Not dead yet
Maybe star formation is stopped, but most stars are small and have very loooooong lives, often much longer than the current age of the universe.
So those galaxies aren't dead, they're just resting.
Astroboffins think they have one of the oldest murder mysteries in the universe: what kills galaxies, and how does it happen? A study just published states that the primary cause of galactic death is strangulation – a process in which the galaxies' supply of materials needed to form new stars is choked off. There are at least …
Maybe star formation is stopped, but most stars are small and have very loooooong lives, often much longer than the current age of the universe.
It pretty much means the same thing since even the brightest red dwarves are very dim - less than 10% the luminosity of the Sun - we can't see them over intergalactic distances. Bear in mind that even the closest star to us in the night sky is completely invisible to the naked eye and difficult to identify even with a good amateur telescope.
"Bear in mind that even the closest star to us in the night sky is completely invisible to the naked eye and difficult to identify even with a good amateur telescope."
Alpha Centauri is the closest star to us and is the third brightest star in the southern sky. Not invisible to the naked eye!
Alpha Centauri is the closest star to us and is the third brightest star in the southern sky. Not invisible to the naked eye!
It's generally (but not universally) accepted that the Alpha Centauri system is the closest to Earth but the nearest known star is Proxima Centauri - the debate is whether it is part of the Alpha Centauri system, not in the distances. At magnitude 11.05 it is also around 100 times too faint to see naked eye.
"And here I thought the closest star was visible whenever my part of the earth was facing it.. assuming there weren't any clouds in the way."
Fiona wrote:
"Bear in mind that even the closest star to us in the night sky is completely invisible to the naked eye and difficult to identify even with a good amateur telescope."
The *night* sky. The Earth is not facing the Sun at night.
"If your body stopped being able to produce new cells, you wouldn't die instantly, but you wouldn't be alive very long either."
It's a horrible way to die. It's called being a walking ghost I think?
Imagine if all your DNA was removed.
They think the symptoms might be like these
https://en.wikipedia.org/wiki/Acute_radiation_syndrome
https://en.wikipedia.org/wiki/Paraquat#Toxicity
https://en.wikipedia.org/wiki/Destroying_angel#Toxicity
Your cells don't stop dividing just because you're an adult. Very roughly there are 37 trillion (million million) cells in adults, and according to Wikipedia, "Between 50 and 70 billion cells die each day due to apoptosis in the average human adult."
37000000000000 / 60000000000 = 616 days.
So except for nerve cells, most of your body is less than two years old in terms of new cell division. That's a major reason why we keep changing as we age, alas.
A typical lifespan for a human red blood cell is around 30 days. If you lost the ability to produce new cells, that would be your lifespan too.
Back on topic, if a galaxy stops producing new stars, it will lose all its bright stars within a few million years and all its main sequence stars within a few billion. After that it will be left with only red dwarfs and be a dim ember of its former self.
Anyone supplied a Tibetan monastery with an Automatic Sequence Computer lately?
We seem to get a lot of these "ah-ha" momemnents, that, when looked at a second time are simply a plot fix in the unwritten book of everything...
Simply combine Deus ex Machina with the Anthropic Principle and you get the current 'Big Bang' view of the universe...
IMHO= the 800 Pound Gorilla in the room is simply= what is Hydrogen, and, how is it apparently being formed ?? Hydrogen or lack of it seems to be the basic problem of everything...
caveiat= i am a Buddhist techno historian... RS.