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Bright Star Getting Brighter
jwhyche writes "Just what the heck is Eta Carinae doing? Well astronomers are not quite sure. After being one of the brightest stars in the Southern sky it dimmed for a few decades. Now it's back, emiting five time the energy of the sun, and is right next door. So, how big is a hypernova explosion anyways? Big boom anyone? "
Very nice recap.
A couple minor points:
1) there is not really any evidence that supernovae typically result in black holes. While theory does *predict* black holes, they are notoriously hard to detect. In fact most theories predict neutron stars and many have been been found in supernova remnants, including the Crab Pulsar in the remnant of the 1054 AD supernova.
2) LBVs are thought to be of order 70-100 solar masses, as opposed to the 30 or 40 suggested.
That's kind of tough if they don't know where our doorstep is.
You may then think that "if they know how to create a huge burst of gamma radiation, then they must be advanced enough to find us", but I say nay, not neccessarily. They may have the means to spray a little lighter fluid on a nearby sun without killing themselves, (no small feat, I admit), but they may well be no further along than us in terms of actual interstellar travel and communications.
Remember the soldier's curse about lighting more than 2 smokes with a single match? Crouch in a field on a moonless night and no one can see you. Now light a single match...
I admire the work of SETI, but I think our time would be better spent drawing attention to ourselves in conjunction with scanning the heavens at random.
I really don't think 'THEY' have seen us. When they do, we'll hear about it, for better or worse.
**>>BELCH
Perhaps you know of a way to transmit data faster than the speed of light. :)
This is what confuses me about this theory:
1) Obviously they wouldn't do this to their own star, it would be too risky. They'd have to go to another solar system to do this.
2) They couldn't do it to a star that was too close for the same reason. They'd have to go a good distance, just in case they completely screwed up and caused a hypernova. They don't want to wipe out their civilization.
3) Why would they travel the many many light years it would take just to send a message no one is going to receive for centuries and probably won't understand, anyway, when they get it?
I suppose that if they have the capability of manipulating a star, they could conceivably have faster than light travel IF faster than light travel is possible, which wouldn't make the trip so bad.
Of course I'm also assuming that they can't manipulate the star from a great distance also, which isn't neccessarily so.
Pretty much, this whole post is a waste, then.
-
-
It is possible for your mind to be so open that your brain falls out.
Well, if there's a bright center to the universe, you're on the planet it's farthest from.
The schwartschild radius of the black hole would be roughly that of the initial radius of the star. Don't worry about it. The gravitational effects of the black hole on us, would be the same as the star's.
would a black hole that close have effects on us?
The "resetting the clock" theory is that the young Milky Way galaxy was being sterilized by stellar radiation bursts about every 200 million years. Any life was destroyed. We hope the galaxy is old enough now that it won't happen again too soon. Of course, we're not a colony planet already because other life began at around the same time as us, so has not had time to spread throughout the galaxy already.
As long as we can live through whatever it does, now that the astronomers have noticed it they'll be getting a good show. Even becoming a quiet star will be interesting.
Also, the so called "homunculus", the dust cloud that surrounds eta carina, points to what youm were saying
It's a good thing we live out in the unfashionable end of a spiral arm of our galaxy. The core probably has some fearsome radiation levels.
Dangerous to you and I, but to the Zoltans of Gorkus, just to the left of the core, our system has far too little radiation to survive.
Perhaps a hypernova is just something advanced alien beings do when they can't find a decent space heater?
Anthropo-centricity! They were sending news broadcasts to their neear-neghbors the Clongdinthers, we just happened to get the message as well.
# If Eta Carinae becomes a black hole, would it
# be the closest known black hole, or does
# anyone know of one that is closer to us?
It would be the closest known black hole. (Unless Sagittarius A, at the center of the Milky Way, is closer??)
And we'd get a big radiation blast, due to its proximity. Esp. if it goes hypernova! Unfortunately, I don't think we're quite sure what causes hypernovae, so its hard to say whether this is a possibility.
I'd sure like to fit models around my hypo! :)
for the record, i am actually quite happy that you mentioned this, i'll now have to see about getting a look at that.
If I remember correctly, a black hole will add the things it sucks in to its mass, thus increasing it's gravitational pull. It would take a pretty unimaginable amount of mass in order to have an effect on us though. We (humans that is) probably won't be around long enough for that to happen anyway. Something else will likely kill most or all of us off long before we have to worry about black holes. Right now they are just a curiosity and are mainly interesting due to the fact that they are the most efficient producer of energy in the known universe.
I'm not an astronomer (not even an amateur), so I'm sure someone will correct whatever I screwed up :)
It's not enough to bash in heads, you've got to bash in minds. - Captain Hammer
Posted by FascDot Killed My Previous Use:
So you won't be killed in the initial burst. Great! You'll just die a slow painful death in the aftermath.
--
"Please remember that how you say something is often more important than what you say." - Rob Malda
Someone (I forget who) once theorized that the best way for aliens to contact us would be to modulate heavenly phenomenon in such a way that we would take note of it. For one, seeing as how we are constantly observing astonomical phenomenon, this would be a good way for the aliens to improve our chances of actually seeing the message, and two, we'd probably notice any glaring anomalies. So, Could this be the one? The SETI guys should sic their signal processing algorithms on the spectrum coming from this star.
Where's the Immodium P38 Space Modulator when you need it?
Obviously the aliens think we have a case of intergalactic diarrhea if they're launching Immodium at us.
Okay, tag this at "-1" and move on...
Well... Astronomy is a difficult system..
;-)
I'm sure some of you have tred debugging a system via the internet and wished you could get your hands on teh machien to figure it out.
In astronomy we only see things from one angle.
Anyway... we don't get enough money to do all the research we';d like to - if you want answers you need to get the Governments to give us the resources to get them
Obi Wan: That's not a star, it's a space station.
Han: I have a bad feeling about this.
Obi Wan: Dang, that was my line.
Pretty close. Basically, a black hole, from far enough away, affects you just like any other object of the same mass. If the sun turned into a black hole right now, it's get dark and cold and we'd have other problems after a while but our orbit wouldn't be affected and we wouldn't have to worry about getting "sucked in".
Basically, if Eta Carinae did turn into a black hole, we would be trading a visible 100+ solar mass for an invisible 100+ solar mass. (Okay, we'd see the accretion disk, but that's chickenfeed.)
Yogurt: May the Schwarzchild be with you.
Lonestar: KABOOM!
"I just know they're going to probe my anus."
Wow, 99% that's a lot. I'd like to see a story on that here at Slashdot. Rob...?
http://orangeroad.org/fanfic.html - Check the first fanfic there.
On your everday life? Not much, probably...
It will however give the scientists a better view at a Black Hole. They might be able to study it and find new stuff out about it.
But don't worry, it's not going to gobble us up.
The lower limit for a stellar mass black hole is only about 3 solar masses. Eta Carinae is about 100 solar masses. This doesn't mean every star over 3 solar masses will become a black hole. It just means if what is left after the super(or hyper)nova is bigger than 3 solar masses, the remnant will collapse into a black hole.
Nuetrinos don't have any effect on the human body (for the same reason rock won't protect you)they just don't interact with matter much at all.
--
"L'IT c'est moi!"
But like I said, I don't know what I'm talking about.
-----BEGIN ANNOYING SIG BLOCK-----
Evan
rooooar
Cool, we get to witness the explosion of the Death Star 7,500 years after Luke Skywalker blew it up. Movie didn't mention all that pesky invisible radiation, though.
A bit more seriously, 7,500 light years is chump change astronomically. How big of a black hole would this thing form, and how long would it take to suck us down into it? (ok I'm being facetious) Are there any other stars by Eta Carinae they can compare this to? And how does this tie in to the way we usually predict stars die, if that is what this thing is indeed doing?
~afniv
"Man könnte froh sein, wenn die Luft so rein wäre wie das Bier"
~afniv
"Man könnte froh sein, wenn die Luft so rein wäre wie das Bier"
Richard von Weizs
It's always fun watching the news media try to get astronomy right.
:-)=
Actually, I'm fairly impressed that there were only two glaring errors that were obvious without having read the press release or paper. The first was on the caption that shortened Eta Carinae to just "Eta". Ca ne marche pas. Eta Car would have been okay, but might have confused people?
The other one was a biggie, though. They say that hCar is about 100 times the mass of the sun (right) and shines 5 times brighter (wrong). I'm guessing what was actually said was either "10^5 times brighter" or "5 orders of magnitude brighter". Might also have been "5 magnitudes brighter", but that would only be 100x brighter, which wouldn't be right.
Still, if they're only off by a factor of 20,000, that's better than a lot of other astronomy news stories I've seen...
What a really lame web-article this is? I mean really, there were relatively few blatant errors, but what about a proper set of related links? No links to the hubble page, none U Colorado, not even a link under the picture that I can click to get a high-res version. Sure it's an AP wire article, but they could put in some links to pages besides their own and their ad links, don't you think, perhaps just one, for those that might want some more info?
Geez ABC, WAKE UP! This is not the evening news on TV or radio!
Good judgement comes from experience, and experience comes from bad judgement.
- W. Wriston, former Citibank CEO
Oh, yes, I have a Nova Velorum. Doesn't accelerate very fast, but the gas mileage is good. And the seat covers feel so nice when I'm wearing short pants.
It would theoretically be the closest black hole Though scientists have hypothesized that a black hole exists outside our solar system for a while now.
That would be true if this was likely to be your common or garden-variety supernova. If it's a hypernova, that 5625 doesn't seem quite so large a safety-margin.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
And yeah was there a vast a mightly light shining down fron the heavens and lo did the many run in fear, for they felt the day of reckoning was at hand. Or maybe a star exploded 7500 years ago in a galaxy far, far away, who can tell.....
(whisper: first post, and a silly one at that)
+&x
Well, I'm sure going to miss those Australian aborigines, but at least the rest of us will be okay!
Radio waves are great, but there's nothing like a flash in the pan to get some attention.
**>>BELCH
Gravity Waves? What?
I cought this on cnn.com, and one of the things that truly amazed me was that the astronomers were publicly admitting that they didn't know what was happening.
You won't see many people admitting to the press that they don't have a clue. I mean when was the last time that you heard someone at any computer company say "Yep, that's a problem. Don't have any idea what it could possibly be"
Most of the time they'll deny that it exists, or just say, "oh, yes, we've been working on that at some time, expect a press release in the near future"
I'm just glad that _someone_ out there admits when they're wrong or clueless.
Uhmm... Neutrino don't *DO* anything.
That's their characteristic, and thats why the're
so incredibly hard to detect.
It is 5 or maybe just 4 million times brighter depended on where you get your information.
Apparently we are getting more heat from this thing than from any other object in space (outside the solar system.)
send + more == money?
The Sun has brightened by 0.15% during the current sunspot cycle, and the Sun's long term variation might exceed 0.5% [Nature,399(6735),416-417].
A friend of my gave a presentation of the work he did with Don Lamb's group where they showed that the odds of GRBs being associated with type IIa(?) supernovae was something like 30000 to 1, the odds for other types were better (on the order of 10 to 1) but that was only because they didn't have as much data on these other supernovae(type IIc). So I'm not sure that supernovae are associated with GRBs
"When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it
They look like they're covers to Pink Floyd albums, similar to Meddle and Saucerful of Secrets.
To the moderators: Don't mark this as offtopic -- humor is a good thing.
Slashdot's first reaction to VMware
Now I'm no serious physicist, but I do know that 7500 LHY is a stone's throw interstellar-wise. It's important to remember that stellar events involve a shitload of relativistic phenomena that can make them very interesting. I could see a potential simultaneous collapse/hypernova scenario that could cause those polar jets to spew all sorts of elementary particles a distance that could equal the radius of a small galaxy, albeit briefly. Sort of like a flash bulb. Wouldn't want to be caught in that.
Brak: What's THAT?
Thundercleese: A light switch.. of TOTAL DEVASTATION!
7500 light years is a good amount of elbow room. Now if it was say 100 LY away I'd start to worry. A supernova at that distance would probably sterilize the earth. It's a good thing we live out in the unfashionable end of a spiral arm of our galaxy. The core probably has some fearsome radiation levels.
Silly! While the discharge is getting closer, you don't see it. Unless they're powering it up. If it keeps intensifying as thousands of giant space hamsters pedal their giant space hearts into a giant space heart attack, then we're in trouble.
The fact that they mostly pass through you is precisely why the planet can't protect you. The key is *MOSTLY*.
If 99.9999999% of neutrinos pass through you without incident, then 1,000,000,000 neutrinos passing through you will result in one hitting you. And 1,000,000,000,000,000 neutrinos passing through you will result in 1,000,000 hitting you. And 10^20 neutrinos will result in 10^11 hitting you.
The point is, at some level of neutrino radiation, you are going to get baked. And there's some theoretical basis for suspecting that some stellar explosions can result in a *LOT* of neutrinos. It was in some article I read in Science News a few years ago. We need a real astronomer here to give us the lowdown.
I hope we have "gamma-block 1Million" sun-screen lotion by then........
Guyote was here.....
Either the neutrinos pass harmlessly through the planet, and hence all of us; or even the planet can't stop their horrible advance... which means nothing ON the planet will stop them either. Either way, nothing you do will matter. So don't worry about it.
If Eta Carinae becomes a black hole, would it be the closest known black hole, or does anyone know of one that is closer to us?
Should make for an interesting show if it goes nova... I wonder if we'd get any sort of increase in cosmic radiation (which has happened from other supernovas, apparently).
-tbo
Here is a link. And another, and another. Funky!
-- What you do today will cost you a day of your life.
If the neutrinos go through a planet full of rock, what makes you think they won't fly right through you as well?
You've got neutrinos flying through you every instant of your existance... Sol puts 'em out, too. Don't worry about it.
I don't think a blast of neutrinos would have any health side-effects. They typically pass harmlessly through the body.
I like this story. I read in New Scientist recently that some astronomers think that occasional hypernovas wipe out all advanced life in a galaxy every few billion years which explains why none have yet contacted us.
So they're not sure what is going on and the most likely explanation seem to be either its some ET trying to get our attention, or its some big bad hypernova which could conceivably irradicate us and finally answer the question of why you should use spare cycles to crack RC5 instead of SETI.
It seems like sending a radio message would be less work than making a star behave strangely, so my money is on the hypernova.
http://rareformnewmedia.com/
Looks like the Moties turned on the propulsion laser again ... :-)
And shall we elect Nova Palpatine instead????
Maybe those of the Slashdot persuasion only care about potentially dangerous stars.
This isn't a very good article. Eta Carinae is merely the closest example of a class of stars known as Luminous Blue Variables (LBVs) which have been found in other galaxies and in the center of our own galaxy, obscured by dust.
When a massive star (more than thirty or forty times the Sun's mass) forms, the luminosity is so high that radiation pressure causes the star to lose mass. In the largest stars there is instability- the luminosity will sometimes increase to a few times its normal level and be emitted at shorter wavelengths humans can see, leading to a several hundredfold increase in visible radiation. This is accompanied by ejection of the star's surface layers.
Eta Carinae is believed to have been a bit brighter than it is now before around 1800, and then it underwent an outburst for a few decades in the mid-nineteenth century, becoming the second brightest star in the sky for a while. The star then faded to the limits of human vision for a while and has recovered somewhat in the twentieth century.
The luminosity of Eta Carinae has (for the past couple of centuries, at least) been tens of thousands of times that of the Sun. Most of the energy is emitted in the far ultraviolet, and the star is also behind a thick screen of dust that blocks most of the light which is visible (around ten percent is believed to get through).
A conventional supernova explosion at this distance would be a very bright star, comparable roughly to the planet Venus (currently visible in the west just after sunset). Supernovae of comparable intensity were seen in 1006, 1054, and 1572, so this is not an uncommon event. Supernovae of this size typically result in a black hole. Since these are not terribly uncommon, the nearest example of a black hole is probably at a distance of only a few hundred light years. The local interstellar medium has been cleared out by a supernova shock wave recently which is believed to be in the Scorpius-Centaurus Association, a group of easily visible stars around 500 light years away.
There are some theories which suggest that maybe large systems might do something more exotic, such as conversion of several solar masses of material into energy by gravitational collapse. This is an attempt to explain bright flashes seen in gamma-ray bursters (you can see one for a few minutes in binoculars from a distance of billions of light years) without having to have the energy come out preferentially in one direction. This competes with other theories in which the energy output of gamma-ray bursters is beamed.
My guess is that gamma-ray bursters are not connected with LBVs because there should be a much higher rate of LBVs dying than observed gamma-ray bursts.
Remember, these stories don't just magically appear. Slashdot consists mostly of user-submitted stories. If you see something of significance that should be posted here, submit it! That's what the link on the left side of everything titled "submit story" is for, after all!
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
...as the song goes.
The more that pass through a given volume of matter, the greater the chance that some will actually collide with something, creating slower, more massive particles that CAN do damage.
Fortunately for us, the average # of neutrinos
we have received historically from cosmic events
like supernovae have been less than 10 per event.
The 1987A supernova registered a total of 11 detection events @ the Kamiokande detector in Japan IIRC. This was considered high.
Not worried about the neutrinos. Why? They don't really interact with anything much. How else do you think they pass through the earth? Neutrinos are not ionizing radiation in the same sense of gamma rays and cosmic radiation.
Why do they build those big underground caverns filled with this or that fluid to try and detect a very rare collision of a neutrino with something in the fluid, when the flux of neutrinos from the sun is definitely not trivial (if it were gamma rays, we'd be toast)?
Your probably looking for the sci-tech section of of the bbc news page.
BBC Science News
Gamma rays wouldn't make it through the earth though.
Biological Effects of Stellar Collapse Neutrinos article from the astro-ph archive
Unless it zaps us with a heavy dose of neutrinos as well. A planet's worth of rock won't protect us in that case.
It already is an interesting show, although it would become less interesting if it goes nova as it will blind us for a while from seeing the nearby stuff which presently makes it so pretty. At least the southern hemisphere would get to see the bright light in the sky for a while.
We'd get some increase, but it would probably have to go supernova for a significant amount of radiation to get past our atmosphere.
Of course, a supernova would geneate a neutrino burst (most supernova models require it, or else the blast does not happen). I think we already have 300 neutrinos per cubic centimeter, and I don't know at what level they ...um.. become toxic.
Seems kinda lite for making a Black hole.
Well. I wouldn't count on it NOT giving the earth
a good dose or two... The amount of radiation it could emit would be amazingly intense. Previous supernovas were felt on earth, a tiny bit. I think they caught like 23 nutrinos (there were many more but those were the only ones detected) from the last big supernova. What happens when star that is this close (it's not THAT far) blows, and blows big? I'd rather not find out.
But, it problably won't happen in our lifetime.
- Paradox
Slashdot. It's Not For Common Sense
... it happened thousands of years ago. Can't you find some real news? :-)
support gun control: take guns from cops
Hypernova are approximately 100 times more powerful than supernova. This still gives a fudge factor of approximately 55 times. So it's equivalent to a supernova at a distance of about 750 light years. A supernova at this distance would be harmful, but again not a complete killer. It still wouldn't be healthy but nothing like a close up view of a supernova. Now if a hypernova went off within ~1000 light years, we would be completely screwed.
Of course if the hypernova are a factor of 10,000 times as energetic as a supernova we would be cooked. Though since it probably won't happen in the next millenium or so gives us plenty of time to advance and prevent this kind of thing from wiping us out.
I think it's very exciting that they dont know what is going on. Now they have to re-think it all over again and hopefully they'll be moving closer to the truth.
Without discovery there is no science.
-Rich
I call for a vote of no confidence in Nova Velorum!
Sorry dude, you're as good as toast. (I'm kidding) Neutrinos rarely, if ever, interact with matter.
http://www.skypub.com/news/990528.html
It's not a star. It's the energy discharge fired at us by the Aliens. The brightening of the 'star' is the discharge getting closer to us.
Where's the Immodium P38 Space Modulator when you need it?
Nova Velorum appeared about a week ago (but slashdot didn' think that a new star in the sky was worth reporting.....:-( ).
It's the brightest Nova for 20 years - second magnitude - brighter than most of the stars in teh sky.
Eta Carinae is fun...
I think I have a crude understanding of a supernova: star uses up it's fuel and collapses, core is crushed to density of a neutron star and then stops, resulting "bounce" creates shockwave which blows the star to bits, leaving a neutron star or black hole and an expanding nebula.
So what's a hypernova? How's it different from a supernova?
http://a188-l009.rit.edu/rich mond/answers/snrisks.txt
Analyzes the threat from X-rays, gamma rays, neutrinos, and energetic particles (cosmic rays).
Also, check out this newsgroup thread:
sci.astro.amateur: closest safe supernova?
Sorry. I read over in sci.astro, I think, that some activity was spotted around Cygnaus X-1. That ruled it out as a black hole. I wished I had save that piece.
I read at +2. If your post doesn't reach that level I will not see or respond to it.
They typically pass harmlessly through the body.
Kinda like corn right?
If we got sterilised we'd have to clone ourselves to keep the human race going...
>Of course if the hypernova are a factor of 10,000 times as energetic as a supernova we would be cooked. Though since it probably won't happen in the next millenium or so gives us plenty of time to advance and prevent this kind of thing from wiping us out.
PFFT! (Spews drink)
Like what?!? Switching back to lead based paint?
This is interesting though. I never considered that there is probably no intellegent life near the core of our galaxy because exploding stars would wipe out any life nearby.
Later
Erik Z
Democrats or Republicans. They are both taking us to the same place and they are not afraid of us anymore.
It's been an odd and reasonably regular theme in "alien abductee stories" that the aliens give the abudctees prophecies of future global doom, generally to happen in a few decades.
Yes, this is a long-standing cultural meme since the old testament so it could be wholly spurious, but....
what if....
1) The aliens were really real and coming here
2) They would somehow have ''warp drive''
3) The hypernova in Eta Carinae happened
4) After losing all sorts of interstellar saucers without warning when going into some piece of space, they mapped the expanding sphere or solid angle (it needn't be isotropic) of lethal radiation.
5) They know exactly when it's arriving here.
6) We're fucked.
I'm talking about the kind of radiation that would completely sterilize the earth. Nothing would live through it , not even cockroaches, not even Dick Clark. At 75 times the distance, the amount of radiation necessary for us to be wiped out would have to 5625 times as strong a source. The difference between this and a regular supernova won't be that spectacular I imagine.
Oh sure in a worst case scenario, there might be a year or two where it would be a phenomonally bad idea to go out and suntan. There might be some species die off, and a higher mutation rate. But nothing like a close by Supernova. A close by Supernova would do quite a bit more than strip the paint off your house and give your cat a permanent orange afro.
Well, I've always found Eta Carina an interesting oddball. Try to find he high-res shots the Hubble took of it, it looks like something out of a sci-fi movie.
That'll be quite a show if it blows. A heavy gamma-ray burst would kind of be a downer, but hey, I live in the Northern Hemisphere, I've got a planet's worth of rock between me and the star.
Either the supernova is so far away that nothing is going to happen to us, or it's close enough to produce the effects you mention -- which means that if (as was stated waaaaay up in this thread) that if the entire mass of the planet Earth is not enough to shield you from it, there's nothing any of us can do to stop it.
As there is no productive action to be taken in either case, there is no point to worrying about it.
I like this ABC News science site, but I lost the URL of the BBC site, which is even better. Can someone please give me the BBC URL?