# Can a star still explode without aging? **URL:** \ **Category:** Factual Questions\ **Created:** [August 2, 2005, 9:30pm UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358 "2005-08-02T21:30:44Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![ParentalAdvisory](https://avatars.discourse-cdn.com/v4/letter/p/53a042/32.png) [@ParentalAdvisory](https://boards.straightdope.com/u/ParentalAdvisory)\ **Post date:** [August 2, 2005, 9:30pm UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/1 "2005-08-02T21:30:44Z")
You hear about the supernovas, but do stars necessarily have to age for them to explode? For example, could our Sun suddenly _lose_ it? :eek: ---
**Author:** ![Thin\_Lizzy](https://avatars.discourse-cdn.com/v4/letter/t/e9a140/32.png) [@Thin\_Lizzy](https://boards.straightdope.com/u/Thin_Lizzy)\ **Post date:** [August 2, 2005, 9:33pm UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/2 "2005-08-02T21:33:46Z")
> [@ParentalAdvisory](#): > > could our Sun suddenly _lose_ it? :eek: Oh great. Now I have something else to worry about :smack: 😃 ---
**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:** [August 2, 2005, 10:18pm UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/3 "2005-08-02T22:18:58Z")
There is no evidence to support that it would. Whenever we see a supernova, astronomers always dig up old images of that part of the sky to try to find the progenitor star, before it exploded. When they do, it’s always an old one. And there’s no known theoretical mechanism by which a young or middle-aged star could suddenly go nova. So no, **Thin Lizzy** doesn’t have something else to worry about. ---
**Author:** ![TimeWinder](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@TimeWinder](https://boards.straightdope.com/u/TimeWinder)\ **Post date:** [August 2, 2005, 10:33pm UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/4 "2005-08-02T22:33:07Z")
Also, our sun is too small to become a supernova. So all you’d have to worry about is expansion into a red giant consuming the Earth. Hardly worth mentioning, really. ---
**Author:** ![The\_Controvert](https://avatars.discourse-cdn.com/v4/letter/t/dec6dc/32.png) [@The\_Controvert](https://boards.straightdope.com/u/The_Controvert)\ **Post date:** [August 2, 2005, 11:21pm UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/5 "2005-08-02T23:21:14Z")
So how long does it take between the time it start expanding and the time it engulfs the Earth? ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [August 2, 2005, 11:59pm UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/6 "2005-08-02T23:59:39Z")
Doesn’t a star only go supernova once all the hydrogen and helium have been fused? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [August 3, 2005, 12:04am UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/7 "2005-08-03T00:04:31Z")
> [@TimeWinder](#): > > Also, our sun is too small to become a supernova. So all you’d have to worry about is expansion into a red giant consuming the Earth. Hardly worth mentioning, really. Our sun won’t go nova but what about the helium flash? I know this is supposed to be a sort of explosion but I have no clue how powerful it is (it will not destroy the core I know but would it affect the earth?). ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [August 3, 2005, 12:22am UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/8 "2005-08-03T00:22:26Z")
> [@Shalmanese](#): > > Doesn’t a star only go supernova once all the hydrogen and helium have been fused? After helium fuses into carbon I think our sun is done. I do not think it can manage to fuse carbon. A planetary nebula will form as the sun’s outer layers drift away leaving a white dwarf. The white dwarf glows from heat but is not activley fusing anything. Eventually it will cool off and be a black dwarf…essentially a cold lump of carbon floating about. A larger star can fuse all the way up to iron but iron is a net energy loser in fusion. It is here you get the supernova. The core will continue to collapse as no fusion in the iron initiates to make a repulsive force. Eventually the repulsive forces of the atoms is more than the gravitational contraction. **BOOM** ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [August 3, 2005, 1:36am UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/9 "2005-08-03T01:36:08Z")
There is an exception to the aging star running out of fuel scenario but it doesn’t have any application to our sun: > **[Supernova](https://en.wikipedia.org/wiki/Supernova)** > > A supernova (/ˌsuːpərˈnoʊvə/ plural: supernovae /ˌsuːpərˈnoʊviː/ or supernovas, abbreviations: SN and SNe) is a powerful and luminous stellar explosion. This transient astronomical event occurs during the last evolutionary stages of a massive star or when a white dwarf is triggered into runaway nuclear fusion. The original object, called the progenitor, either collapses to a neutron star or black hole, or is completely destroyed. The peak optical luminosity of a supernova can be comparable to tha... > [@](#): > > There are two possible routes to this end: either a massive star may cease to generate fusion energy in its core and collapse inward under the force of its own gravity, or a white dwarf star may accumulate material from a companion star until it reaches a critical mass and undergoes a thermonuclear explosion. The part below about Type 1a supernovae goes into more detail about accretions. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [August 3, 2005, 1:44am UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/10 "2005-08-03T01:44:23Z")
For those interested a really good book on the sun is George Gamow’s _The Birth and Death of The Sun._ Gamow was a top-notch scientist (for example, the Big Bang theory) and an interesting and entertaining writer. ---
**Author:** ![TimeWinder](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@TimeWinder](https://boards.straightdope.com/u/TimeWinder)\ **Post date:** [August 3, 2005, 3:14am UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/11 "2005-08-03T03:14:59Z")
> [@Whack-a-Mole](#): > > Our sun won’t go nova but what about the helium flash? I know this is supposed to be a sort of explosion but I have no clue how powerful it is (it will not destroy the core I know but would it affect the earth?). OK, maybe the Earth being engulfed wouldn’t be ALL you’d have to worry about. The world supply of ice cream would probably melt, too. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [August 3, 2005, 9:52am UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/12 "2005-08-03T09:52:33Z")
> [@TimeWinder](#): > > Also, our sun is too small to become a supernova. So all you’d have to worry about is expansion into a red giant consuming the Earth. Hardly worth mentioning, really. According to my astronomy teacher, the Sun’s output is steadily increasing as it ages. This will eventually result in “thermal runaway” on the Earth, when it is no longer able to handle the increased energy input from the Sun, turning it into a Venus-like inferno. The end may be nearer than you think. ---
**Author:** ![mazinger\_z](https://avatars.discourse-cdn.com/v4/letter/m/5f9b8f/32.png) [@mazinger\_z](https://boards.straightdope.com/u/mazinger_z)\ **Post date:** [August 3, 2005, 4:11pm UTC](https://boards.straightdope.com/t/can-a-star-still-explode-without-aging/315358/13 "2005-08-03T16:11:30Z")
> [@The Controvert](#): > > So how long does it take between the time it start expanding and the time it engulfs the Earth? I’m far too busy (and, let’s not forget lazy) to dig up a cite, but I remember from a film in my AP Physics class that said that by the time the Sun expands to a red giant, all life on Earth will have died. It was quite the cool looking computer graphics (like CGI, but 90’s style). Anyway, they estimated 5 billion years (sorry, no cite) for the Sun to go red giant. I believe it was the same film that said that Earth will have cooled off by then. My memory fails me as to why the Earth would no longer be habitable.