# Before the Sun Becomes a Nova **URL:** \ **Category:** Factual Questions\ **Created:** [May 20, 2013, 8:59pm UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867 "2013-05-20T20:59:18Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Goosie](https://avatars.discourse-cdn.com/v4/letter/g/b5a626/32.png) [@Goosie](https://boards.straightdope.com/u/Goosie)\ **Post date:** [May 20, 2013, 8:59pm UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/1 "2013-05-20T20:59:18Z")
Before our Sun becomes a nova, would there be any kind of warning beforehand, or would it happen with no warning signs at all? ---
**Author:** ![Skald\_the\_Rhymer](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)\ **Post date:** [May 20, 2013, 9:06pm UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/2 "2013-05-20T21:06:32Z")
> [@Goosie](#): > > Before our Sun becomes a nova, would there be any kind of warning beforehand, or would it happen with no warning signs at all? [Sol is not the sort of star that goes nova.](http://en.wikipedia.org/wiki/Nova#Etymology) [It is also not nearly large enough to go supernova.](http://en.wikipedia.org/wiki/Supernova) ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [May 20, 2013, 9:09pm UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/3 "2013-05-20T21:09:09Z")
So, walking outside one morning and seeing that the sun has turned into a red giant, filling half the sky? That’d be one sign. ---
**Author:** ![Full\_Metal\_Lotus](https://avatars.discourse-cdn.com/v4/letter/f/df705f/32.png) [@Full\_Metal\_Lotus](https://boards.straightdope.com/u/Full_Metal_Lotus)\ **Post date:** [May 20, 2013, 9:30pm UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/4 "2013-05-20T21:30:47Z")
Sol will eventually wind up as a Red Giant, but it won’t happen over night - as I understand it, Helium is the “Ash” of the Hydrogen + Hydrogen fusion process currently powering our sun. As the helium ash accumulates, it begins to lower the temp at the core, resulting in a change in which the star operates, turning it into a red giant. No doubt a better informed expert will be along to clarify and correct what I have said, but one thing I do know is that it is a gradual process taking many millions of years to happen. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [May 20, 2013, 9:41pm UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/5 "2013-05-20T21:41:41Z")
No the temperature of the core rises as the helium “burning” (i.e. fusion) starts. This results in the expansion of the star and a lowering of its surface temperature that determines its color. But it is larger and radiates more energy. The sun is slowly expanding as we speak and, in a mere billion or so years, the earth is likely to become too hot for us. In five billion years, it will have expanded to about the size of the earth’s orbit and will be a full-blown red giant. But unless we have colonized distant stars, we won’t be around to witness this. I wonder what Mars will be like. It is only long after that stage has passed that it would be possible for the sun to undergo novas. ---
**Author:** ![digs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/digs/32/14889_2.png) [@digs](https://boards.straightdope.com/u/digs)\ **Post date:** [May 21, 2013, 2:32am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/6 "2013-05-21T02:32:39Z")
I half expected to see \*\*“Need Answer Fast” \*\*under the thread title. ---
**Author:** ![Washoe](https://avatars.discourse-cdn.com/v4/letter/w/ecae2f/32.png) [@Washoe](https://boards.straightdope.com/u/Washoe)\ **Post date:** [May 21, 2013, 3:05am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/7 "2013-05-21T03:05:52Z")
> [@digs](#): > > I half expected to see \*\*“Need Answer Fast” \*\*under the thread title. Ooh—what is the name of that short story that later became an episode of The (new) Outer Limits? ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [May 21, 2013, 3:21am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/8 "2013-05-21T03:21:39Z")
> [@Washoe](#): > > Ooh—what is the name of that short story that later became an episode of The (new) Outer Limits? [Inconstant Moon](http://en.wikipedia.org/wiki/Inconstant_Moon_%28The_Outer_Limits%29). Adapted from his short story of the same name by Larry Niven. [Wiki](http://en.wikipedia.org/wiki/Inconstant_Moon) about the short story. ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [May 21, 2013, 3:31am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/9 "2013-05-21T03:31:54Z")
Relax, the surface of the Earth will be burnt into a cinder way before Sol becomes a red giant. ---
**Author:** ![Washoe](https://avatars.discourse-cdn.com/v4/letter/w/ecae2f/32.png) [@Washoe](https://boards.straightdope.com/u/Washoe)\ **Post date:** [May 21, 2013, 3:36am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/10 "2013-05-21T03:36:18Z")
> [@runner pat](#): > > [Inconstant Moon](http://en.wikipedia.org/wiki/Inconstant_Moon_%28The_Outer_Limits%29). Adapted from his short story of the same name by Larry Niven. Yeah, that’s it—great episode. ---
**Author:** ![Bremidon](https://avatars.discourse-cdn.com/v4/letter/b/ac91a4/32.png) [@Bremidon](https://boards.straightdope.com/u/Bremidon)\ **Post date:** [May 21, 2013, 10:23am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/11 "2013-05-21T10:23:05Z")
> [@Ranger\_Jeff](#): > > Relax, the surface of the Earth will be burnt into a cinder way before Sol becomes a red giant. Probably. I’ve been hearing predictions recently giving the Earth a maximum of 1 billion years before getting too hot to sustain life on the surface. For some reason, that’s kind of disturbing, considering that the sun has around 4 billion years left before starting to slowly puff up to a red giant stage. ---
**Author:** ![Satchmo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/satchmo/32/4223_2.png) [@Satchmo](https://boards.straightdope.com/u/Satchmo)\ **Post date:** [May 21, 2013, 10:19pm UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/12 "2013-05-21T22:19:02Z")
> [@Bremidon](#): > > Probably. I’ve been hearing predictions recently giving the Earth a maximum of 1 billion years before getting too hot to sustain life on the surface. > > For some reason, that’s kind of disturbing, considering that the sun has around 4 billion years left before starting to slowly puff up to a red giant stage. Well, you see, if you put a frog on a planet and then slooooowly turn up the heat… 😃 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 22, 2013, 2:04am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/13 "2013-05-22T02:04:23Z")
> [@](#): > > Yeah, that’s it—great episode. I’ve never seen the episode, but I think it’s the best science fiction short story yet written. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [May 22, 2013, 4:55am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/14 "2013-05-22T04:55:47Z")
We’ve got a billion years. Use the moon as a gravitational tug boat, and dock Earth into safe harbor over millions of years. Kid’s stuff. ---
**Author:** ![Washoe](https://avatars.discourse-cdn.com/v4/letter/w/ecae2f/32.png) [@Washoe](https://boards.straightdope.com/u/Washoe)\ **Post date:** [May 22, 2013, 5:47am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/15 "2013-05-22T05:47:15Z")
> [@Chronos](#): > > I’ve never seen the episode, but I think it’s the best science fiction short story yet written. Yeah, I’ll bet the short story was even better than the TOL episode. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [May 22, 2013, 6:07am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/16 "2013-05-22T06:07:58Z")
The phenomenon described in \*Inconstant Moon/I] is a ‘superflare’, a phenomenon which has been observed in other sun-like stars but which does not seem to have ever happened in our system. > **[Superflare](https://en.wikipedia.org/wiki/Superflare)** > > Superflares are very strong explosions observed on stars with energies up to ten thousand times that of typical solar flares. The stars in this class satisfy conditions which should make them solar analogues, and would be expected to be stable over very long time scales. > The original nine candidates were detected by a variety of methods. No systematic study was possible until the launch of the Kepler space telescope, which monitored a very large number of solar-type stars with very high accuracy ... ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [May 22, 2013, 6:09am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/17 "2013-05-22T06:09:34Z")
> [@eburacum45](#): > > The phenomenon described in \*Inconstant Moon/I] is a ‘superflare’, a phenomenon which has been observed in other sun-like stars but which does not seem to have ever happened in our system. > [Superflare - Wikipedia](http://en.wikipedia.org/wiki/Superflare) _Yet._ ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [May 22, 2013, 6:45am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/18 "2013-05-22T06:45:05Z")
Well, we’ve had about 500 million years of complex life on Earth without a superflare that has left any detectable trace on Earth; now I come to think of it that doesn’t mean very much. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [May 22, 2013, 6:59am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/19 "2013-05-22T06:59:23Z")
It just means we’re overdue! Just, find a deep, deep cave and hunker down come February 13th, 2024. Do not ask me how I know this. But yeh, I have a time machine. ---
**Author:** ![Washoe](https://avatars.discourse-cdn.com/v4/letter/w/ecae2f/32.png) [@Washoe](https://boards.straightdope.com/u/Washoe)\ **Post date:** [May 22, 2013, 7:06am UTC](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867/20 "2013-05-22T07:06:46Z")
Personally, I’d be more worried about a gamma ray burst. [Next page](https://boards.straightdope.com/t/before-the-sun-becomes-a-nova/658867.md?page=2)