How long till the sun goes supernova?

[towjyt]

Since there is a difference between the rate at which time passes on Earth and the rate at which time passes on the Sun due to the time dialation factor, has anyone calculated how much time passes on the sun, while a year passes on Earth?

 

I have read articles where it was stated that eventually the Sun would reach a stage where it would expand to a size larger than Earth's orbit, then after a while it would shrink down to dwarf size.

 

Now these calculations involved an estimate of time, but it is unclear to me whether they are talking Sun time, or Earth time.

[Syd]

In some 5 bln years sun will be a red giant and eat earth 4 breakfast.

But sun won't 'be' a supernova, couse it's weight its too little.

[mmalluck]

GR doesn't play the role you think it does. Time dialation is dependant on your reference frame. If your sitting on the sun, earth-time appears to be moving slower. If your sitting on the earth, sun-time appears to be going slower. On which body is time traveling more slowly? Niether.

 

The sun is about 8 light-seconds away from earth, so anything that happens to the sun will be not be observable to use for a full 8 seconds. As the sun expands to become a red giant, the surface of the sun will be moving closer to us, so this lag will shrink, until the sun eats us.

[swansont]

GR doesn't play the role you think it does. Time dialation is dependant on your reference frame. If your sitting on the sun' date=' earth-time appears to be moving slower. If your sitting on the earth, sun-time appears to be going slower. On which body is time traveling more slowly? Niether.

 

The sun is about 8 light-seconds away from earth, so anything that happens to the sun will be not be observable to use for a full 8 seconds. As the sun expands to become a red giant, the surface of the sun will be moving closer to us, so this lag will shrink, until the sun eats us.[/quote']

 

I don't think gravitational time dilation is symmetric the way it is in SR. You can tell if you're in an accelerating reference frame. A clock near the sun will tick slower as it is deeper in a gravity well as compared to a clock on the earth. Just as clocks on the earth tick at different rates depending on altitude. Observers in both locations can agree on that.

[insane_alien]

GR doesn't play the role you think it does. Time dialation is dependant on your reference frame. If your sitting on the sun' date=' earth-time appears to be moving slower. If your sitting on the earth, sun-time appears to be going slower. On which body is time traveling more slowly? Niether.

 

The sun is about 8 light-seconds away from earth, so anything that happens to the sun will be not be observable to use for a full 8 seconds. As the sun expands to become a red giant, the surface of the sun will be moving closer to us, so this lag will shrink, until the sun eats us.[/quote']

 

umm the sun is eight light MINUTES away not seconds if we were eight light seconds from the sun everybody would have hellish sunburn and water would be a vapour

[mmalluck]

my bad. I knew it was 8 something or another.

[Janus]

 

Now these calculations involved an estimate of time' date=' but it is unclear to me whether they are talking Sun time, or Earth time.[/quote']

 

It doesn't really matter. Over a period of, say, four biilion years, Earth time and Sun time would differ by less than 8000 yrs. This is this is much smaller than any reasonable margin of error in that estimate.

[Ophiolite]

And in around 1.5 billion years the slowly increasing solar temperature moves the Goldiocks zone beyond the Earth's atmosphere. So the red giant phase is truly academic for any Earth life: it is long defunct (or has emigrated).