Is the statement that the Sun will live for a few billion or a few trillion years just a theory?

Question

I heard that it was just a theory. So if its just a theory, is it possible that it could live for almost forever?

This is the definition of "theory" as I know it. It is a statement with some hard evidence, but it isn't PROVEN. That is why it is different from fact.

Answer 1

It's a theory, as is almost anything we attempt to predict in the future. But it is a solid theory. This does not mean it can be altered to suit one's beliefs or wishes. The predicted age of 4 to 5 billion more years is reliable, based on the large amount of information we have about the sun and about stellar evolution, in general. If one wishes to dispute this prediction, it is necessary to show why it is wrong and the new theory is better.

BTW, after it goes through its red giant phase, there will be a white dwarf left at the center. This small stellar remnant will probably persist for many times longer than the sun did. In fact, it is believed that these white dwarfs can last essentially for the lifetime of the Universe, whatever that is.

Answer 2

1) Theory: in science the word has a very strict meaning. It is a set of hypotheses and equations that leads to predictions that can be (and have been) verified.
So, if it is a (scientific) theory, probability is high that it will happen that way.

2) The theory is based on the assumption that the sun's energy comes from the fusion of hydrogen into helium at the core of the sun, where the temperature would be around 15 million degrees C and the pressure sufficient to smash protons together (hydrogen nuclei) to form helium nuclei. These conditions are needed according to fusion theory in nuclear physics.

4 hydrogen nuclei together weigh a bit more than one helium atom. It is the difference in mass that is transformed in energy (E = mc^2, according to another well known theory). Four million tonnes per second of mass become energy.

We also know that the Sun has a finite size. Therefore, there will be a time that the Sun's core will become saturated with helium atoms and fusion will no longer proceed (the Sun's core is not hot nor pressurised enough for helium fusion). When the Sun runs out of core fuel, it will have to evolve. One way is to become a red giant.

According to our best knowledge (theory), and based on observations of other stars in the universe (verification of theory by observation), this shoud happen in approximately 5 billion years.

Of course, since this is all based on theory, you are free to start your own theory. However, if you want your theory to be taken seriously, you will have to show how your theory is better at explaining what we see in the universe.

At first, there were many theories to explain how the sun works. They ranged from the big -- and I mean, really big -- lump of coal burning (without smoke?) to the gravitational energy released by a slowly contracting ball of gas.

Each one in turn had to be set aside because it failed to explain what was observed on the Sun and/or other stars.

The present 'theory' survives because it has, so far, explained everything we see (even though we did have problems with the number of neutrinos detected in underground neutrino observatories -- we eventually had to change our understanding of neutrinos and accept that neutrinos really had some mass).

Answer 3

Given the enormous size of the Sun, which is not big in comparison to some other stars, and the fact that it is consuming its primary fuel source (Hydrogen Gas) at a more or less fixed rate with no new supplies of Hydrogen Gas available anywhere nearby, it only makes sense that one could predict an end to the supply of Hydrogen on the Sun.

Theories or calculations I have read suggest that the supplies of Hydrogen on the Sun will run out in about 5 Billion Years. I do not think that the calculations are precise enough to name any "specific year" way out there in the future. As far as working with (mentally) the idea of 5 Billion Years, when you consider the lifespan of a human being to be 100 years, that is a pretty long time, and the end will not be seen by you or I, our children, or their children's children... So it is a pretty long time in the future.

Yes I believe it. Can we do anything about it? Nope.

Answer 4

First of all, stop saying "just a theory" when what you actually mean is "just a hypothesis". In science, a theory is a very highly respected thing, with evidence backing it up.
To answer your question, scientists are very certain that the Sun has about five billion years to go before it enters its red giant phase. The Sun is a main sequence star, and those behave very predictably.

Answer 5

It *is* a theory; your problem is misuunderstanding the word "theory" in a scientific context. A theory is a prediction based on physical evidence and physics models of the behaviour of systems, and implies a great deal of confidence in those predictions. According to current theory, the sun will burn for roughly five billion more years, then it will swell into a red giant (possibly vapourizing Earth in the process) and then may explode in a planetary nova or simply cool down to a dwarf star.

In less formal, non-scientific language "theory" is used in a much looser context. The scientific word that corresponds to this looser meaning is "hypothesis".

Answer 6

No it is not just a theory.
The Sun has a finite size.
The Sun fusions a set amount of hydrogen into helium every second.
Therefore the Sun can only exist in its present state for its ;
Mass ÷ Rate of fusion= seconds of 'life'

Since the starting mass of hydrogen is very large indeed then the expected life of the Sun is around 10 billion years .As of yesterday, the Sun has used up 5 billion years worth of hydrogen.
In another 5 billion years it will switch over to fusioning helium.
This will cause the Sun to massively increase in size until it engulfs all the planets inside Jupiter's orbit.
Earth will become a "crispy critter".

Answer 7

Well its a theory, but saying its ''just'' a theory is like saying evolution is ''just'' a theory. There is an amazing amount of proof for the theory, based on observable, undeniable, facts, that can be recreated upon demand. Also, there are thousands of people devoting their lives to try to prove these theories wrong, and they haven't been able to.
As far as we're concerned though, a few billion years might as well be forever.

Answer 8

Every time I hear that phrase "just a theory", I just cringe at the *TERRIBLE* state of science education in my country (the U.S. ... and yes, it is always fellow Americans using this phrase). We have kids memorizing the Krebs' cycle, or reciting parts of the periodic table ... and yet these kids have no concept of the *basics* of science ... like what the word 'theory' means.

There's no 'just' in theory. A theory in science means a pretty well established explanation for a set of facts ... well established by a bank of reproducible evidence. In this case, the theory of how stars develop and die is extremely well established. We can compute the average life span of a star the size of our sun (10 billion years), determine how far along our sun is in that life span (about 5 billion years), and compute how much is left (about another 5 billion years).

Please, please, please, don't ever say "just a theory" again. It's embarrassing.

Answer 9

Remember in science that theories are explanations of facts, not guesses.

Our sun will last for another 5 billion years. Then it will turn into a red giant, and then ultimately collapse into a white dwarf. This can be calculated by looking at the current percentage of hydrogen/helium/heavier elements (such as carbon) in the sun. The sun releases energy through nuclear fusion (two hydrogen atoms fuse into one helium atom, three helium atoms fuse into one carbon, etc.). As a percentage of lighter atoms are fused into heavier atoms, the gravitational parameters of the sun will change and thus it will change into a red giant, then white dwarf.

Answer 10

Do you believe science is a set of rules repeatable in every part of our universe? If so, then our sun is so like many other stars in the galaxy. And there are so many of these stars, we can find them spread out at various places in their life span. We know they and their planets coelesce out of a hydrogen and dust disk. We know they live about 10 billion years before they exhaust their fuel. We can calculate this based on energy output and the amount of hydrogen they start with. We know they bloat into red giants and then become a planetary nebula. (see "helix nebula" in googe to see the closest such nebula to Earth.)

So, yes, if science and math are universal, we know we are about halfway thru the sun's 10-12 billion year life cycle.