Is it possible for a star to enter our solar system?

There’s been a lot of buzz in the past several months regarding Comet Elenin, a.k.a. C/2010 X1, which was discovered by Russian astronomer Leonid Elenin on December 10, 2010. Elenin is a long-period comet, which means it has a rather large orbit around the Sun… it comes in from a vast distance, swings around the Sun and heads back out to the depths of the solar system – a round trip lasting over 10,000 years. During its current trip it will pass by Earth on October 16, coming as close as 35 million km (22 million miles). Yes, 22 million miles. That’s pretty far. Way too far for us to be affected by anything a comet has to offer. Especially a not-particularly-large comet like Elenin.

Some of the doomy-gloomy internet sites have been mentioning the size of Elenin as being 80,000 km across. This is a scary, exaggerated number that may be referring to the size of Elenin’s coma – a hazy cloud of icy particles that surrounds a much, much smaller nucleus. The coma can be extensive but is insubstantial; it’s akin to icy cigarette smoke. Less than that, in fact… a comet’s coma and tail are even more of a vacuum than can be reproduced in a lab on Earth! In reality most comets have a nucleus smaller than 10km…that’s less than a billionth the mass of Earth (and a far cry from 80,000 km.) We have no reason to think that Elenin is any larger than this – it’s most likely smaller.

http://www.universetoday.com/86421/comet%E2%80%A6

It is possible for another star to enter our solar system, or at least pass nearby. The chances of such an event are somewhere between slim and none. The star system that's nearest to us right now is about 4.5 light years away, meaning that if for some reason it began moving towards us near the speed of light, which is impossible, it would still take it about 4 years to get here.

Elenin is just a plain ol' comet. There are billions of comets in and around our solar system. Some of them move inward toward the sun and pass relatively close to Earth. Some comets have struck Earth in the past, and will do so in the future, but Elenin definitely will not. Elenin will pass fairly close to Earth, but there's no way it can trigger earthquakes or any other events on our planet because it simply doesn't have enough mass to do so, no matter how it may momentarily align with other solar system bodies.

There are millions of objects in the Oort cloud and the Kuiper belt at the edge of the solar system. Occasionally one of these gets perturbed into an orbit that approached the sun. These are called comets. At any time there are several comets that come closer to the sun than earth. Except for a direct collision, comets are too small to affect a planet.

Larger extra-solar bodies (planet to sun sizes) exist but none have been detects near the solar system. A rogue sun would probably be detected much more than 10 lights away. It would probably take more than 100 years for one to reach the solar systems. A rogue planet would probably be detected before it reached the Oort cloud since it would affect the orbits of of comets.

On Oct 16 the Elenin comet will approach earth at distance of about 21 million miles. This is about the same distance as Venus at its closest approach to earth.The diameter of Elenin is about 4km. Its mass is probably less than 1/10,000,000,000 of that or Earth. Elenin may put on a spectacular light during October but not otherwise affect earth.

First off, a comet and a star are VERY different things. A comet is a small snowy dirt ball that sublimates it's stored frozen gases as it approaches a heat source (like a star). A star on the other hand is a huge orb of gases that are so dense that nuclear fusion occurs.

There is currently only one star in our solar system. It's the one you can see during the day (the big yellow ball in the sky that gives light and seems warm). However, there are millions of snowy dirt balls careening through our solar system, but I can't for the life of me find any indication of a super massive cometary body passing close to Earth on March 11. In fact, had such an object actually zipped by Earth on March 11 (with a second pass in September/October) you'd be hearing it from other, more credible sources than your friends. Stick to actual sources of knowledge when you are presented with the improbable.

And the March 11, 2011 doomsday prediction originated from a nutjob that claimed "HE" had divine information given to him by Jesus. Problem is, when his day of judgment passed, he got mad because he didn't get taken up with all the true believers, so he re-calculated the numbers Jesus told him and he came up with a new October 2011 Judgment Day (just in case Jesus forgot he was supposed to go with them).

I hope this helps. Good luck

Elenin is a comet. Its gravitational effect upon the Earth is negligible.

If a star were headed for our solar system, we'd have a lot of warning.

I can imagine that in September and October, we will have a lot of questions from the pants-wetting scientifically-illiterate drama queen community in a redux of the Harold Camping's May 21 Rapture. There will probably also be a natural disaster of a decidedly normal sort sometime close to that (given the regularity with which the Earth is afflicted with them), which will set them into an even bigger tizzy.

Possible yes, likely no. This "elenin" you heard of, you confusing is with a body named Nibiru. This is pseudoscience work of Stitchen. He claims there is a long legend behind all of this as well, causes earth quakes, magnetic poles shifts etc. But however, there is no ACTUAL physical evidence behind it. For a body merely entering our solar system to cause stuff to happen on earth would have to massive...like HUGE black hole massive. So far none of those are around us. So, fear not, there is nothing out there other than small planets and dust. Elenin is just a comet, like Haley Comet.

Comets and meteors fly by the Earth and other planets all the time, they're always in some kind of "alignment". Comets come from the Kuiper Belt, which lies outage of the orbit of Neptune and Pluto, and are constantly traveling deeper into the solar system, as all comets have a tendency to do. Unless they were to actually impact the Earth, these have absolutely no effect on the planet.

Stars revolve around the galaxy in paths disrespective of each other, sort of like cars that can't see each other. However, there is a lot of space between stars, which is fortunate for us. If our sun were the size of a marble (1 cm across), just the nearest star to us would be another marble 180 miles ways. The solar system itself would only be the size of a football field. This makes it very unlikely for one solar system to wander into another, although it's possible. It hasn't happened to our own within the last 5 billion years, so I wouldn't worry about it for the next few million.

I don't know what was wrong with the answers you got before. Asking again won't change them.

It's not possible for a star to enter our solar system without us having hundreds of thousands of years warning.

Elenin is a comet.

At its closest it will have less than 0.000000000000001 times the tide raising force of the Moon (yes, that's the correct number of zeros).

It's not possible for such a tiny object to cause earthquakes.

It will be at its closest in October, not September.

21 million miles is not 'super close' or even 'close'.

It hasn't caused any 'trouble' and it won't do so in the future.

Got it now?

If there was another galaxy crashing into ours, perhaps on the other side of The Milky Way and maybe where The Large Magellanic Cloud came from, then another star could collide with The Sun, but since a Galactic Year is around 225 million years it's not something to worry much about. Stars do seem to smash into each other though, or in theory anyway...like so -

http://www.youtube.com/watch?v=ow9JCXy1QdY