Exoplanet found… from another galaxy!!

By Phil Plait | November 18, 2010 12:01 pm

Today, astronomers announced that they have found a new exoplanet, a planet orbiting another star. Nearly 500 exoplanets have been found in the past 15 years, so what’s the big deal, you may ask?

The big deal is that this planet and star are from another galaxy!

exoplanet_art

[Artist's impression of the alien planet; click to extragalaticate.]

There is a whole lot of coolness going on here, so strap in.

sag_dwarf_streamOK, first, this planet is in our own Milky Way galaxy. The star, called HIP 13044, is about 2000 light years away, well inside our galaxy. So how do we know it’s from a different galaxy? All the stars in our galaxy orbit the galactic center, like planets orbit around a star. But many years ago, astronomers noticed that many stars in the sky have the same sort of motion as they orbit, as if they all belong to streams of stars, flowing like water in a river. Many such streams exist, and eventually astronomers figured out that these were the leftover remnants of entire small galaxies that had collided with, been torn apart, and basically eaten by our Milky Way.

HIP 13044 is part of one of those streams, called the Helmi Stream. It’s the remains of a dwarf galaxy the Milky Way tore apart probably more than 6 billion years ago. So the star and its planet formed in an actual other galaxy, one that either orbited the Milky Way or had an unfortunately too-close pass to it. Either way, wow!

extragalactic_planetAnd there’s more. HIP 13044 (labeled in the image here) is very old, being part of a galaxy that was eaten at least 6 billion years ago, if not more. And in fact, careful observations have shown that it’s in a more well-advanced stage in its evolution than the (4.5 billion year old) Sun is: HIP 13044 has exhausted its supply of hydrogen in its core, and is currently fusing helium into carbon. The Sun will be at this stage too, but not for another 6 billion years!

What this means, though, is that the star is already past its red giant stage. As it was running out of hydrogen in its core, it swelled up hugely, and the surface cooled. It may have had a diameter of a hundred million kilometers or more, so we call stars like these red giants.

That’s important because the planet found orbits the star extremely close in, only a few million kilometers from its surface. That means not only did this planet survive the red giant phase of its parent star, the star almost certainly engulfed the planet in the process.

That’s right: this planet from another galaxy also spent hundreds of thousands of years physically inside its star!

Holy wow! What a life this poor planet has had. It probably formed some distance out from its star. As it formed, it moved closer to its star as collisions with other objects and the drag it felt plowing through the disk of material from which it formed robbed it of orbital energy. Eventually, it settled into a nice, stable orbit. Then, a couple of billion years later, a huge spiral galaxy loomed in its sky. Over millions of years that galaxy drew larger, and larger, and larger, and then aiiieeeeee the planet’s host galaxy fell right into it, getting ripped apart, and forming a long, long stream of stars that flowed around the cannibal galaxy’s core.

exoplanet_gallery_teaseIf that weren’t enough, a few billion years later, the planet’s star began to swell. It filled a tenth of the sky, then a quarter, then half… and still it didn’t stop. The planet became engulfed, enveloped, as the star expanded past the planet itself. The outer regions of the star were exceedingly thin, almost a vacuum, but the effects were devastating. The atmosphere slowly started boiling off the planet, and the planet’s orbit spiraled it down toward the star’s core. Before the planet could be totally destroyed, the star ejected its outer layers, and the core settled down to fuse helium.

And now, so many eons later, here is what we see: an aged giant star, orbited by a battered, cooked planet, part of a procession of other stars torn from their galaxy.

Amazing.

[One note: I wondered briefly if it's possible this planet formed in our galaxy, around a native star, and was somehow stolen by HIP 13044 when the two galaxies collided. I thought of this because HIP 13044 is so old it doesn't have many heavy elements like iron and silicon in it, and in our galaxy we know that stars without these heavy elements don't form planets as readily as stars that do have them. But the chances of two stars passing close to each in a galactic collision are pretty low, and the odds of one of them getting close enough to steal another's planet are extremely low (not to mention physically unlikely), and the odds of the planet getting so close to the second star that it would get engulfed are essentially non-existent. So my bet is that this planet formed around HIP 13044. Having one mystery -- how it could've been born to a heavy-element-deficient star -- is much easier to swallow than the stack of mysteries you'd need to solve if you assumed it was purloined.]

The implication of this star and planet is important as well. In the early 1990s, we didn’t know how common planets were in the Milky Way. We only had ours to look at. But then in 1995, planets were found orbiting stars like the Sun, and 15 years later we can estimate than a large fraction of all the stars in our galaxy have planets. There may be hundreds of billions, trillions of planets in our galaxy. But other galaxies are way too far away to detect planets in them. We can guess the conditions there are similar to here, but in a sense that question put us where we were before 1995: we could guess, but we couldn’t know.

Now that’s changed. We know. We know planets can form around stars in other galaxies. And that means that when we broaden our view, look not out into the galaxy but out into the Universe, we can know that there are not just trillions of planets out there, but billions of trillions. Each galaxy we see may have trillions of planets, and there are hundreds of billions of galaxies in the Universe.

When I think of all the knowledge we’ve acquired over the centuries, all the amazing things we’ve learned, I have to say that perhaps the most incredible is that the Universe is packed full of planets, worlds beyond measure, too numerous to count. When we look out into the night sky, they’re everywhere. Too distant to see, yes, and certainly too distant to visit.

But they’re there.


ESO/L. Calçada; ESO and Digitized Sky Survey 2. Acknowledgment: Davide De Martin

Related posts:

- Is the Sun from another galaxy?
- Lonely galaxy is lonely. But it ate its friends.
- When a star eats its own
- Exoplanets survive their star’s fiery death. Or were they born from it…?


MORE ABOUT: ESO, exoplanet, HIP 13004

Comments (56)

  1. Mike C

    Fascinating. Thanks Phil.

  2. Ken

    Here’s a poem that I wrote last night. It’s oddly fitting to this post:

    You tell me I could live forever,
    I replied ‘Well baby, we will’
    ‘cuz when the planet’s in flames
    and all matter’s reclaimed
    we’ll rejoin the universe, whole.

  3. Dear Milky Way,
    Hey bub, I was just minding my own business. I was just crossing that intergalactic crosswalk and BLAMMO you sucked me right in. Well I hope you’re happy now. By the way, your MASS does look bigger now.

    regards,
    Smaller Innocent Galaxy
    :)

    Great stuff as always. Right now, somewhere, maybe some other intelligent life has spied our Solar system. Maybe they’re wondering if life indeed exists elsewhere. Everybody smile!

  4. Aaron

    Phil, this post is a beautifully written meditation on a phenomenal existential proof.

  5. CB

    Incredible. Herm, no, I’m credulous, so let’s just say awesome.

    Also this is good news for Earth in my opinion. I’ve heard that when our sun reaches the gas giant phase it’s possible that it will have lost enough mass that earth is still outside it, but that it might be swallowed up and, I presumed, destroyed. If our descendants are still around — or the octopodes develop a space program — it’s good to know that there’s maybe a chance the Earth could survive though it’d be as uninhabitable as any other barren rock. Still just knowing our home world could still orbiting Sol billions of years from now is a comfort. :)

  6. Is it possible that the planet formed after the red giant phase? Isn’t there a lot of building material after the star sheds it’s outer layer that could have formed a new planet?

  7. Erik

    Your last two paragraphs gave me chills. Considering billions of trillions of planets – I know Drake’s Equation is unsolvable and largely BS, but with numbers like those it almost seems like a foregone conclusion that there are other eyes than ours counting the planets along with us…

  8. Torbjörn Larsson, OM

    Wow. And wow. (Extragalactic origins, and star-engulfed mass & orbit survival. Merits one wow each.)

    Nitpick: This isn’t the first planet found in another galaxy, or at least purported to be. Here is a microlensing of an exoplanet in another galaxy. Been there, done that!? :-D

  9. Torbjörn Larsson, OM

    Drake’s Equation is unsolvable and largely BS

    Eh? It’s not the kind of equation you solve, and it’s only BS if you think you are somehow measuring actual frequencies from scant data – it is a perfectly sane ad hoc model _and_ bayesian learning model to boot. So it has a lot going for it, until better models comes around (if ever).

  10. dcwarrior

    so if our galaxy has been “eating” these dwarf galaxies, might there then be the supermassive blackholes formerly at the center of said galaxies orbiting around the galaxy?

  11. Helmut

    That means not only did this planet survive the red giant phase of its parent star, the star almost certainly engulfed the planet in the process.

    I’m not so sure about that. From the linked article:

    Setiawan and his colleagues hypothesise that the planet’s orbit might initially have been much larger, but that it moved inwards during the red giant phase.

    Any closer-in planets may not have been so lucky. “The star is rotating relatively quickly for an horizontal branch star,” says Setiawan. “One explanation is that HIP 13044 swallowed its inner planets during the red giant phase, which would make the star spin more quickly.”

    Although HIP 13044 b has escaped the fate of these inner planets so far, the star will expand again in the next stage of its evolution. HIP 13044 b may therefore be about to be engulfed by the star, meaning that it is doomed after all.

  12. CB

    Yeah, the Drake Equation is only BS if you start trying to plug in real numbers for the things we really have no idea of to “prove” that aliens don’t exist, or must exist, or are so common that if it was possible for them to exist that we surely must have seen them by now or other rot.

    Otherwise it’s just a useful tool for looking at the factors that go into figuring out the chances of life in the galaxy. Not to actually calculate it.

  13. Adrian Lopez

    “As it formed, it moved closer to its star as collisions with other objects and the drag it felt plowing through the disk of material from which it formed robbed it of orbital energy.”

    For some reason this made me think of the planet / dwarf planet dichotomy and how, under the IAU’s definition, a dwarf planet might become a proper planet simply by changing its orbit and ultimately clearing it of debris. Unless perhaps there’s something I’m missing?

  14. Nemesis

    I can’t help but think that planet’s a big phony…parading around our galaxy like it’s one of our own. Yet, I’m glad the Milky Way could get past the differences and adopt it, or it would be a lonely little fella.

  15. andy

    Talking of planets in metal-poor environments, there is also the case of a giant planet orbiting a pulsar+white dwarf binary in the Messier 4 globular cluster. Would be nice to know whether such environments can also produce low-mass planets like Neptune or Earth, or whether these giant planets actually represent the extreme mass ratio tail of the binary star formation process.

  16. John Paradox

    Hmmm… now, do I replace the GJ251 photo (artist’s conception)I have as a desktop or not?

    Also, the ‘planet inside the star’ reminds me of The Mote In God’s Eye, where the ‘jump point’ to the ‘Motie’ planet is inside the ‘atmosphere’ of a red giant, and ships are placed nearby to enforce a ‘quarantine’ of the Motie planet.

    J/P=?

  17. CB

    For some reason this made me think of the planet / dwarf planet dichotomy and how, under the IAU’s definition, a dwarf planet might become a proper planet simply by changing its orbit and ultimately clearing it of debris. Unless perhaps there’s something I’m missing?

    Nope, that’s a perfectly plausible scenario. And nothing that should bother you. We live in a dynamic universe. Stuff changes. One day our moon will get far enough away from us to get free of earth’s gravity and if it settles into a stable orbit of its own around the sun somewhere else, we may decide to call it a planet.

  18. Pshaw

    I’d like to introduce legislation banning these illegal immigrant planets and build a fence around our galaxy. Who’s with me?

  19. Matt B.

    And how would we feel if it turned out the Sun hadn’t come from the Milky Way, but from some demolished, captured dwarf galaxy?

  20. CB

    Nonsense, Sol and Earth are as Milky Way-an as Orion and apple pie.

  21. jlb

    People believe anything that they are told today. What is a fantasy today, tommorow becomes a history, and then a proof for some other fantastical concoction the day afterwards.
    Scientists love to be right, but they almost never change their story and correct themselves publicly when they are wrong. The public responds even slower than the scientists. Layer and layer of old baggage is always a part of the story.
    If the scientists were honest, and I am talking about the planets around our Sun, the widely-accepted planet model would also suggest that our planets came from somewhere else too!
    Who cares?
    Nebular theory only works as an idea when no one really examines it too much, than it can be used as a term, and an idea spoken in confidence, and with joy, while describing a proof of something else.
    Guesstimating what goes on 2000 light years away is fine, but it is only speculation based on the best evidence available at this time.
    It is impossible that computer simulations based on abstract mathematical models are always right. Men are not always right, even in the best conditions.
    ‘The Emperor’s new Clothes’ may be a children’s story but it has a lesson that much of modern science needs pay attention to.

  22. Argosian

    @16 – I thought the same thing :)

    @BA – According to the linked article:

    “The star is rotating relatively quickly for an horizontal branch star,” says Setiawan. “One explanation is that HIP 13044 swallowed its inner planets during the red giant phase, which would make the star spin more quickly.”

    Admittedly, I’m just an interested amateur, while he’s the pro and probably knows what he’s talking about, but I was under the impression that stars contracting from the red-giant phase rotated more quickly due to conservation of angular momentum, like a spinning skater pulling her arms in to spin faster, which can lead to pulsars twirling about at kilohertz frequencies. Why is it postulated that the additional mass and momentum of a few (relatively) minuscule rocky planets would have a significant effect on the star’s spin? Also, wouldn’t that small addition be greatly offset by the mass/momentum lost to ejection of the star’s outer layers during the later parts of the red-giant phase?

  23. Radwaste

    jlb: you haven’t been paying attention, that’s all. Now go play.

  24. Aleksandar

    Orbital and environmental stability over billions of years needed to create intelligent life might still be extremely extremely rare. Out of trillions of planets it is likely 99.9% are barren and sterile. Of all the remainder, even if they ever have life arise on them, they will have a gas giant migrating or a nearby star shift their orbit and end any life.

  25. Jamie

    jlb:Perhaps it’s time to put down the pipe and go read a book?

  26. This discovery is extremely fascinating; the likelihood that a planet survived being swallowed temporarily in its sun’s initial red giant phase is stunning. Probably the planet is now an infernal world, and has likely lost a lot of mass, but it’s still around at least!

    However once this star runs out of helium fuel it will swell up a second time and become even larger, and I doubt the planet will survive then.

  27. BJN

    Very cool. What’s mind-blowing to me is how much information scientists can glean from a tiny sampling of photons.

    I think your “ripped apart” language is a tad much. From your own description the smaller galaxy was stretched and distorted and collisions with or captured objects between the two systems would be very rare. I’m thinking at galactic scale it’s more like two smoke rings interacting than some kind of cosmic cheese grater.

  28. Mike

    I, for one, welcome our crispy-as-bacon-on-sunday extragalactic overlords.

  29. Jonathan

    How could a planet survive inside a star? On the one hand, wouldn’t it melt or be disintegrated by the energy of the reactions in the star? Wouldn’t there be enough drag from the gas in the star to slow its orbit, making the orbit decay toward the center of mass of the star? There seem like there could be many reasons that would make a planet engulfed by a star not survive the encounter.

  30. Steve D

    Jib #22 Nebular theory? Where have you been for the last 200 years?

    “If the scientists were honest, and I am talking about the planets around our Sun, the widely-accepted planet model would also suggest that our planets came from somewhere else too!”

    I give up. What in the Universe are you talking about?

  31. sHx

    The implication of this star and planet is important as well. In the early 1990s, we didn’t know how common planets were in the Milky Way. We only had ours to look at. But then in 1995, planets were found orbiting stars like the Sun, and 15 years later we can estimate than a large fraction of all the stars in our galaxy have planets. There may be hundreds of billions, trillions of planets in our galaxy. But other galaxies are way too far away to detect planets in them. We can guess the conditions there are similar to here, but in a sense that question put us where we were before 1995: we could guess, but we couldn’t know.

    After developing an interest in Astronomy at school, I felt frustrated for many years with the fact that while there were billions of suns and galaxies out there, we knew of the existence of only ‘nine’ planets. I used to wonder a lot whether a planet outside our solar system would ever be discovered in my life time. A lot!

    Then, sometime in 1994, I walked into the newsagent as I always did at 6 am for my “Herald”, and there I saw, across eight columns, the unforgettable words: NEW PLANET DISCOVERED. What a thrill that was! It lasted all week. Unfortunately, the confirmation came a little later, but the fact remained; the amazing discovery happened in my life-time.

    This most recent discovery is also quite amazing (and thank you Phil Plait for articulating my sentiment as well in your beautiful blog post) but it belongs to a cannibalised and digested galaxy. It somehow doesn’t have the same punch as the discovery of a planet, say, in the Large Magellanic Cloud.

    Meanwhile, I just can’t wait to see what the new Kepler mission is going to find in the neighbourhood for us in the next couple of years and, of course, what the James Webb space telescope will do in the next couple of decades.

  32. Gary Ansorge

    11. dcwarrior

    “might there then be the supermassive blackholes formerly at the center of said galaxies orbiting around the galaxy?”

    That’s a really interesting question. I too wonder what happened to its central black hole. Hope we don’t find out the hard way,,,

    22. jlb

    “Scientists love to be right, but they almost never change their story and correct themselves publicly when they are wrong.”

    It’s pretty obvious you are NOT a scientist. Do much listening to Faux Snooze?

    Every scientist knows they have to pass the ultimate test, having their data and theories hammered by their peers. It took nearly a generation for Einstein’s special theory to be validated. Relativity is STILL regularly tested for its accuracy. Nearly every physicist understands it’s just our best theory yet(for the part of the universe that is massive and highly energetic).

    Scientists are human,,,which is why the scientific method was created in the first place, to compensate for our nearly universal tendency to defend ourselves against criticism and,,,it works. This computer I’m using is pretty much proof of that.

    Gary 7

  33. nomuse

    A wandering planet from another galaxy? It’s obviously Medon. Maybe they’ll share some of their super-insulators and super-conductors with us. But no thanks on the planet-sized Bergenholms — I don’t think this civilization is quite ready for free planets.

  34. Kullat Nunu

    The planet is in an eccentric orbit… shouldn’t be possible, if it was inside the star! Maybe it interacted with another planet, now swallowed by the star?

  35. sHx

    OK. Here is a question, or some food for thought. Is there a reason why any star in the universe should be without a planet? Star formation is the same; there must be some left over material somewhere. I can help thinking that stars without planets might be the rarity rather than vice versa especially for Sun-like stars. All we need to discover them is better and more precise techniques and instruments of measure.

  36. Messier Tidy Upper

    Awesome news! I never get tired of hearing of all these exoplanetary discoveries and this one is remarkable on so many counts. Wonderful news, marvellous exoplanet! :-D

    Incidentally, there was a case of a suspected star orbiting inside a star for Betelgeuse :

    “A star inside a star. A 1986 study by three Harvard-Smithsonian astronomers gave evidence for a companion star orbiting the famous red giant [sic - its actually a supergiant.] Betelgeuse … Their data suggest that this close companion is in an elliptical orbit that dips inside the red-glowing, outermost atmosphere of Betelgeuse. In one interpretation … the companion star could be a blue-white companion of a few solar masses. Such a system could form when the red giant [sic] expands and engulfs part of the orbit of the second star: The system would last only a short time, astronomically speaking, since drag forces will cause the second star eventually to plunge far into the giant [sic] and to merge with it.

    Source : Page 36, ‘Cycles of Fire: Stars, Galaxies and the Wonder of Deep Space’, William K. Hartmann & Ron Miller, Workman publishing, 1987.

    Although I think this was rejected by later studies.

    This made the Aussie TV news too – although they used a yellow sun-like star in their animation which I’m pretty sure this star is NOT.

    @38. sHx :

    Is there a reason why any star in the universe should be without a planet? Star formation is the same; there must be some left over material somewhere.

    Yes, unfortnately there’s some good reasons why stars won’t form planets :

    If a star is extremely massive (eg. over twenty or so solar mass) it won’t live long enough for planets to form & its stellar winds (radiation) will blow away the dusty material that forms planets.

    Also if the star is extremely ancient – like those formed in a globular cluster it has long been thought that the star will have too little “metallic” (non-Hydrogen, Helium, Lithium) elements around to successfully form planets although a couple of possible counter-examples to that – incl., now, this one exist.

    Plus binary and multiple star systems can sometimes probably disrupt the existence of the protoplanetary disks making it unlikely for planets to form although again, a few counter-examples have been found showing this might not always be the case.

    There are also, if I recall right (& maybe I don’t) a couple of cases of fialed planetary systems (Zeta Leporis or Zeta Leonis maybe?) that have been detected where, for whatever reason, planets don’t seem to have formed but instead the star just has huge asteroid belts in their place.

  37. Messier Tidy Upper

    Wikipedia is my very helpful friend – turns out the asteroid belt referred to above is known around Zeta Leporis here :

    http://en.wikipedia.org/wiki/Zeta_Leporis#Asteroid_belt

    & this was, in fact, the first asteroid belt discovered around another star. :-)

    Unfortunately, it seems this asteroid belt has come at the expense of it having planets, esp. earth-like rocky ones. :-(

  38. Messier Tidy Upper

    @16. andy Says:

    Talking of planets in metal-poor environments, there is also the case of a giant planet orbiting a pulsar+white dwarf binary in the Messier 4 globular cluster.

    Indeed – that’s PSR B1620-26 b :

    http://en.wikipedia.org/wiki/Methuselah_(planet)

    Also dubbed the Genesis planet or Methuselah planet which is the oldest known exoplanet and also the only one (as far as I’m aware) that has ever been found inside a globular cluster. That’s despite several searches which seem to show the stars in globulars do NOT form exoplanets.

    Unusually too, this pulsar planet which has the lowest mass in its system is paradoxically the largest in diameter in the system having about a Jovian size radius versus the white dwarf with roughly an earth-radius and the pulsar which is about city-sized – yet by far the most massive of the three.

    @37. Kullat Nunu Says:

    The planet is in an eccentric orbit… shouldn’t be possible, if it was inside the star! Maybe it interacted with another planet, now swallowed by the star?

    Good point – I agree.

    It seems to me that if the planet spent much time inside the star the surrounding plasma and drag would have caused its orbit to circularise as well as spiral inwards. Your scenario seems to make more sense.

    @36. nomuse Says:

    I don’t think this civilization is quite ready for free planets.

    Hah! There’s no such thing as a free lunch planet! ;-)

  39. sHx

    @39 Messier Tidy Upper

    Most appreciate your reply. I feel better informed now. I did think about mentioning binary and multiple star systems but left it out for sake of brevity. So it is good that you brought them up.

    I googled the names of the stars you mentioned and found out about Zeta Leporis on a web page which says “abundant, warm dust around this star was strong evidence of a massive asteroid belt which may also indicate that planets are or have already formed in this system”. There is also a statement from a scientist saying “We believe we see either the remnants of planet formation or material that may become planets.”

    So there is still time for Zeta Leporis to grow up and get its acts together :)

    http://www.solstation.com/stars2/zeta-lep.htm

  40. Joel

    One the one hand, this is truly amazing. A star from another galaxy! I can’t get over how incredible this is. Galaxy mergers are incredible in themselves too. It’s amazing to think there are stars whizzing around out there relatively locally that were formed somewhere else entirely in the universe, let alone actual planets!

    On the other, and rather more personal hand, I feel a bit silly now and clearly have to go and do my homework on stellar evolution. I was under the impression that after a star reached the red giant phase it would then lose the outer layers of its atmosphere and end up as a slowly expanding planetary nebula around a white dwarf, not settle down again. Can anyone give em any pointers on this one?

  41. Messier Tidy Upper

    Add to that list of things (in comment # 39) that can prevent planets forming – having a nearby (ie. within a few light years) O type star or powerful supergiant with their destructive stellar winds and powerful UV light that destroys protoplanetary disks.

    Many otherwise suitable planet-hosting stars may be devoid of planets because of having such stars nearby sharing their natal stellar clusters in their formative stages. :-(

    OTOH, *without* these supermassive stars we wouldn’t be here either – because these are the ones that produced much of the elements that make us via supernovae and the subsequent stardust.

  42. The paper says:

    “Because of the long galactic relaxation timescale, it is extremely unlikely that HIP 13044 b joined its host star through exchange with some Milky Way star, after the former had been tidally stripped. ”

    I’m not quite sure what they mean by the “galactic relaxation timescale” ruling out capture of the planet. Any takers?

  43. Helmut

    @23

    The Horizontal Branch is a group of stars who’ve all been through the red giant phase and started helium fusion, so this one is faster than other stars when you take that process into account. But the swallowing planet hypothesis works just like the skater example. There’s mass at a distance, and when it’s brought closer to the axis of rotation it speed up.

    @40

    A star of this size will go through a couple red giant phases, each when it begins to exhaust the supply of the element that’s currently being fused. The first time happens after it runs low on hydrogen, then when it runs low on helium. This star has already run low on hydrogen, expanded into a red giant, and then started fusing helium and contracted back. Once it runs low on helium, then it will grow again and eject matter into a planetary nebula.

  44. MaDeR

    @22:
    “blah blah blah”
    All i see is one giant argument from incredulity and ignorance.

    @38:
    “Here is a question, or some food for thought. Is there a reason why any star in the universe should be without a planet?”
    Yes, there are scenarios where planets cannot form (for example, very energetic blue giants. Live fast, die young, goes in kaboom – and their level of radiation disperse protoplanetary disc sufficiently to not create anything significant). But it is exception. I fully except that most stars will have some planets.

  45. Chris Winter

    What impresses me most about this “interloper” star system is its extreme age. Hypothesizing from just one sample is risky, of course, but I can speculate that the early universe was not as metal-poor as we assume. If that’s the case (a big if, granted), we may find planets are not only more common than we thought, but older. Which pushes the possibility of intelligent civilizations back in time.

    “Think of such civilizations, far back against the fading afterglow of creation, masters of a universe so young that life had come only to a handful of worlds. Theirs must have been a loneliness we cannot imagine, the loneliness of gods reaching out across infinity and finding none to share their thoughts.”

    That’s one of the quotations that sticks in my mind. Kudos to anyone who knows where it comes from.

  46. Scott

    Read “How God came to be vs. the Big Bang theory” by J.S. Thompson

  47. Our Galaxy is now in the brief springtime of its life – a springtime made glorious by such brilliant blue-white stars as Vega and Sirius, and, on a more humble scale, our own Sun. Not until all these have flamed through their incandescent youth, in a few fleeting billions of years, will the real history of the universe begin.

    It will be a history illuminated only by the reds and infareds of dully glowing stars that would be almost invisible to our eyes; yet the somber hues of that all- but-eternal universe may be full of color and beauty to whatever strange beings have adapted to it. They will know that before them lie, not the milions of years in which we measure the eras of geology, nor the billions of years which span the past lives of the stars, but years to be counted literally in trillions.

    They will have time enough, in those endless aeons, to attempt all things, and to gather all knowledge. They will not be like gods, because no gods imagined by our minds have ever possessed the powers they will command. But for all that, they may envy us, basking in the bright afterglow of Creation; for we knew the universe when it was young.

    - From PROFILES OF THE FUTURE by Sir Arthur C. Clarke

  48. Messier Tidy Upper

    @ ^ Winchell Chung : Great quote. :-)

    @42. sHx : Thanks. :-)

  49. Phil wrote:

    “But the chances of two stars passing close to each in a galactic collision are pretty low, and the odds of one of them getting close enough to steal another’s planet are extremely low (not to mention physically unlikely)”

    So, would you say the odds against it are … ASTRONOMICAL?

    HAR! I kill me!

  50. Branden

    I just now started to wander around about space and time, I’m 16 years old and I’m confused on many things. For instance the big bang theory, How do we make a theory on something that happened in our universes early development.

    “The major feature of the Big Bang theory is that the universe was once in an extremely hot and dense state that expanded rapidly (a “Big Bang”). This rapid expansion caused the young universe to cool and resulted in its present continuously expanding state. According to recent measurements, scientific evidence, and observations,[2][3] the original state happened around 13.7 billion years ago (see age of the Universe),[4][5] which can be referred to as the time that the Big Bang occurred.” Source Wikipedia-

    Something that happened 13.7 billion years ago, We weren’t alive to see, hear, Or even make a theory about. How is it 13.6 something Billion years later we can make up a theory of the very thing that made us, Yet still have evidence to prove it to be true and have so many followers of it. It’s crazy to think not just about space, but how advanced the human species brain is..

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