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That's the basis of the Nemesis hypothesis [1]; that supposedly there's a star that roughly orbits the sun and causes havoc every few miillion years. However, i

That's the basis of the Nemesis hypothesis [1]; that supposedly there's a star that roughly orbits the sun and causes havoc every few miillion years. However, it's been pretty much debunked at this point [1]http://en.wikipedia.org/wiki/Nemesis_%28hypothetical_star%29 http://en.wikipedia.org/wiki/Nemesis_%28hypothetical_star%29

hasenj 12y ago
Well it doesn't have to be orbiting the sun and causing this periodically. It could've been a one time event.
tomphoolery 12y ago
Was gonna come in here to ask...will this explain Nemesis as not a recurring event but rather a one-time event caused by that trailing brown dwarf (or the star itself) flinging comets all over the place. It would also explain a lot of other crater-rich surfaces dating back to that time...
- vidarh 12y ago
  Not without time travel... This was only 70 thousand years ago.
- iwwr 12y ago
  If that's true it'd be hard to identify the responsible star since in a few million years it would be thousands of light years away and difficult to measure precise kinematics of it.
- logfromblammo 12y ago
  Given the distances involved, anything that may have had its orbit altered by this event is extremely unlikely to have struck any solid surface in our system already. It may, however, lead to some additional bombardment a few million years from now. By that time, we might have computers of sufficient power working from an astronomical catalog of sufficient completeness to reverse-propagate the catalog far enough to actually blame the passing stars for kicking out comets in our direction.
mangeletti 12y ago
The Nemesis Hypothesis hasn't been debunked.
- dragonwriter 12y ago
  > The Nemesis Hypothesis hasn't been debunked. I rather thought that Nemesis had become a fairly untenable hypothesis in light of the the facts that: (1) Insofar as there is a periodicity to extinctions to explain (what Nemesis was posited to explain), more recent analysis has shown that it is too consistent for any plausible orbit for Nemesis, and (2) A sensitive enough survey to detect stars (including brown dwarfs) within the radius of Earth in which Nemesis would have to exist has been conducted and failed to detect any such star.
  - mangeletti 12y ago
    I'm not sure I understood point #1. Do you mean that the periodicity is too consistent to support the theory of an orbiting body, because an orbiting body would have a less consistent orbit? If so, that's very interesting. Pertaining point #2, I'm not very confident in any empirical data observed at this point in human evolution. It's not to say that scientists aren't working very hard to learn things, but moments like http://www.theguardian.com/science/2015/feb/26/found-a-black-hole-12-billion-times-the-size-of-the-sun http://www.theguardian.com/science/2015/feb/26/found-a-black... tell me that we're going to go through many more "we're absolutely sure / wait, we were wrong" moments, especially when pertaining astronomy and ontology, both fields with many more unknowns than true facts.

hasenj 12y ago

Well it doesn't have to be orbiting the sun and causing this periodically. It could've been a one time event.

tomphoolery 12y ago

Was gonna come in here to ask...will this explain Nemesis as not a recurring event but rather a one-time event caused by that trailing brown dwarf (or the star itself) flinging comets all over the place. It would also explain a lot of other crater-rich surfaces dating back to that time...

vidarh 12y ago
Not without time travel... This was only 70 thousand years ago.
iwwr 12y ago
If that's true it'd be hard to identify the responsible star since in a few million years it would be thousands of light years away and difficult to measure precise kinematics of it.
logfromblammo 12y ago
Given the distances involved, anything that may have had its orbit altered by this event is extremely unlikely to have struck any solid surface in our system already. It may, however, lead to some additional bombardment a few million years from now. By that time, we might have computers of sufficient power working from an astronomical catalog of sufficient completeness to reverse-propagate the catalog far enough to actually blame the passing stars for kicking out comets in our direction.

mangeletti 12y ago

The Nemesis Hypothesis hasn't been debunked.

dragonwriter 12y ago
> The Nemesis Hypothesis hasn't been debunked. I rather thought that Nemesis had become a fairly untenable hypothesis in light of the the facts that: (1) Insofar as there is a periodicity to extinctions to explain (what Nemesis was posited to explain), more recent analysis has shown that it is too consistent for any plausible orbit for Nemesis, and (2) A sensitive enough survey to detect stars (including brown dwarfs) within the radius of Earth in which Nemesis would have to exist has been conducted and failed to detect any such star.
- mangeletti 12y ago
  I'm not sure I understood point #1. Do you mean that the periodicity is too consistent to support the theory of an orbiting body, because an orbiting body would have a less consistent orbit? If so, that's very interesting. Pertaining point #2, I'm not very confident in any empirical data observed at this point in human evolution. It's not to say that scientists aren't working very hard to learn things, but moments like http://www.theguardian.com/science/2015/feb/26/found-a-black-hole-12-billion-times-the-size-of-the-sun http://www.theguardian.com/science/2015/feb/26/found-a-black... tell me that we're going to go through many more "we're absolutely sure / wait, we were wrong" moments, especially when pertaining astronomy and ontology, both fields with many more unknowns than true facts.