Stars that do not exist anymore?

Question

I heard that Betelgeuse has already exploded. (I know about the time difference) I just wonder if it is true. Are there other known stars that no longer exist? Or that have lost their luminocity?

I understand astrophysics well. I meanl we know the distance of a star in light years. We also know (approximately) its age and how long it will take for it to become a supernova. I just wonder if there are stars that their distance in light years is more than the time left for them.

Answer 1

technically all of the stars we see could be gone already and we wouldn't know. if betelgeuse has exploded we would not know for a few centuries. we do know that it might blow up any time between now and 5000 years from now, but that hardly tells us if it is still there or not.

the physics are not accurate enough.. well the observations are not accurate enough to be able to calculate when exactly a star will die. so no one can make that assumption.

it is a possibility but it is not certain.

Answer 2

How can it be true? How could anyone know? Nothing travels faster than light, so the first indication we'll ever get that Betelgeuse has exploded is when we see it explode.

I suspect you (or whoever you heard it from) are getting confused with the common observations that a) Betelgeuse is a red supergiant, and therefore is a candidate for a supernova, and b) that stars are so far away and light takes a finite time to reach us that some of them could have exploded and we wouldn't know yet.

Answer 3

Everyone is acting like there is another way to tell other than observing it. If you are looking at something the image is just light that is finally reaching your eye. So if a star 1 light year away explodes right now, we wouldn't be able to know for another year. Even if you look through a telescope you would still be seeing the image of the star one year ago. So any image we see in space would be delayed in a time of the light traveling.

Answer 4

Understanding the theoretical nature of stars and their evolution allows us to make statements on the current "real" state of a star rather than the apparent state caused by the time light needs to travel from the star to us.
Betelgeuse grows dimer as it progresses through the red giant phase. However it still exists. To say it doesn't exist would only have meaning if it collapsed into a singularity.
While it is dimmer it has not lost all its luminocity.

Answer 5

In 1987 a blue giant exploded in the large Magellanic cloud 170,000 light years away.
The star was known to astronomers as a blue giant [sanduliac] [1987A]
If you had looked at this star in 1986 you would never have known that it blew up 170,000 years ago.

Answer 6

Some stars simply loose their luminosity. Some stars explode. Some stars turns into a black hole. It depends on their initial mass.

Our Sun for example will loose its luminosity and became a white dwarf, they expect. Stars far bigger than ours may go into super-nova (exploding star).

P.S. We actually see super-nova explosions time to time, one has observed thousands years ago, historians recorded extreme bright pulse in night skies. Otherwise we see their remnants like beautiful shiny cloud of Betelgeuse, because there are so many stars and so many of them goes to nova.
.

Answer 7

A supernova is essentially the explosion of a star in outer space. During a supernova occurrence, a star’s luminosity is increased by as much 20 times as the bulk of the star’s mass is blown away at an extremely high velocity. Supernova remnants, including the signature bright light they leave behind, can often be seen in the night sky by the naked eye for several weeks as it gradually diminishes.

There are several different kinds of supernovae, which are believed to be caused by two distinct sources. One possible cause for Supernova occurrences results from a star halting its generation of fusion energy from fusing the nuclei of atoms in its core, causing it to collapse under the force of its own gravity. Another possible source occurs when a white dwarf star accumulates material from another nearby star until it nears its Chandrasekhar limit and undergoes runaway nuclear fusion in its interior, ultimately leading to its destruction.

Supernovas are generally classified according to the lines of different chemical elements that appear in their spectra, the first of which is hydrogen. If a supernova's spectrum contains a hydrogen line, it is classified as Type II, if this line of hydrogen is not present the Supernova is Type I. Within the Type I and Type II classifications are five sub-classifications that include Type Ia, Type Ib, Type Ic, Type II-P and Type II-L, each having its own distinct chemical and physical characteristics.

hope this helps

Answer 8

we could take an occasion of a megastar this is one hundred gentle years away. It takes gentle one hundred years to get from that megastar to our eyes. So if that megastar all of sudden blew up or disappeared, we does not know for one hundred years after that 2nd. Now take the occasion of a galaxy 10 billion gentle years away. The universe is 13.8 billion years previous, so as that galaxy shaped early on. So 10 billion years in the past the gentle began leaving that galaxy and we are only now considering that historic gentle. That galaxy could have been destroyed 3 billion years in the past, yet we does not see the gentle end (or see the explosion or regardless of) for yet another 3 billion years. the gentle that left that galaxy formerly the explosion or regardless of remains traveling in direction of us. to maintain the confusion down, astronomers usually communicate over with events we see on stars or galaxies in accordance with whilst we see the form right here on earth. So if a supernova explodes interior the Andromeda galaxy (2.5 million gentle years away), we date it from whilst we observed it, no longer whilst it got here approximately 2.5 billion years in the past (that ought to easily be too confusing for each man or woman).

Answer 9

They still exist as long as we remember them

Answer 10

Well we did destroy Alderaan but that was only a planet.