watching star 10 million light years away. Are they gone?

[albertomichieli]

some of the stars we see on the sky are they disappeared, meaning do not exist anymore<br />only light is arriving

 

[mooware]

It's very possible that some of the stars you see are no longer there. When you look at the stars you are seeing how they used to look.<br /><br />

 

[lunatio_gordin]

yep. For all we know, Alpha centauri could have miraculously disappeared, and we wouldn't know for several more years. Heck, the sun could spontaneously disappear and we wouldn't know it for 8 minutes.

 

[lunatio_gordin]

Oh. but did you read the top Ten ways to destroy the Earth on Livescience? <img src="/images/icons/laugh.gif" />

 

[joshbe]

Think about it. Ten Billion years from now, when your great, great..............grandkids are looking at the sky, the light from the star you saw in 2005 finally reaches the Earth, and as those kids stare in awe through a 100 meter affordable telescope, The star bursts in a spectacular explosion. Yeah, it could happen.

 

[nexium]

It is unlikely any of our decendents will be alive in ten billion AD. If they are; 100 meter affordable telescopes are probable.<br /> What you ment to say (I think) is a star we watched in 2005 goes super nova, but it takes ten billion years for the light from the supernova to reach Earth.<br /> While ten billion light-years away main sequence stars are rarely observed in 2005, lots of ten million light-years away stars are observed with modest telescopes and several percent of them, left main sequence while the light was enroute, and at least 1% are not presently producing enough light to be visable even with a 100 meter telescope at a distance of 11 million lightyears, the 10% increase being due to the accelerating expansion of the Universe plus average proper movement. Neil

 

[rednet]

"It is unlikely any of our decendents will be alive in ten billion AD."<br /><br />To put this in perspective, its like a cingle celled organism swimming in a 1 billion year old earth ocean pondering the question about his decendents.... us. I think evolution will continue even after 10 billion A.D., its just hard to imagine what we will turn into by then! If we aren't able to harness energy from the sun before it dies to travel to another we will probably go back to one cell organisms and the whole process will start all over.

 

[joshbe]

Umm, suurre. I was just trying to make a story.

 

[olimatis]

A star of one solar mass remains in main sequence for about 10 billion years, until all of the hydrogen has fused to form helium. 10 million is a quite small proportion of the entire life of a star ... but statisticaly speaking, there is tiny chance to look at a star that is dead ... but the resulting dwarf will still be there for some additional millon years. If the star were massive enough (supernova), activity will continue for billion years and new stars could born in the bossom of the remnants.