Page 1 of 2

Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Mon Sep 27, 2021 9:39 am
by andmar74

Re: Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Mon Sep 27, 2021 3:26 pm
by Jakob
Evidence of the Dark Forest theory?

Re: Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Mon Sep 27, 2021 4:56 pm
by andmar74
"Dark forest theory": Alien hunters are out there lurking.
Why would they take out the stars? Much easier to destroy life on planets.

If there are hostile aliens in space, we are just sitting ducks. But since life on earth seems untouched for billions of years, we might be safe.
I did write a piece about Berserkers in this forum, so maybe not completely safe :-)

Re: Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Tue Sep 28, 2021 8:58 pm
by erowind
Thanks for posting this. If it’s aliens i’m leaning towards civilizations either enclosing their stars in very thick dyson swarms or outright consuming them for some reason we don’t understand.

Have the researchers tried looking at the confirmed candidates on any other light frequencies yet? Would it be possible to look for the gravitational influence of a star that should be there even if we can’t “see” it?

Does anyone know how close these stars were? Are any in our own galaxy? If so, are they far away or neighbors?

Re: Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Wed Sep 29, 2021 6:33 am
by andmar74
I will look into some of the research papers.

All of the stars should be in our Galaxy, unless it happens to be a Supernova explosion or a similar bright event.
Also worth noticing is that a star can't physically disappear, only if it collapses directly to a black hole, without a supernova. That is very rare.
There could be numerous explanations to why the star has "vanished", for example if the brightness has gone down below the threshold for detection ,or if the intrinsic motion of the star has led it to now be outside the field of view or mistaken for another star.

Re: Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Wed Sep 29, 2021 6:58 am
by andmar74
This image shows different possibilities for why a star has disappeared. Notice a star could also appear from "nowhere".

Re: Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Wed Sep 29, 2021 3:00 pm
by SerethiaFalcon
Can collusions with other galaxies also result in stars disappearing? Just curious.

Re: Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Wed Sep 29, 2021 3:55 pm
by andmar74
SerethiaFalcon wrote: Wed Sep 29, 2021 3:00 pm Can collusions with other galaxies also result in stars disappearing? Just curious.
Our Galaxy is not going to collide with another galaxy before Andromeda hits us, far in the future.

Collisions between galaxies is on timescales of millions of years, far too slow. And the stars don't collide so the galaxies moves through each other and dissolves due to gravity. When it settles down there's one big galaxy with most of the stars still there. Some of the stars have been lost to intergalactic space.

Re: Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Wed Sep 29, 2021 4:47 pm
by SerethiaFalcon
Thanks for explaining andmar 74! So, in this case, a collision with a galaxy would only have stars disappearing at a very slow rate and not in big chunks like in the case explained here. I knew we weren't expecting one for a while, but I was curious if those events cause this too. Now I know!

Re: Over 700 Stars Mysteriously Vanished In The Last 70 Years, But Why?

Posted: Thu Sep 30, 2021 6:22 am
by andmar74
SerethiaFalcon wrote: Wed Sep 29, 2021 4:47 pm Thanks for explaining andmar 74! So, in this case, a collision with a galaxy would only have stars disappearing at a very slow rate and not in big chunks like in the case explained here. I knew we weren't expecting one for a while, but I was curious if those events cause this too. Now I know!
No problem!

Maybe you have misunderstood a bit, let me try again:

We are talking about 700 stars not accounted for over a time period of 70 years. 70 years is nothing in astronomical time which means stars should be frozen in place, as seen from Earth. Only very close stars with high intrinsic motion will have a chance of moving outside the area where it was photographed.

In galaxy collisions, some stars will have their trajectory changed due to gravity encounters with other stars (and gravity from the sum of stars and stuff in the galaxies), and some will be kicked out of the galaxy. These stars we can't see because they are so far away, but even if we could, they would be frozen in place. They would not vanish!

As mentioned, the only way a star could physically disappear without a trace, is if the star collapses directly into a black hole, without a supernova. This is extremely rare and can't explain why 700 stars are gone. Stars just don't stop shining.

So you have to look at other explanations, for example if it's a variable star (there are many of those), it could be dimmer now than 70 years ago, so we can't see it. The problem here is we have really good telescopes, so the stars have to be much dimmer. Another explanation is, the "star" seen 70 years ago is not a star but a supernova. A supernova will shine really bright for a few months and then fade away.