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ObiWan377
2003-May-21, 07:40 PM
I was talking to my friend today and he told me he read in a newpaper that the Sun would explode in 3 years. When I got home, I did research on it and found that it was a Weekly World News Article. But it got me curious. When will the Sun explode, and would there be any signs of it? Sorry, if this is a dumb question( I have a record of them) but i'm just curious. I know jack about astronomy (but i'm thinking about learning), and would like to know this.

Glom
2003-May-21, 07:50 PM
Is this the next generation of doomsayers? First it was the Great Alignment, then it was Planet X, now this.

Kizarvexis
2003-May-21, 08:01 PM
As I understand it, in 5 million years or so, the sun will expand into a red giant. It will have a diameter of around Venus' to Earth's orbit. Either way, it is bad for life on earth. After a few million more years, the sun will contract into a white dwarf star.

Kizarvexis
Who reserves the right to have mis-remembered this stuff from school many years ago. :)

nexus
2003-May-21, 08:16 PM
I believe it's five billion years 8)

MAPNUT
2003-May-21, 08:20 PM
This is exactly how a famous joke started, which I heard many years ago. After five million is corrected to five billion, the punch line is, "Whew! You had me scared!"

calliarcale
2003-May-21, 08:30 PM
Assuming our modern astrophysics is correct, then there would be plenty of warning signs thousands or even millions of years in advance. For instance, the sun swelling to supergiant size would probably be a bit of a giveaway. ;) It will do that before it goes nova, shedding its outer layers and collapsing down to a white dwarf.

Note: the Sun will someday go nova, but it will not go supernova. It is not sufficiently massive, and is not going to get beyond the helium-fusion stage. Right now, it is at the hydrogen-fusion stage. This will last quite a long time, and there is a very real possibility that our species will be either extinct or long migrated to other worlds, so I wouldn't worry about it too much. :)

dgruss23
2003-May-21, 08:34 PM
The Sun is currently on the Main Sequence which means its fusing hydrogen into helium in its core. This has been going on for about 4.5-4.6 billion years according to current age estimates. From the models it is expected that the Sun has a Main Sequence life of about 10 Billion years which gives it another ~5.5 billion years before it begins entering the Red Giant phase.

As a sidelight, life on Earth may only have about 0.5 to 1.5 billion years left because stars have steadily increasing luminosities on the Main sequence. At some point before the Red Giant phase the Sun should get too hot for the existence of water on the surface.

Edited to add - "too hot for the existence of water on the surface" of the Earth.

ObiWan377
2003-May-21, 08:41 PM
Ok, I see now. I can now laugh in my friends face and prove him wrong.

Edit: Forgot to say thanks. Thanks everyone.

BCstargazerr
2003-May-22, 12:47 AM
The Sun is currently on the Main Sequence which means its fusing hydrogen into helium in its core. This has been going on for about 4.5-4.6 billion years according to current age estimates. From the models it is expected that the Sun has a Main Sequence life of about 10 Billion years which gives it another ~5.5 billion years before it begins entering the Red Giant phase.

All of this is text book accuracy at its best. but the little annoying voice in my head tells me that actually all of this is a "good guess" we haven't seen actual "transitions" from one stage to another. i could elaborate ad nauseam.
all of this to get to my point. we've been taking for granted the constant output of our nearest star. we don't understand yet what happened a few centuries ago when its activity decreased substancially for months.

text books are fine but discourage the mere thought of questionning the methods employed to calculate the different variable of the sun.
I still think that i have a better chance of winning the big lotto than the sun to "explode" in 3 years.
as nancy written a book about that yet...how Px will hit the sun and so on...what her solid date for that event ?

So Many Wonders In The Sky To Observe, So Little Time

dgruss23
2003-May-22, 01:11 AM
The Sun is currently on the Main Sequence which means its fusing hydrogen into helium in its core. This has been going on for about 4.5-4.6 billion years according to current age estimates. From the models it is expected that the Sun has a Main Sequence life of about 10 Billion years which gives it another ~5.5 billion years before it begins entering the Red Giant phase.

All of this is text book accuracy at its best. but the little annoying voice in my head tells me that actually all of this is a "good guess" we haven't seen actual "transitions" from one stage to another. i could elaborate ad nauseam.

Its more than a guess. You've seen the Hertsprung-Russell diagram and H-R diagrams for clusters. The H-R diagram provides a map of the stellar life cycle. Astronomers can observe stars at all these different stages and test their models against those observations. As for transitions, here (http://antwrp.gsfc.nasa.gov/apod/ap010805.html) is a planetary nebula that is newly forming.


all of this to get to my point. we've been taking for granted the constant output of our nearest star. we don't understand yet what happened a few centuries ago when its activity decreased substancially for months.

I agree 100% with you on this. I made that point on this (http://www.badastronomy.com/phpBB/viewtopic.php?p=74158#74158) thread.


text books are fine but discourage the mere thought of questionning the methods employed to calculate the different variable of the sun.

Textbooks are a beginning, not an end. But you have to know what is known before you can discover that which is not known. Its one of the problems with all this educational "theory" about teaching "problem solving" skills. If you emphasize problem-solving before the students have any knowledge to solve problems with, then what are you accomplishing? So you start with textbook knowledge - simplified though it be.

russ_watters
2003-May-22, 01:53 AM
Textbooks are a beginning, not an end. But you have to know what is known before you can discover that which is not known. Its one of the problems with all this educational "theory" about teaching "problem solving" skills. If you emphasize problem-solving before the students have any knowledge to solve problems with, then what are you accomplishing? So you start with textbook knowledge - simplified though it be. Put another way, you can't reasonably question a theory until you have learned what the theory is and how it works. So the knowledge comes first. The extension to unstructured problem solving and critical thinking comes second.

BlAcKNoVa
2003-May-22, 05:55 AM
Note: the Sun will someday go nova, but it will not go supernova. It is not sufficiently massive, and is not going to get beyond the helium-fusion stage. Right now, it is at the hydrogen-fusion stage. This will last quite a long time, and there is a very real possibility that our species will be either extinct or long migrated to other worlds, so I wouldn't worry about it too much.

Umm, how will the sun go nova? As I understand, the sun will never go nova. :)

Iain Lambert
2003-May-22, 07:58 AM
He was almost right, actually. The Sun will explode tomorrow, when it reports the latest asylum figures. But then it does that every time they are released.

Oh, you didn't mean Mr. Murdoch's paper, did you? ;)

MAPNUT
2003-May-22, 01:51 PM
As a sidelight, life on Earth may only have about 0.5 to 1.5 billion years left because stars have steadily increasing luminosities on the Main sequence. At some point before the Red Giant phase the Sun should get too hot for the existence of water on the surface.


Whew! So we have 500 million years, not 5 million years. But not 5 billion. We better start planning.

dgruss23
2003-May-22, 02:24 PM
As a sidelight, life on Earth may only have about 0.5 to 1.5 billion years left because stars have steadily increasing luminosities on the Main sequence. At some point before the Red Giant phase the Sun should get too hot for the existence of water on the surface.


Whew! So we have 500 million years, not 5 million years. But not 5 billion. We better start planning.

I've decided not to buy that beachfront property! But I'm investing in sunblock. :D

tracer
2003-May-22, 03:43 PM
I was talking to my friend today and he told me he read in a newpaper that the Sun would explode in 3 years. When I got home, I did research on it and found that it was a Weekly World News Article.
Was there also an article in The Sun predicting that the Weekly World News would explode in 3 years? ;)

tracer
2003-May-22, 03:48 PM
Umm, how will the sun go nova? As I understand, the sun will never go nova.
No kidding. It's kinda hard for anything to go nova without a close-orbiting white dwarf companion.



He was almost right, actually. The Sun will explode tomorrow, when it reports the latest asylum figures. But then it does that every time they are released.

Oh, you didn't mean Mr. Murdoch's paper, did you? ;)
D'OH! Somebody already beat me to the punch. Darn you to heck!

Spaceman Spiff
2003-May-22, 05:30 PM
we've been taking for granted the constant output of our nearest star. we don't understand yet what happened a few centuries ago when its activity decreased substancially for months.

The peak to trough change in the Sun's luminosity over a full sunspot cycle is about 0.1% (highest during peak sunspot activity). The Maunder minium was a time period 1645-1715 over which very few sunspots were "spotted" by observers - the Sun was effectively stuck in a "sunspot minimum". I don't recall the estimated depression in the solar luminosity over that or subsequent time period (the so-called "Little Ice Age"), but I am fairly certain that it wasn't much more than this 0.1% value. These changes in luminosity are short time scale ones associated with the Sun's magnetic cycle -- not nuclear fusion or thermal time scales that are MUCH longer. We are talking about "weather" on the Sun, here. This "weather" is important to understand, but not in the big picture as to how well we understand the fundamentals of stars and their evolution.

And no, the Sun is NOT expected to "go nova". Novae always occur in close binary systems in which one of the members is a white dwarf, accreting mass from its partner. Instead, our Sun's envelope will gently "blow away" in several wind episodes to become a planetary nebula, like this (http://antwrp.gsfc.nasa.gov/apod/ap030510.html), its carbon/oxygen core contracting to become a white dwarf (the dim object at the center of the image).

russ_watters
2003-May-23, 03:44 PM
Umm, how will the sun go nova? As I understand, the sun will never go nova.
No kidding. It's kinda hard for anything to go nova without a close-orbiting white dwarf companion. Huh? What does a companion have to do with the evolution of an individual star? The sun is a slightly below average mass star and slightly below average mass stars burn for about 10 billion years and end with a nova.

Blacknova, you're not confusing "nova" with "supernova" are you?

ToSeek
2003-May-23, 03:53 PM
Umm, how will the sun go nova? As I understand, the sun will never go nova.
No kidding. It's kinda hard for anything to go nova without a close-orbiting white dwarf companion. Huh? What does a companion have to do with the evolution of an individual star? The sun is a slightly below average mass star and slightly below average mass stars burn for about 10 billion years and end with a nova.

Blacknova, you're not confusing "nova" with "supernova" are you?

I believe he's thinking of a type Ia supernova, which is believed to be caused by gas accreting from a partner star.

Spaceman Spiff
2003-May-23, 04:48 PM
Umm, how will the sun go nova? As I understand, the sun will never go nova.
No kidding. It's kinda hard for anything to go nova without a close-orbiting white dwarf companion. Huh? What does a companion have to do with the evolution of an individual star? The sun is a slightly below average mass star and slightly below average mass stars burn for about 10 billion years and end with a nova.

Blacknova, you're not confusing "nova" with "supernova" are you?

It has everything to do with it. Evolution in close binary systems can be a lot differen than for lonely stars. e.g., star's like Algol, cataclysmic binary systems, AND those that produce novae, all have evolutionary characteristics that are directly attributable to the fact that two stars are in a close (interacting) binary system. And NO, the Sun will not "go nova", by any astronomer's definition of such.

mvela
2003-May-23, 04:53 PM
Yeah, and there is .....a new plan to "blow the moon to smithereens"... :lol:

http://www.snopes.com/science/sunboom.htm

I see a new doomsday cult coming...... :x

OscartheGrouch
2003-May-23, 06:51 PM
Of course the sun will explode in 3 years or less because, like every other place in this neighborhood, there is an illegal meth lab inside.

A few months ago I actually bought an issue of WWN because the cover story was that a Japanese midget submarine (the "missing" one from the Pearl Harbor attack, no less) was still on the loose after 60 years and was probably responsible for dozens of unexplained sinkings in the Pacific during that time. "And--it's heading for the California coast!!!!" I posted it on the History Channel BBS, World War II forum, with appropriate MST3K-type commentary, and got some laughs, the biggest from a published author of naval history. Other responses were aghast that I had missed the WWN story about the B-29 stranded on the moon. It should stay remarkably well-preserved up there.

Whoa, what's this about only 5*10^8 years left to live on earth? I thunk we had longer than that. If the sun is more luminous, can't we just evolve or genetically engineer some inner eyelids like the Vulcans? Or is it the additional radiation thing?

BCstargazerr
2003-May-23, 09:02 PM
I hope the "world news" will do a story about flight 19's marooning on Mimas when the Cassini probe gets to Saturn next year.
Obviously the great conspirators of this world have made sure no pics will be taken and sabotaged the probe with the HAARP array
and what will happen when Px collides with the sun and emerges on the other side ??
all them questions and so few answers :D

Odinoneeye
2003-May-24, 05:32 AM
There was a recent article on Space.com that talked about this issue. It postulated that when the swelling of the sun begins, we can live on Pluto or a moon of Neptune.

BlAcKNoVa
2003-May-24, 08:00 AM
I'm pretty sure by the time we got to get off planet Earth, the human race would be a lot farther out than Pluto or one of Neptune's moons.

informant
2003-May-24, 11:11 AM
As a sidelight, life on Earth may only have about 0.5 to 1.5 billion years left because stars have steadily increasing luminosities on the Main sequence. At some point before the Red Giant phase the Sun should get too hot for the existence of water on the surface.

Maybe then we can move to Mars... (or Titan?)

Darnon
2003-May-24, 06:15 PM
One of the other running theories is that the sun, while it will expand, it will not gain any amount in mass and thus decrease its density as its volume increased. Thus, the gravitational force exerted would be lesser and the planets would sort of spread out to wider orbit. Of course, this is if it hasn't been disproven and taken with the fact that I don't much about physics....

Darnon

daver
2003-May-24, 06:39 PM
One of the other running theories is that the sun, while it will expand, it will not gain any amount in mass and thus decrease its density as its volume increased. Thus, the gravitational force exerted would be lesser and the planets would sort of spread out to wider orbit. Of course, this is if it hasn't been disproven and taken with the fact that I don't much about physics....

Darnon

Gravitational force is a function of mass, not density. If the sun expanded to the size of Venus' orbit, the effect on the orbit of earth would be insignificant.

However, the sun could lose mass in the process of expanding to that size (i'll let someone who isn't as apt to stick their foot in their mouth explain the process). This loss of mass, not the decrease in density, is what could cause the change in orbits.

Darnon
2003-May-24, 07:41 PM
That's kind of what I figured, but with lack of any better knowing, figured I'd just post it and see what was said about it.
Don't believe everything the BBC tells you, I guess...

Darnon

tracer
2003-May-25, 05:26 AM
It's kinda hard for anything to go nova without a close-orbiting white dwarf companion. Huh? What does a companion have to do with the evolution of an individual star? The sun is a slightly below average mass star and slightly below average mass stars burn for about 10 billion years and end with a nova.
Hoo boy.

Okay, repeat after me:
A "Red Giant" is not at all the same thing as a "Nova."
A "Red Giant" is not at all the same thing as a "Nova."
A "Red Giant" is not at all the same thing as a "Nova."

Red Giant = the bloated phase a star enters after its main-sequence lifetime. Depending on the mass of the star, the red giant phase can last for millions of years. Furthermore, it usually takes tens of thousands of years for a star entering the red giant phase to expand from its main-sequence diameter to its red giant diameter.

Nova = a sudden outburst from a white dwarf in a mass-exchange binary, where the white dwarf has accreted enough material from its companion for the pressure and temperature of the accreted material to reach the nuclear fusion point. (Not to be confused with a type 1a supernova, in which a white dwarf in a mass-exchange binary accretes enough material to exceed the 1.4 solar mass Chandrasekhar limit.)


The sun will not go nova. It cannot go nova. It does not have a white dwarf companion to dump material onto. And even when the sun becomes a white dwarf itself, the white dwarf former-sun will not have a companion to suck material from.

The sun will, however, become a red giant.

ToSeek
2003-May-25, 01:54 PM
As a sidelight, life on Earth may only have about 0.5 to 1.5 billion years left because stars have steadily increasing luminosities on the Main sequence. At some point before the Red Giant phase the Sun should get too hot for the existence of water on the surface.

Maybe then we can move to Mars... (or Titan?)

Or Pluto (http://www.space.com/scienceastronomy/pluto_habitable_030520.html)