Alien star system buzzed the Sun

The article links to a paywalled source for the paper &quot;The Closest Known Flyby of a Star to the Solar System&quot; by Mamajek et al. Full text is freely available on arXiv at [1].<p>[1] <a href="http://arxiv.org/abs/1502.04655" rel="nofollow">http:&#x2F;&#x2F;arxiv.org&#x2F;abs&#x2F;1502.04655</a>

For reference, 0.8 light years is about 50,000 AU. (AU = the distance from the Earth to the Sun.) Pluto is about 49 AU away.

Weren&#x27;t humans alive back 70,000 years ?<p>I wonder if one of our ancestor then gazed at the sky and saw something or not. Guess we will never know :(

I am wondering if we could predict those events, and then launch a space probe similar to Voyager I and II that would be hooked in the alien star&#x27;s gravity and orbiting around it while it travels in the Milky Way, which would be a some free speed for the space probe to explore space further.<p>Now, since stars rarely get that closed, I guess it&#x27;s a bit pointless but I am still curious about it.

I&#x27;m starting to wonder if a somewhat similar event could have occurred ~66 million years ago and triggered a series of events leading to the extinction of dinosaurs.

Not only is this super amazing, it has probably the best sub-header I’ve ever read in a science article: “Grand theft Oort-o?”

This reminds me of the story &quot;A Pail of Air&quot; [0] where a &quot;dark star&quot; passes through the inner solar system, and its gravity causes the Earth to be ejected from the Sun&#x27;s orbit. The story features a family who can only survive by maintaining a fire and constantly fetching pails of frozen Oxygen to heat up to breathe and pressurize their living area.<p>I thought of it as one of those things that&#x27;s extremely unlikely to happen, but we&#x27;d be screwed if it did.<p>A little surprising that other start passing through the outer Oort cloud might actually happen semi-regularly, on galactic timescales. Makes the idea sound a little less unlikely, though the inner Solar System seems to have been around for ~5 billion years, and hasn&#x27;t been disrupted by any star-mass galactic bodies yet.<p>[0] <a href="http://www.baenebooks.com/chapters/0743498747/0743498747___6.htm" rel="nofollow">http:&#x2F;&#x2F;www.baenebooks.com&#x2F;chapters&#x2F;0743498747&#x2F;0743498747___6...</a>

20 light years per 70000 years in miles per hour = 191604.751 miles per hour, according to google

I&#x27;m curious about what, if any, gravitational effects this would&#x27;ve had on the earth? Seems like its a relatively small star and it was so far away that I&#x27;m guessing any pull would&#x27;ve been negligible.

How visible would this have been in the night sky?

Someone should run an n-body simulation of the solar system and this star backwards in time to see if it had any perturbative effects on us. What if this star was responsible for ripping Pluto away from a planet or sending Phobos down into the inner solar system to be captured by Mars?

How long would it take for Oort objects that are nudged out of their orbit to become comets buzzing or hitting Earth?<p>Also, if that star system has its own Oort cloud, could some of the objects there have jumped system and become long-term comets?

Dealing with asteroids feels plausible.. but how to deal with a star? scary stuff

Possibly the farthest away two things have ever been from each other where the word &quot;buzzed&quot; was used to describe their proximity.