When Worlds Collide
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- Опубліковано 2 чер 2010
- / sciencereason ... The Hidden Universe of the Spitzer Space Telescope (Episode 33): When Worlds Collide.
When worlds collide, the result is spectacular, and astronomers think they've detected the aftermath of such an event around another star.
This is the Hidden Universe of the Spitzer Space Telescope, exploring the mysteries of infrared astronomy with your host Dr. Robert Hurt.
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Nearly 60 years ago, audiences thrilled to the destruction of the Earth in George Pal's classic film, "When Worlds Collide." The idea of a planetary smash-up is a staple of science fiction, but can it really happen? Astronomers using NASA's Spitzer Space Telescope think they've actually seen the aftermath of such a collision around another star. It can even help us understand similar calamities that happened long ago in our own solar system.
The story unfolded as Dr. Casey Lisse and his team studied disks around young stars. Once planets have formed astronomers think there are a lot of left-over asteroids in the system. They occasionally slam together and produce dusty debris. Spitzer's Infrared Spectrograph was designed to detect the faint glow from this material. By spreading the light out into its component colors, astronomers can look for the spectral fingerprints of different minerals. This way we can figure out the composition of disks around other stars.
Our dusty star of interest is a faint speck known as HD 172555. It's about 100 light years away and 12 million years old which, compared to our 4.5 billion year old Sun, is like a baby born a few days ago. Studying its spectrum, Dr. Lisse and his colleagues realized they had found something very peculiar that they had not seen around other stars. Aside from the usual indicators of rocky rubble, they found features corresponding to tektite, obsidian, and silicon monoxide gas.
What's strange is that tektite and obsidian are formed from molten materials. Tektites are hardened chunks of lava found around meteor impacts on Earth, and obsidian is volcanic glass. Vaporized rocks can form silicon monoxide gas. You don't get this kind of material by just smashing a couple of asteroids together. The evidence suggests something much more... cataclysmic.
Imagine what would happen if our moon slammed, at high velocity, into a Mercury-sized planet. The resulting impact would eject a massive amount of molten material into space. As it cooled it would likely form tektite, obsidian, and silicon monoxide gas, explaining the features seen in the HD 172555 spectrum.
It's amazing to think Spitzer may have caught the aftermath of such an incredible collision. But, it's not the first time astronomers have speculated about world-shattering events. Things like this may have happened right here in our own back yard.
Mercury is a strangely dense planet compared to the other rocky worlds in our solar system. If it formed from the same stuff as Venus and Earth, why would it be different? A world-shattering impact could be the answer. When planets form the lighter materials rise and denser ones sink to the core. Remove the outer, lighter layer, and you're left with a denser planet, once what's left cools off.
Looking to our neighbor Mars we see a massive impact scar in its Southern hemisphere. This area, known as the Hellas Basin, must have formed from an asteroid impact long ago. The resulting plume of molten material would have been blasted into space, some of it eventually reaching the ancient Earth.
Even closer to home, most astronomers believe that our own moon was the result of a similar cataclysm. The theory is that a Mars-sized body grazed the stillforming Earth, generating a massive amount of molten debris. The orbiting rubble would have clumped together over time, forming the moon.
The tektite and obsidian debris from such massive impacts would not last long in our solar system, or others. Solar winds and gravitational interactions tend to sweep away the dust over time, and in a few tens of thousands of years the evidence would be erased.
In the long history of our solar system, that's hardly an eyeblink. The evidence may be long gone here, but seeing what may happen when worlds collide around a nearby star shows us it's not just science fiction after all.
Credit: NASA/JPL-Caltech
• spitzer.caltech.edu
. - Наука та технологія
Amazing video once again. Keep 'em coming. thank you!
Scientifically awesome and fascinating!
THIS IS SO AWESOME!!!
Just incredible I'm at a loss for words.
thnx 4 the upload
Thank you. Great to see this. Could watch such things for hours. The universe is so much more interesting than the petty problems of our frail species.
@lazyperfectionist1
1: We measured the mass of the Earth.
2: We measured the distance of Earth/Sun using trigonometry.
3: From that we were able to deduce the mass of the Sun.
4: We measured the distance of Mercury using trigonometry.
5: From that we were able to deduce the mass of Mercury.
6: Knowing its distance we could then measure the size of Mercury.
7: Density = Mass/Volume.
Maybe not in that exact order, but that's the basics :)
Infrared astronomy is the best kind of astronomy.
Amazing.
@TheRationalizer I'm beginning to get the impression that I would need to take a few courses to understand this.
AHHHHHHHH LOOKOUT!!! 4:50
Something collided with his shirt....good vid
@RogerWazup007 The universe is 13.75 billion years old; about 3 times as old as the Solar system, so there was plenty of time for supernovae to enrich the interstellar medium with heavy elements before the Solar system formed.
It's fairly rare for stars to collide, but collisions between planets are a normal part of the final stages of planet formation around young stars.
@hardwirecars: I might also add a few more names: Eratosthenes discovered the circumference of the earth with a very good estimate of 40,000 km where it actually is about 40,007 km, and this occurred again before Christ was born.
Seleucus of Seleucia stated that the earth was a sphere 190 BC.
@TheRationalizer Well then how did we determine the mass of Mercury?
Wait a minute. Mass and gravitation are positively correlated, which means that examing the trajectory of Mercury relative to the sun should enable us to make this projection using our own planet and its orbit as a frame of reference. Do I have this part right?
@TheRationalizer I wonder if you're confusing mass with volume. I can see how, if we know the volume of the sun, we can make pretty accurate projections of the volume of other objects as compared to the sun, but I don't see how that relates to mass.
@lazyperfectionist1
An orbit is established if there is a suitable balance of the combined mass of two objects against their distances. It's all to do with mass, not volume or density.
Black holes are very dense, have lots of mass, and are very small.
If we know the mass of a planet, and we know its volume, we can calculate its density.
Density = Mass / Volume
Does that help?
@Phyle9 look up "the nebular hypothesis"
@Peter5930 Ah, thanks. For some reason I confused the numbers. I remember now that our solar system is about 4.5 billion years old, not the universe.
@j4pan You've answered your own question.
Don't forget that our galaxy is on a collision course with andromeda. That should simplify the, rather obvious, answer.
dang that is scary
where is that moon creation video i must have it.
Yes, yes it is.
@lazyperfectionist1
We know the mass of the Sun so therefore based on Mercury's distance from the Sun we know Mercury's mass too. We know the size of Mercury so we also know its density.
I liked that you liked his comment
@LilFaerl I'm sorry, I'm just learning to talk to creationists. Correct me if you would, please. It seems that they aren't moved very much by hard science and probability. Just check out some of the creationists on UA-cam. Instead it is often more effective to communicate ideas in the context of their beliefs, which is what I attempted.
@handplanty Thats makes you more patient than me. It's difficult to make an argument to a person who wants to believe. :)
you know, when it comes to usual videos on youtube, you have your idiots, and very few people that actually know what they are talking about. Most of the people who comment on these videos however, usually have a sense of logic and knowledge, which is nice :P
How do they know that Mercury is more dense?
Steve Nash men!
@bv90andy Understood, but a literal collision, which is probably not predicable given the distances involved, wouldn't be necessary to destroy life. It would require `only' a change in the gravitation forces as the planets move close enough to disrupt the balance of the orbits in our own galaxy. That could easily (probably) result in earth moving closer to, or farther away from, our sun. Whether we boil or freeze is moot. Life on earth still perishes.
Isn't it really rare for planets and stars to collide? They're so far apart, unlike the cluttered small debris that constantly collides with planets.
And our sun is 4 1/2 billion years old? I thought our solar system wasn't first generation but rather the result of previous star deaths that allowed for all the minerals we have?
If I'm wrong someone let me know.
This is called "known universe" on tv
nice shirt goober
I don't want to argue theology with you or anyone else. Nuff saideth.
looks like an ink bottle collided with his shirt.
peace,lardo.
1) I never mentioned theology; you must be confusing my reply another. 2) Why would I have any reason to contact you again?
@bv90andy Oh, of course. I was making the point that the specifics of which particular part of the `unintelligently designed' universe will kill us all first are moot. I wasn't sure if you were trying to defend the `it's a perfect design' nonsense - obviously you know better than that ;o)
@hardwirecars: Now, I wonder why the Old Testament describe earth as flat in three different verses?
Namely, 4:10-11 “saw a tree of great height at the centre of the earth...reaching with its top to the sky and visible to the earth's farthest bounds.”
So a tree standing straight could be seen from the farthest reaches of earth? Thats impossible in a spherical earth (obviously) but a flat earth could have a tall tree visible in every region.
Also the center of the earth is not on the surface.
@handplanty you mean he made the mistake even thugh he isomnipotent and omniscient....thats impossible, he can fix it in a flick
@handplanty I want you to think about this for more than a minute. The Chinese scrolls have 3,500 years up on the bible. They had a civilization of scholars who had literature, a sun dial, and rulers while the tribes of the desert were throwing stones at each other. Which do you choose to follow? The bible, describing tribes 3,500 years AFTER Chinese culture had already established itself and were living in peace and technology... Or accept that barbaric tribal people of the desert?
@j4pan
God blows up civilizations for fun.
@handplanty fucking thank you!!! in the first paragraph, that's what i've been telling people all along!! im glad someone shares my way of seeing things =D
when it comes to religion, god, and people believing in it, i have no mercy though. they are simply lying to themselves, and being deceived by a human made story, instead of opening their eyes. i used to be VERY religious when i was a kid only because i didn't know better.
@j4pan "makes no sense"--- Not to the terminally deluded
@izurz
We can't actually know that God doesn't exist any more than we can know that unicorns don't exist due to the inductive nature of the way we gain such knowledge, however the possibility of a thing's existence is not evidence for its existence and as such until sufficient evidence is provided for a things existence it is most rational to lack belief in that thing, which is why most people do not believe in unicorns and many of us lack belief in God.
@spivz1020 i am probably one of the most logical people you will meet and thats why i say there has to be a God random chance can not create humans or even evolution it had to be intelligent design there were to many exact happening for random chance to have succeeded
i liked your comment
@lazyperfectionist1
Private message me and I will explain :)
Don't fret -- we ain't goin' nowhere. Doesn't the Old Testament say, "the earth abideth forever?" Believe what you want.
I could do that . . . if I shaved my chest.
it could happen somewhere else but not earth i mean why would god go through the trouble of creating us only to annihilate us in a collision ? makes no sense
@DragonCuber Sadly, imaginary friends and delusion trump those pesky facts every time ;o)
The earth abideth until the sun becomes a red giant and doth expand to vaporize the earth. Endeth of story.
@j4pan The Sun's about to blow up in 5-6 billion years, but in less than 1 billion years it'll have become too hot to sustain life on earth. We'll have taken to the stars by then, I hope.
Don't forget that God made more mistakes, all of which have come to a semi-happy ending. The fruit in the Garden, his people becoming slaves, the tower of babel being built, and its consequences, the flood, Jesus to clean up all the mess, a Biblical belief does not restrain you from speculating about this.
@hardwirecars: So yeah, about your statement of the bible saying the earth was an orb and science disagreeing....yeah thats BS....science many times over in history and well before Christ or Christianity discovered and solved the mystery of the spherical earth, however, the Old Testament clearly believed the earth was not spherical.....
Good day....
@j4pan the bible in itself makes no sense, contradictions all over the place :S
@hardwirecars: I call bullshit, Pythagoras, Plato and Aristotle all came to the conclusion that the earth was a sphere and that was 300 years before Christs birth and before ANY Christian came to be or the bible written.
Your religion was not the first, no it loves to take credit though. However I believe your Bishop Isidore of Seville believed the earth was a flat wheel 800 years after the early Greek minds came to there conclusions about a spherical earth. Quite an interesting little fact.
@truvelocity As an adendum, @handplanty. I my opinion, try Chinese culture, because logic tells you that their literature has 3,500 (three and a half thousand years) up on the Bible. Their literature is more accurate, and they lived without your Jesus for thousands of years with Dynasties that made Jerusalem look like cave men.
Seriously... You need to get your head out of the dogma and open your mind.
you can wear some nice clothes if you're making a video
All of this religion talk is distracting us from the fact that the host is wearing a t-shirt from Baby Gap.