Banks got there first by Anonymous Coward · 2014-12-02 02:20 · Score: 0

I would say Olaf Stapledon was first:
https://en.wikipedia.org/wiki/Star_Maker
The Universe is a constant. Life is everywhere! by iq145 · 2014-12-03 15:19 · Score: 1

There is a 100% chance that life exists on other planets besides Earth. Period. http://www.newser.com/story/17... http://www.newser.com/story/19...
1. Re:The Universe is a constant. Life is everywhere! by Anonymous Coward · 2014-12-03 18:02 · Score: 0
  
  There isn't even 100% chance of life existing on this planet...