View Full Version here: : Is the Sun getting hotter?

17-01-2011, 04:37 PM

Our current science tells us that one day the Sun will become a red giant.

I have often wondered how gradual such a process is... could our "warming" be due to the Sun's inevitable fate?

No doubt some real science is now being undertaken with this project which may indicate the level of the Sun's culpability or absence thereof.

Still no doubt either side of the "climate change debate" will use the gathered data to grind their own axe.


17-01-2011, 06:38 PM
Yes it is! It is believed to be 30% hotter now than it was when it first became a main sequence star. This increase in heat will destroy life on our planet long before the Sun becomes a red giant. In a billion years or so there will be no water left on this planet.

17-01-2011, 06:41 PM

Is that a progression to helium burning (hotter reaction)?


18-01-2011, 03:36 PM
The Sun is not hot enough to fuse helium at the moment. It will not be hot enough until the after the Sun becomes a red giant and the helium core gets hot enough for helium fusing. A helium 'flash' will occur.

The reason the Sun is getting hotter is that as more and more helium is fused to helium the core contracts. Due to this the outer layers expand and increase in temperature. With a higher surface temperature and greater surface area it becomes more luminous.

18-01-2011, 09:36 PM
The surface temp of the Sun will go up a bit as it expands but not so dramatically that it will alter its spectral class too much. The main problem is whilst the core is filling up with helium ash, the outer layers of the Sun have to expand to accommodate the heating up of the core (as the ash builds up, the core slowly contracts and heats up). So, the Sun slowly increases its luminosity, hence we get more sunlight and it heats up here (and elsewhere in the Solar System).