Why Will Sun Get Hotter?

[Westwind]

I've read that scientists believe the Sun's temperature increases by about 10 percent every billion years or so. In about a billion years, they estimate the Sun will get so hot that it will boil away the oceans on Earth.

What is causing the Sun's temperature to increase over time?

--Bill

[BMAONE23]

Some of it might have to due with the fusion process and the fact that Fusing heavier elements requires/creates greater heat

[Chris Peterson]

I've read that scientists believe the Sun's temperature increases by about 10 percent every billion years or so. In about a billion years, they estimate the Sun will get so hot that it will boil away the oceans on Earth.

What is causing the Sun's temperature to increase over time?

The Sun is (currently) producing its energy by fusing hydrogen into helium. Helium is denser than hydrogen, and sinks to the core. This results in greater gravitational compression, which is offset by a greater rate of fusion to maintain a balance.

In general, over the main sequence lifetime of a star, the gradual increase in helium results in a corresponding increase in fusion rate, and therefore a gradual increase in temperature.

[Westwind]

Thanks very much, Chris.

I've volunteered to give a presentation about the Sun for our astronomy club at a county park system nature center next month. I plan to discuss the life cycle of the Sun, mentioning that the Sun will become hotter over time, etc.

I figure someone in the audience might ask why the Sun will become hotter, so I want to be prepared. I'm an amateur astronomer, so preparing my PowerPoint presentation has been a enjoyable learning process for me.<s>

Thanks again.

--Bill
Cuyahoga Astronomical Association

[Orca]

You might try comparing the life sequences of low, medium (like our sun), and high-mass stars. Initial mass is a critical factor in the life cycle, behavior, lifespan, and of course death of a star.

[Vaccum Explorer]

I s this another Globle Warming Story

[Westwind]

Thanks for your suggestion, Orca.

--Bill