Alien Star paid us a visit

Rubecula

A lucky miss?

http://www.bbc.co.uk/news/science-environment-31519875

2 stroke

or a seeding of intelligent life?

Calibos

Thread disappoints. I thought this was going to be about John Hurt visiting a Dublin Astronomical Soc meet up or something.

JupiterKid

Interesting. I do wonder if a closer pass by other stars triggered the mass extinction of the dinosaurs at the K-T boundary 65 million years ago?

Also, this technique might someday be able to determine where our own Sun was formed and its sister stars from the same nebula.

dbran

Some of the recently discovered kuiper belt objects have peculiar orbits which cannot be explained given the current planetary set up. So I suspect that it is quite likely that over the last 4.5 billion years of the solar system the sun has had even closer encounters with other stars.

However the fact that the outer planets are in circular orbits means that none of these encounters have not been close enough to the solar system to have caused any perturbations over a very significant time.


dbran

irishgeo

dbran wrote: »

Some of the recently discovered kuiper belt objects have peculiar orbits which cannot be explained given the current planetary set up. So I suspect that it is quite likely that over the last 4.5 billion years of the solar system the sun has had even closer encounters with other stars.

However the fact that the outer planets are in circular orbits means that none of these encounters have not been close enough to the solar system to have caused any perturbations over a very significant time.


dbran

Our galaxy is odd in having one only star most have 2. Somme people think a star that didn't make it is still out there bust just reflect any light at all.

ThunderCat

irishgeo wrote: »

Our galaxy is odd in having one only star most have 2. Somme people think a star that didn't make it is still out there bust just reflect any light at all.

I'd imagine towards the galactic centre there are many double star systems due to the density of stars there. Out in the suburbs where the sun is I think our solar system is fairly typical of the other solar systems in this part of the galaxy. You only have to look through your binoculars or telescope to see that the night sky around us contains far more single systems than doubles.
What our solar system does seem to do differently however is have it's gas giants in the outer reaches of the solar system. A lot of the exo planets discovered seem to have their gas giants in close proximity to the star, with one of the gas giant exo planets discovered as having an orbital period of only 4 days if I remember rightly.

Maximus Alexander

ThunderCat wrote: »

What our solar system does seem to do differently however is have it's gas giants in the outer reaches of the solar system. A lot of the exo planets discovered seem to have their gas giants in close proximity to the star, with one of the gas giant exo planets discovered as having an orbital period of only 4 days if I remember rightly.

This is an observation bias though, no? It's a lot easier to detect a large planet in close via the transit or radial velocity method.

ThunderCat

Maximus Alexander wrote: »

This is an observation bias though, no? It's a lot easier to detect a large planet in close via the transit or radial velocity method.

Yea spot on there. I suppose I should have said that our solar system appears different compared to a lot of the others we have so far identified, which as it stands is such a small number of the total number of star systems in our galaxy that it doesn't mean much at all at this stage.

Rubecula

If susch a star did pass by it makes me wonder if it had some effects. Planets moved around ... a suspected outer planet thrown out of the solar system all together ... heavy bombardment of the planets etc.

Lovely Bloke

The best part of that article is this sub-headline

Grand theft Oort-o?