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Scientist Claims There's Even More Evidence of Planet Nine's Existence (theverge.com)
An anonymous reader cites an article on The Verge: More evidence is pointing toward a mysterious Neptune-sized planet lurking at the outer edges of our Solar System. One of the scientists who claimed in January to have found strong evidence for a ninth planet -- temporarily named 'Planet Nine' -- now says there are even more clues that support the world's existence. Mike Brown, a planetary astronomer at Caltech University, originally concluded that Planet Nine most likely exists after studying the behaviors of six objects in the Kuiper Belt -- the large cloud of icy bodies that orbit the Sun beyond Neptune. Now Brown is claiming that another Kuiper Belt object supports his theory. The object shares some of the same behavior as the other six Kuiper Belt bodies, suggesting it has also been pushed by a large planet that is between 200 and 1,200 times the distance from the Sun to Earth.
There will always be nine planets. If you get rid of one of the planets, it is inevitable another will come along to fill the void.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
No matter how many more such bodies are found, the story won't be complete until and unless Planet Nine is actually observed and its orbital parameters calculated (I assume that precovery images will be located after the first observations).
. . . . it's Planet Ten, and the Red Lectroids that worry me. . . And no sign of Buckaroo Banzai OR the Hong Kong Cavaliers. . . .
plan 9 from outer space!
... the last time they searched for the 9th planet the economy tanked!
Ain't no such thing.
it could be called Planet X.
Sheesh, evil *and* a jerk. -- Jade
What's that got to do with this?
systemd is Roko's Basilisk.
I vote for Planety McPlanet.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
"Far out!" -- John Denver
I've abandoned my search for truth; now I'm just looking for some useful delusions.
It's more evidence for a weird phenomenon where a bunch of bodies behave in a very non-random, coincidental way. But we already knew about that admittedly interesting thing. In another words: It's like postulating that red lights cause traffic accidents and then, later, pointing that additional evidence for that hypothesis is that more red lights were observed around town.
MikeBrown'sNotPlanet
Gamingmuseum.com: Give your 3D accelerator a rest.
Lord John Whorfin: Where are we going?
The Red Lectroids: Planet Ten!
Lord John Whorfin: When?
The Red Lectroids: Real soon!
I'd like to go there real soon.
putting the 'B' in LGBTQ+
A far out planet could be useful for gravitational assists to the outer solar system.
Pedantically speaking... An actual gravity assist from the planet itself would be worth little - certainly not enough to justify the 1,000+ year diversion (not exaggerating) required to actually take advantage of it.
Getting a gravity assist is analogous to bouncing off of the assisting body. If the body is moving quickly and in an appropriate direction, the spacecraft can pick up a lot of speed (relative to the rest of the solar system) in the process. These conditions would certainly not apply to the hypothetical planet discussed above though:
1) A planet orbiting at that altitude would have an orbital velocity no more than ~7% that of Earth - maybe much less. A gravity assist cannot boost the velocity of the spacecraft by more than the velocity of the assisting body.
2) Achieving a worthwhile gravity assist requires waiting for the orbital phase of the assisting planet and the actual destination to line up right. This could be a loooonnnnggggg wait given that the planet in question would have an orbital period between about 3,000 and 40,000 years...
Having said that, if the planet just so happened to be in roughly the right place already, it might still be worth swinging by it for two reasons:
A) If it had a large moon in a relatively low orbit that was roughly aligned with the plane of the ecliptic, that moon might provide the gravity assist which the planet itself could not.
B) The point of closest approach to the planet may be a good place for an engine burn, to take advantage of the Oberth Effect (which is distinct from a true gravity assist).
Of course - all this "orbital ballet" gravity assist stuff is only necessary because our current propulsion technology is inadequate; any realistic plan for humans to explore the outer solar system would require an upgrade.
Pluto.
So.. the orbits of several comets were disturbed by something large moving through our solar system at some point in the past. While I grant that a large planet is the most mundane explanation.. this could also be caused by either a rogue planet falling into our sun, or.. dare I say.. a very large alien craft moving though our system at some point in the past.
Thou shalt not make a machine in the likeness of a human mind.
I have been laughing my ass off at the thought of these morons whop are such big fans of that TOTAKL CRACKPOT and bullshitter ,Zacharia Sitchin.
And that other bullshitting crackpot Erik Von Danniken and his wee fanyboy asshole, Giorgio A. Tsoukalos - the idiot you see on Ancient Aliens (and I mean that he was/is the chief of Dannikens fan club and is now somehow an expert???).. BUT the hilarious thing is this.....
Michael Heiser , an actual Mesopotamian language scholar says to debunk Sitchin and co
and the whole thesis debunked by Chris White https://www.youtube.com/watch?... and http://ancientaliensdebunked.c... and http://www.sitchiniswrong.com/
Using this you can have a shed load of fun with these morons!
Observe a phenomenon. Think about a possible explanation for the phenomenon. Congratulations, you've postulated a hypothesis.
Gather data which will support your hypothesis. If the evidence does not support your hypothesis, reformulate and try again. If the evidence does support your hypothesis, you now have a theory.
Make a prediction based on your theory. Ensure that your theory is the only possible explanation for the prediction. Run an experiment and test your theory. You're on your way to elucidating a scientific fact.
That's true, Texans always blame the Clinton WH.
This is what happens when you write naming conventions in order to "get" a planet for political reasons!
because it isn't a sphere. I mean it is an ellipsoid or something but it's not close to a circle in shape.
Did you know 80 to 90% of the moderators on slashdot wouldn't recognize a troll even if one dragged them under a bridge.
If no one has directly observed this planet how can we know it's lurking? Perhaps it's sauntering. Maybe walking assertively? Skipping? Where is the evidence for lurking?
Wir sind geboren, um frei zu sein - Rio Reiser
There's a Pak protector out there with a small sphere of Neutronium, holding a small personal planetoid together with proper gravity. :)
He told Larry Niven everything while wasted in a bar, and modern SF was born. :)
Truth isn't Truth - Guliani
. A gravity assist cannot boost the velocity of the spacecraft by more than the velocity of the assisting body.
That is wrong.
The gravity assist comes from the difference of duration "falling" to the body "from behind" versus escaping the gravity field when "in front" of the body.
While both is related to the speed of both bodies, the addition is "energy" and/or "momentum", and the result is a much higher speed increase then just the speed of the "pulling body".
The rest of your logic is right. Nice "upgrade" link though.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Note: For simplicity, I shall assume a Newtonian two-body system (meaning the only significant force, is the gravitational pull of a single massive planet upon a passing spaceship).
That is wrong.
Indeed it is; I forgot a factor of two: the actual limit is twice the assisting body's speed. That's just the theoretical maximum, though; getting close to this in practice requires:
1) A massive assisting body (many moons are too small to be useful)
2) A very close approach (the need not to collide with the body limits this parameter)
3) Precise timing (as I mentioned in my previous post)
4) Proper alignment of the trajectories of the spaceship, the assisting body, and the destination
The gravity assist comes from the difference of duration "falling" to the body "from behind" versus escaping the gravity field when "in front" of the body.
This is incorrect; Newtonian two-body non-intersecting free fall trajectories are always symmetrical in both time and space across an axis drawn through the periapsis (point of closest approach) and the other body. This is the basis for Kepler's laws, which state that all such trajectories are conic sections with the massive body at the focus.
(You can benefit from escaping faster than you fell in - if you do an engine burn at periapsis to accelerate your escape. But then you're using the Oberth Effect, not just a gravity assist.)
A spaceship receiving a gravity assist follows a hyperbolic trajectory. From the planet's frame of reference, the spaceship doesn't actually acquire any additional energy or momentum from the encounter at all; what happens instead is that the direction of the spacecraft's motion is changed, but its speed upon leaving the planet's sphere of influence is the same as it was upon entry (the speed up while falling is exactly cancelled out by the slow down while escaping).
Nevertheless, from an outside frame of reference - such as that of the Sun - the spaceship may gain substantial speed/energy/momentum from the encounter. How? I'll just let the Wiki explain this part:
"A close terrestrial analogy is provided by a tennis ball bouncing off the front of a moving train. Imagine standing on a train platform, and throwing a ball at 30 km/h toward a train approaching at 50 km/h. The driver of the train sees the ball approaching at 80 km/h and then departing at 80 km/h after the ball bounces elastically off the front of the train. Because of the train's motion, however, that departure is at 130 km/h relative to the train platform; the ball has added twice the train's velocity to its own."
If that's confusing and unintuitive - consider giving Kerbal Space Program a try (or just watching some tutorials on YouTube). That's what made this stuff finally "click" for me...
You caught me. ;-)
(In particular, the bit about a large moon in a low orbit being useful, even if the planet itself is not, is something I don't recall every seeing pointed out in any of the "serious" discussion I've read on this topic - but should be rather obvious to anyone who's experimented much with gravity assists in the Jool system.)
With gravity wave detection happening now it may be possible to find something like this in a few decades with a really long baseline on the gravity detector/s. There's already suggestions to network three at points very widely separated around the world (effectively providing a baseline the size of Earth plus an indication of a direction) and offworld detectors on the moon or far beyond may lead to being able to detect something like a Pluto sized planet from it's gravity.
I think with the launch of the James Webb Space Telescope in 2018, this may be the instrument that could find that supposed large object--based on its infrared signature--orbiting a long distance from the Sun, possibly taking around 10,000 years to orbit our Solar System.
But is it a gas giant planet as now proposed? Is it possible the object may actually be a faint brown dwarf star, one that is much smaller than our gas giant planets but with a diameter a couple times that of Earth itself? If it's a brown dwarf, that might explain the strong gravitational influence on our Solar System.
Yeah, sure! Because these astrophysicists have been always right, right? No, most of their theories are blown. Including the formation of the solar system and all it's objects. So you read: ***concluded*** ***most likely*** ***after studying the behaviors of six objects***. This is pseudoscience crawling it's way to de facto science. And keep the money flowing please... we need a new kitchen, and wife wants to visit Paris. People are so brain limited, they might as well send the money.
No, that's a hypothesis with some supporting evidence.
A scientific Theory is a *well-confirmed* explanation of nature - i.e. has solid supporting evidence and commonly widespread acceptance within the field. It differs from a scientific Law primarily in spelling and historical timing - Law having fallen out of common use as we came to accept that our understanding of the universe is far shakier than we once imagined.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
The gravity assist comes from the difference of duration "falling" to the body "from behind" versus escaping the gravity field when "in front" of the body.
This is incorrect;
No it is not ;D pfffft. As you explained so eloquent and quoted wikipedia:
"A close terrestrial analogy is provided by a tennis ball bouncing off the front of a moving train. Imagine standing on a train platform, and throwing a ball at 30 km/h toward a train approaching at 50 km/h. The driver of the train sees the ball approaching at 80 km/h and then departing at 80 km/h after the ball bounces elastically off the front of the train. Because of the train's motion, however, that departure is at 130 km/h relative to the train platform; the ball has added twice the train's velocity to its own."
From the point of view of the sun, it is exactly as I explained above. You fly quicker out of the "gravity well" then you needed time to enter it.
I agree that your explanation is better, though.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
That was one of the proposed criteria. If you believe that it was one of the accepted grounds, then you either haven't followed the actual science (highly likely), or you've been listening to really poor press reporting (of which there is a lot) and misunderstood the science.
For what it's worth, I argued for the roundness criterion (sometimes described by the orbits and dynamics people as "a materials science argument," which considerably misstates the point). But since I haven't earned my chops as a planetary scientist (just another geologist), I didn't get a vote, and would have lost anyway. Roundness is not a criterion for whether or not something is a planet.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
From the point of view of the sun, it is exactly as I explained above. You fly quicker out of the "gravity well" then you needed time to enter it.
Sorry, but no. Such a thing would be possible under Relativity, but in Newtonian mechanics all observers must agree about the timing of events (provided that they are truly being asked the same question).
In the train example, an observer on the platform and one on the train will both give the same answer to the following questions:
1) How much time passed from the point at which the ball was 10 meters from the front of the train, until it hit the train?
2) How much time passed from the point at which the ball hit the train, until it was again 10 meters from the front of the train?
In the same way, the time for a spacecraft receiving a gravity assist to "enter" and to "fly ... out" are both defined based on the craft's altitude above the assisting body, which is moving from the Sun's perspective. The motion of the body synchronizes with that of the craft in such a way as to make the time-line consistent, regardless of whether you observe it from the Sun's perspective, or the assisting body's.
Sorry, but no.
Your explanation left aside: Sorry, but yes.
1) How much time passed from the point at which the ball was 10 meters from the front of the train, until it hit the train?
x seconds
2) How much time passed from the point at which the ball hit the train, until it was again 10 meters from the front of the train?
x-dV seconds
The ball gains momentum from the train in an elastic collision. The train loses momentum.
Or in other words: in the second question the ball is faster than in the fist question and the train is slower. Hence the time to be 10 meters away is shorter in case 2) than in case 1)
You seem to be very good at physics but I don't get why you don't grasp that an gravity sling shot is just a kind of an elastic collision in space ... albeit with a bit weird "vectors of movement".
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
The ball gains momentum from the train in an elastic collision. The train loses momentum.
Or in other words: in the second question the ball is faster than in the first question and the train is slower.
Let [mA] be the mass of the smaller object.
Let [mB] be the mass of the larger object.
Let [vA0] and [vB0] be the pre-collision velocities of the two objects.
Let [vA1] and [vB1] be the post-collision velocities of the two objects.
Let [AB] = [mA] / [mB], which is the ratio of the lesser mass to the greater.
With a little algebra: [mB] = [mA] / [AB]
By the law of conservation of momentum: [mA]*[vA0] + [mB]*[vB0] = [mA]*[vA1] + [mB]*[vB1]
By substitution: [mA]*[vA0] + ([mA] / [AB])*[vB0] = [mA]*[vA1] + ([mA] / [AB])*[vB1]
By subtraction: [mA]*[vA0] - [mA]*[vA1] = ([mA] / [AB])*[vB1] - ([mA] / [AB])*[vB0]
By division: [vB1] - [vB0] = ([mA]*[vA0] - [mA]*[vA1]) / ([mA] / [AB])
Simplified: [vB1] - [vB0] = [AB]*([vA0] - [vA1])
Let [dvB] = [vB1] - [vB0] and [dvA] = [vA1] - [vA0]
By substitution: [dvB] = -[AB]*[dvA]
By division: [dvB] / [dvA] = -[AB]
From the above, we can see that the ratio of change in velocity for the train versus the ball, or the spacecraft versus the planet, is equal to the (negated) ratio of the smaller mass to the greater mass:
A large train weighs in excess of 10^6 kg. A tennis ball weighs less than 0.06 kg. Thus:
[AB] = [6*10^-2 kg] / [10^6 kg] = [6*10^-8]
[dvA] = [-130 km/h] - [+30 km/h] = [-160 km/h]
[dvB] = -[AB]*[dvA]
[dvB] = -[6*10^-8]*[-160 km/h] = [9.6*10^-6 km/h]
So technically, yes the train slows down - by an immeasurably small amount that is completely irrelevant for any purpose other than ensuring conservation of momentum. #1 takes a mere 0.45 seconds, but #2 also needs an extra 54 nanoseconds.
I would approve your answer here as pedantically correct... except that the application you have attempted to make of it to gravity assists is just dead wrong:
x-dV seconds
That's obviously invalid, and not helpful at all. x and dV are specified in different types of units (time versus speed), so one cannot be directly subtracted from the other like that. Repeating the math from above, but now for the gravity assist case:
A truly gigantic manned spacecraft (required for such a long journey) might weigh 10^7 kilograms, while an ice giant like the theorized "Planet Nine" might weigh 10^26 kg (like Neptune). The maximum plausible velocity change for the spacecraft from the gravity assist would be around 4 km/s.
[AB] = [10^7 kg] / [10^26 kg] = [10^-19]
[dvA] = [4 km/s]
[dvB] = -[AB]*[dvA]
[dvB] = -[10^-19]*[4 km/s] = [-4*10^-19 km/s]
Now that we know roughly how much "Planet Nine" could be slowed down by an encounter with our spaceship, we can calculate how much faster the ship will escape the planet's gravity well as a result. We'll use Neptune's Hill Sphere radius as a reasonable (and lazy) approximation for the size of the well.
[ship speed] = [2 km/s] Note: As in the train case, from the planet's frame of reference, the ship does not (in net) speed up; it only changes direction.
[planet dV] = [-4*10^-19 km/s]
[Hill radius] = [1.16*10^8 km]
[inbound time] = [Hill radius] / [ship speed]
[inbound time] = [1.16*10^8 km] / [2 km/s] = [5.8*10^7 s]
[outbound time] = [radius] / ([ship speed] + [planet dV])
[outbound time] = [1.16*10^8 km] / ([2 km/s] + [-4*10^-19 km/s]) = [5.8*10^7 s] + [1.16*10^-11 s]
The above formula is grossly oversimplified (since, unlike an actual elastic collision, this acceleration is far from instantaneous) - but should nevertheless
[5.8*10^7 s] + [1.16*10^-11 s]
That should obviously be a minus in the middle, not a plus; the escape is faster, not slower.
there is simply NO WAY that taking an extra 1/100th of a nanosecond to escape
Again, this should be "taking one 1/100th of a nanosecond less to escape", not "more".
I should really proof-read this stuff more carefully - but in this case it does not change the ultimate conclusion at all.