6 ms·

Asteroid that cohabits an orbit with Jupiter came from outside the solar system

67 points by digital55 8y ago

seren 8y ago
Does the fact we can find objects from others systems increases the likelihood of panspermia ?
- kekebo 8y ago
  Can't find a sound source right now[1] but reportedly some mushroom spores are able to make it into space and withstand its conditions. Edit: thus the more extraterrestrial material makes it to earth the higher the chances that biological material able to withstand the transport conditions makes it here as well. [1] https://www.dopemagazine.com/spores-in-space/ https://www.dopemagazine.com/spores-in-space/
  - mmjaa 8y ago
    Tardigrades have been demonstrated capable of surviving in space for extended periods and withstanding extreme conditions. http://www.bbc.co.uk/nature/12855775 http://www.bbc.co.uk/nature/12855775 Then there is the whole recent "Octopus RNA too weird for Earth" thing, which is setting alight the panspermia theses .. myself, personally, I'm tending to think its more and more likely. In my head, in 10 years time, we'll all have this gigantic "there is life in space, and its just like here on Earth only .. hardier .." discussion again and again. Or, maybe we'll still be wondering .. either way, my mind is made up: Octopus are galaxy-wide species, tardigrades too, and we monkeys better be careful we don't join the rest of whatever bipedal species are out there, and step on too many of our little tardigrade/octopus buddies. And, so on. (BTW, don't eat octopus! If the aliens invade, they'll probably massacre you eaters first!)
- jcims 8y ago
  I think so. Four billion years doesn't seem like enough time to evolve the the sophisticated encoding mechanism of DNA and the level of complexity in individual organisms and the interdependencies they have on each other. I really wish I could find a sort of statistical breakdown of the odds of this all working purely by chance (I'm definitely a fan of evolution and i'm not necessarily invoking woo or God here, just thinking that there are mechanisms at play we don't understand, and a head start would explain a lot for me) This is how my hopelessly naive mind thinks about the problem: Let's round up to say there is 10^15kg of biomass on the planet[1], and there are 10^12 cells per kg[2]. Let's assume that those cells have reproduced every hour for the last 4 billion years (or 35x10^12 hours). That's ~35x10^39 opportunities to pass evolved genetic material to the next generation of cell. One of the organisms with the simplest known genome is mycoplasma genitalium[3], with ~588 genes expressed over 580,070 base pairs. Each base pair has four possible configurations (A,C,G or T). I don't know much of anything, and I definitely don't know the rules around how the base pairs come together. I'm going to naively assume that these base pairs can come together any way they like, and that mutations in DNA express themselves as changes in these sequences. This leaves the DNA of mycoplasma gentalium with 4^580070 or 8.7*10^349236 possible configurations of their DNA. Obviously only a small portion of those are viable. But how do you get from nothing to something of the complexity required to reproduce, and then how do you get from something of that level of simplicity to the genetic diversity that we have on the planet. How many generations from the first living organism are there to current people. Let's say it's a trillion generations. How does random mutation bring you from say a half a million base pairs at the beginning to 3 billion finely tuned base pairs[3] at the end? It just doesn't seem like enough time to me. 1. https://en.wikipedia.org/wiki/Biomass_(ecology) https://en.wikipedia.org/wiki/Biomass_(ecology) 2. https://en.wikipedia.org/wiki/Cell_(biology) https://en.wikipedia.org/wiki/Cell_(biology) 3. https://www.saylor.org/content/BIO_Kimball/users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/GenomeSizes.html https://www.saylor.org/content/BIO_Kimball/users.rcn.com/jki...
  - auntienomen 8y ago
    Nature doesn't use arbitrary random sequences of base pairs, any more than we use random sequences of English letters. We can make them, of course, but that's as meaningful as 'bthdkekd'. I am not sure we know enough about the correlation structure of the DNA code to do the calculation you propose.
    - jcims 8y ago
      In a way it is arbitrary, because anything else would imply meaning or intent. Mutations are, as far as we know, arbitrary. Your last point is the thing that has stymied me to date. What is the range of mutation that would allow for a successful offspring and convey (mal)adaptive changes.
      - auntienomen 8y ago
        I use 'arbitrary' in the sense of uniformly random. The point is it's not uniformly random. You can think of reproduction as a random walk in the space of DNA combinations, but it's not a uniform random walk. It has a structure that comes from the biochemical processes which perform the recombinations of DNA. Focusing on mutations ignores this point. (Also, as an aside, it's not settled that mutations occur at random positions. That may be a reasonable starting point, but it's likely that the way DNA folds into nucleosomes/chromatine/chromosomes biases the location of mutations.)
  - plopilop 8y ago
    I'm not a biologist, but I'd be surprised that genetic reproduction would be as stable 3 billion years ago than now. I would not be surprised that monocellular beings, which don't need DNA replication to survive, had a more defective cloning system, thus more subject to whichever DNA replication bug. Plus, life took about 1 billion years to emerge. This is huge. The solar system took about the same time to form. Also, life may be extremely slow to appear, but once it's there, progression is quicker. Since the beginning of phanerozoic eon (and Cambrian explosion), a geologic period (Pleistocene, Jurassic, Cambrian...) only lasts a few tens of millions years. I find it very plausible that at the beginning of Cambrian era, a critical step in evolution was reached, allowing a better and faster evolution.
flukus 8y ago
Why is originating outside the solar system the only explanation for a retrograde orbit? Couldn't a close encounter or several with other bodies reverse it's direction around the sun?
- zeristor 8y ago
  I imagine the probability of that happening would be less than capturing a wandering body.
- SideburnsOfDoom 8y ago
  > Why is originating outside the solar system the only explanation for a retrograde orbit? From TFA: > “But at the beginning of this investigation, we did not suspect BZ to be of interstellar origin,” he explained. “We developed a new method that allows us to follow the asteroid back in time to see which part of the solar system it came from.” > But as far back as they could trace the jigsaw parts of the solar system — rocks and planets swirling and mixing — all the way to its birth, 4.5 billion years ago, BZ kept going around the same wrong way. Which meant the asteroid could not have been part of the swirling cloud of dust and gas from which the sun and planets originally condensed so long ago. In other words: in simulation runs, extrasolar was the only explanation for this retrograde orbit.
  - slavik81 8y ago
    That sounds a bit like starting with a smoothie and running the blender in reverse until the starberries put themselves back together. The n-body problem is chaotic and 4.5By is a long time. It's incredible. edit: The actual paper is very readable and very interesting. Props to the NYT for linking it.
    - richmarr 8y ago
      It's more like putting berries into the blender and running it to see how often a berry hits you in the eye. They found that coplanar planets and coplanar debris statistically won't produce this specific type of (high inclination) orbit.
zeristor 8y ago
what sort of delta V would a probe need to shadow it? Perhaps a Jupiter, solar transfer orbit could help...
- deleted 8y ago
  [deleted]
- ahje 8y ago
  From what I can tell from the animation in the article, it shouldn't be that far out. I'm not an astronomer or anything, but from my point of view, it would be quite interesting to find out more about that asteroid's composition etc.
  - TeMPOraL 8y ago
    It's not about how far out they are, but how fast they are going relative to Earth. When you're trying to get to something in space, you need to roughly match both positions and velocities between you and your target.
    - Cthulhu_ 8y ago
      I did a quick googling, the earth's orbital speed is 29.78 km/second, so you'd need to cancel that out first, then speed up again to match the speed of the asteroid. For comparison, you need 9.4 km/s of delta-V to bring something in low earth object (7.8 km/s for orbit, plus 1.3-1.8 km/s for atmospheric and gravity drag). To put something in counter-rotating low earth orbit, you probably also need to add the rotation speed of the earth (at the location of launch), but, I don't know the figures there (not a three second googling away). So uh, yes. Needs a rocket with at least four times as much delta-V as what we currently use to put something in orbit. I'm reading the New Horizons project, which up until now was the fastest thing to leave Earth, was shooting away from us at 16.26 km/s - all from chemical thrust. The Voyager 1 is still going a bit faster thanks to gravity assists.
- sathackr 8y ago
  Probably a bunch. I'm not a rocket scientist, but Google tells me Jupiter's orbital velocity is about 13,000 m/s, with Earth's velocity being about 30,000 m/s. If my KSP-taught understanding of orbital mechanics is correct, you'd first have escape earth's gravity(~13,000m/s), then reverse your orbital velocity(about 60,000m/s, also matching the orbital plane of the asteroid in the process), and then do a standard hohmann transfer to the asteroid orbit(looks like about another 5,000m/s) just to get to the asteroid, but then you have to cancel the closing speed. I don't know enough to know how to calculate the approach velocity but looks like it might be a bunch. Chart showing d/v required to reach various objects in our solar system: https://i.imgur.com/WGOy3qT.png https://i.imgur.com/WGOy3qT.png
saintPirelli 8y ago
TIL the euphamism "cigar shaped" when something clearly looks like a turd.
teekert 8y ago
Ok, ok , it's going to be hard to get used to but maybe, over time I can accept them and find rest again.
roryisok 8y ago
Three space stories on the front page today. Makes me happy
deleted 8y ago
[deleted]
aaron695 8y ago
This shit just does not seem possible. How many 10000000000's of billions of asteroid's from nearby solar systems must be being popped out of each one for asteroid's to hit our solar system. Space is just a empty void, with trace amounts of basically nothing, how can things be hitting each other? It seems impossible. But we seem to be claiming it's daily, given so far we've claimed to have found 2? If it's real, what does it really mean?
bediger4000 8y ago
Jupiter's orbit is fairly circular (eccentricity about 0.05). How does an extrasolar obeject get captured into such an orbit? I read somewhere that in-system asteroids could be captured into circular orbits (Phobos, Demos at Mars, lots of moons of Saturn and Jupiter) if they're originally half of a binary asteroid. The other half gets kicked away to circularize the remaining half's orbit. That doesn't seem like something that could happen to put an object into retrograde orbit around the Sun.
- Scaevolus 8y ago
  "Here we show that irregular satellites are captured in a thin spatial region where orbits are chaotic , and that the resulting orbit is either prograde or retrograde depending on the initial energy. Dissipation then switches these long-lived chaotic orbits into nearby regular (non-chaotic) zones from which escape is impossible. The chaotic layer therefore dictates the final inclinations of the captured moons" http://sci-hub.tw/10.1038/nature01622 http://sci-hub.tw/10.1038/nature01622
- bediger4000 8y ago
  I found this: http://www2.esm.vt.edu/~sdross/papers/borum-et-al-2012-report.pdf http://www2.esm.vt.edu/~sdross/papers/borum-et-al-2012-repor... It reads as I remember, but the diagrams are better than I recall. Maybe there is another paper out there with less cool diagrams on this topic.
zeristor 8y ago
Wouldn’t there be as many alien asteroids orbiting in the same direction as against it? I imagine there should be a few alien asteroids amongst the current contingent. I take it isotopic Analysis can only be done with a sample. There are energy level differences in isotopes though...

67 points by digital55 8y ago

seren 8y ago

Does the fact we can find objects from others systems increases the likelihood of panspermia ?

kekebo 8y ago
Can't find a sound source right now[1] but reportedly some mushroom spores are able to make it into space and withstand its conditions. Edit: thus the more extraterrestrial material makes it to earth the higher the chances that biological material able to withstand the transport conditions makes it here as well. [1] https://www.dopemagazine.com/spores-in-space/ https://www.dopemagazine.com/spores-in-space/
- mmjaa 8y ago
  Tardigrades have been demonstrated capable of surviving in space for extended periods and withstanding extreme conditions. http://www.bbc.co.uk/nature/12855775 http://www.bbc.co.uk/nature/12855775 Then there is the whole recent "Octopus RNA too weird for Earth" thing, which is setting alight the panspermia theses .. myself, personally, I'm tending to think its more and more likely. In my head, in 10 years time, we'll all have this gigantic "there is life in space, and its just like here on Earth only .. hardier .." discussion again and again. Or, maybe we'll still be wondering .. either way, my mind is made up: Octopus are galaxy-wide species, tardigrades too, and we monkeys better be careful we don't join the rest of whatever bipedal species are out there, and step on too many of our little tardigrade/octopus buddies. And, so on. (BTW, don't eat octopus! If the aliens invade, they'll probably massacre you eaters first!)
jcims 8y ago
I think so. Four billion years doesn't seem like enough time to evolve the the sophisticated encoding mechanism of DNA and the level of complexity in individual organisms and the interdependencies they have on each other. I really wish I could find a sort of statistical breakdown of the odds of this all working purely by chance (I'm definitely a fan of evolution and i'm not necessarily invoking woo or God here, just thinking that there are mechanisms at play we don't understand, and a head start would explain a lot for me) This is how my hopelessly naive mind thinks about the problem: Let's round up to say there is 10^15kg of biomass on the planet[1], and there are 10^12 cells per kg[2]. Let's assume that those cells have reproduced every hour for the last 4 billion years (or 35x10^12 hours). That's ~35x10^39 opportunities to pass evolved genetic material to the next generation of cell. One of the organisms with the simplest known genome is mycoplasma genitalium[3], with ~588 genes expressed over 580,070 base pairs. Each base pair has four possible configurations (A,C,G or T). I don't know much of anything, and I definitely don't know the rules around how the base pairs come together. I'm going to naively assume that these base pairs can come together any way they like, and that mutations in DNA express themselves as changes in these sequences. This leaves the DNA of mycoplasma gentalium with 4^580070 or 8.7*10^349236 possible configurations of their DNA. Obviously only a small portion of those are viable. But how do you get from nothing to something of the complexity required to reproduce, and then how do you get from something of that level of simplicity to the genetic diversity that we have on the planet. How many generations from the first living organism are there to current people. Let's say it's a trillion generations. How does random mutation bring you from say a half a million base pairs at the beginning to 3 billion finely tuned base pairs[3] at the end? It just doesn't seem like enough time to me. 1. https://en.wikipedia.org/wiki/Biomass_(ecology) https://en.wikipedia.org/wiki/Biomass_(ecology) 2. https://en.wikipedia.org/wiki/Cell_(biology) https://en.wikipedia.org/wiki/Cell_(biology) 3. https://www.saylor.org/content/BIO_Kimball/users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/GenomeSizes.html https://www.saylor.org/content/BIO_Kimball/users.rcn.com/jki...
- auntienomen 8y ago
  Nature doesn't use arbitrary random sequences of base pairs, any more than we use random sequences of English letters. We can make them, of course, but that's as meaningful as 'bthdkekd'. I am not sure we know enough about the correlation structure of the DNA code to do the calculation you propose.
  - jcims 8y ago
    In a way it is arbitrary, because anything else would imply meaning or intent. Mutations are, as far as we know, arbitrary. Your last point is the thing that has stymied me to date. What is the range of mutation that would allow for a successful offspring and convey (mal)adaptive changes.
    - auntienomen 8y ago
      I use 'arbitrary' in the sense of uniformly random. The point is it's not uniformly random. You can think of reproduction as a random walk in the space of DNA combinations, but it's not a uniform random walk. It has a structure that comes from the biochemical processes which perform the recombinations of DNA. Focusing on mutations ignores this point. (Also, as an aside, it's not settled that mutations occur at random positions. That may be a reasonable starting point, but it's likely that the way DNA folds into nucleosomes/chromatine/chromosomes biases the location of mutations.)
- plopilop 8y ago
  I'm not a biologist, but I'd be surprised that genetic reproduction would be as stable 3 billion years ago than now. I would not be surprised that monocellular beings, which don't need DNA replication to survive, had a more defective cloning system, thus more subject to whichever DNA replication bug. Plus, life took about 1 billion years to emerge. This is huge. The solar system took about the same time to form. Also, life may be extremely slow to appear, but once it's there, progression is quicker. Since the beginning of phanerozoic eon (and Cambrian explosion), a geologic period (Pleistocene, Jurassic, Cambrian...) only lasts a few tens of millions years. I find it very plausible that at the beginning of Cambrian era, a critical step in evolution was reached, allowing a better and faster evolution.

flukus 8y ago

Why is originating outside the solar system the only explanation for a retrograde orbit? Couldn't a close encounter or several with other bodies reverse it's direction around the sun?

zeristor 8y ago
I imagine the probability of that happening would be less than capturing a wandering body.
SideburnsOfDoom 8y ago
> Why is originating outside the solar system the only explanation for a retrograde orbit? From TFA: > “But at the beginning of this investigation, we did not suspect BZ to be of interstellar origin,” he explained. “We developed a new method that allows us to follow the asteroid back in time to see which part of the solar system it came from.” > But as far back as they could trace the jigsaw parts of the solar system — rocks and planets swirling and mixing — all the way to its birth, 4.5 billion years ago, BZ kept going around the same wrong way. Which meant the asteroid could not have been part of the swirling cloud of dust and gas from which the sun and planets originally condensed so long ago. In other words: in simulation runs, extrasolar was the only explanation for this retrograde orbit.
- slavik81 8y ago
  That sounds a bit like starting with a smoothie and running the blender in reverse until the starberries put themselves back together. The n-body problem is chaotic and 4.5By is a long time. It's incredible. edit: The actual paper is very readable and very interesting. Props to the NYT for linking it.
  - richmarr 8y ago
    It's more like putting berries into the blender and running it to see how often a berry hits you in the eye. They found that coplanar planets and coplanar debris statistically won't produce this specific type of (high inclination) orbit.

zeristor 8y ago

what sort of delta V would a probe need to shadow it? Perhaps a Jupiter, solar transfer orbit could help...

deleted 8y ago
[deleted]
ahje 8y ago
From what I can tell from the animation in the article, it shouldn't be that far out. I'm not an astronomer or anything, but from my point of view, it would be quite interesting to find out more about that asteroid's composition etc.
- TeMPOraL 8y ago
  It's not about how far out they are, but how fast they are going relative to Earth. When you're trying to get to something in space, you need to roughly match both positions and velocities between you and your target.
  - Cthulhu_ 8y ago
    I did a quick googling, the earth's orbital speed is 29.78 km/second, so you'd need to cancel that out first, then speed up again to match the speed of the asteroid. For comparison, you need 9.4 km/s of delta-V to bring something in low earth object (7.8 km/s for orbit, plus 1.3-1.8 km/s for atmospheric and gravity drag). To put something in counter-rotating low earth orbit, you probably also need to add the rotation speed of the earth (at the location of launch), but, I don't know the figures there (not a three second googling away). So uh, yes. Needs a rocket with at least four times as much delta-V as what we currently use to put something in orbit. I'm reading the New Horizons project, which up until now was the fastest thing to leave Earth, was shooting away from us at 16.26 km/s - all from chemical thrust. The Voyager 1 is still going a bit faster thanks to gravity assists.
sathackr 8y ago
Probably a bunch. I'm not a rocket scientist, but Google tells me Jupiter's orbital velocity is about 13,000 m/s, with Earth's velocity being about 30,000 m/s. If my KSP-taught understanding of orbital mechanics is correct, you'd first have escape earth's gravity(~13,000m/s), then reverse your orbital velocity(about 60,000m/s, also matching the orbital plane of the asteroid in the process), and then do a standard hohmann transfer to the asteroid orbit(looks like about another 5,000m/s) just to get to the asteroid, but then you have to cancel the closing speed. I don't know enough to know how to calculate the approach velocity but looks like it might be a bunch. Chart showing d/v required to reach various objects in our solar system: https://i.imgur.com/WGOy3qT.png https://i.imgur.com/WGOy3qT.png

saintPirelli 8y ago

TIL the euphamism "cigar shaped" when something clearly looks like a turd.

teekert 8y ago

Ok, ok , it's going to be hard to get used to but maybe, over time I can accept them and find rest again.

roryisok 8y ago

Three space stories on the front page today. Makes me happy

deleted 8y ago

[deleted]

aaron695 8y ago

This shit just does not seem possible. How many 10000000000's of billions of asteroid's from nearby solar systems must be being popped out of each one for asteroid's to hit our solar system. Space is just a empty void, with trace amounts of basically nothing, how can things be hitting each other? It seems impossible. But we seem to be claiming it's daily, given so far we've claimed to have found 2? If it's real, what does it really mean?

bediger4000 8y ago

Jupiter's orbit is fairly circular (eccentricity about 0.05). How does an extrasolar obeject get captured into such an orbit? I read somewhere that in-system asteroids could be captured into circular orbits (Phobos, Demos at Mars, lots of moons of Saturn and Jupiter) if they're originally half of a binary asteroid. The other half gets kicked away to circularize the remaining half's orbit. That doesn't seem like something that could happen to put an object into retrograde orbit around the Sun.

Scaevolus 8y ago
"Here we show that irregular satellites are captured in a thin spatial region where orbits are chaotic , and that the resulting orbit is either prograde or retrograde depending on the initial energy. Dissipation then switches these long-lived chaotic orbits into nearby regular (non-chaotic) zones from which escape is impossible. The chaotic layer therefore dictates the final inclinations of the captured moons" http://sci-hub.tw/10.1038/nature01622 http://sci-hub.tw/10.1038/nature01622
bediger4000 8y ago
I found this: http://www2.esm.vt.edu/~sdross/papers/borum-et-al-2012-report.pdf http://www2.esm.vt.edu/~sdross/papers/borum-et-al-2012-repor... It reads as I remember, but the diagrams are better than I recall. Maybe there is another paper out there with less cool diagrams on this topic.

zeristor 8y ago

Wouldn’t there be as many alien asteroids orbiting in the same direction as against it? I imagine there should be a few alien asteroids amongst the current contingent. I take it isotopic Analysis can only be done with a sample. There are energy level differences in isotopes though...