[evan_au (OP)]

From Europan Ocean: Is the sun heating so fast that within 2000 years life as we know it on Earth will not be possible?

[Split off from: "Liquid metal core of the Earth, is cooling?" - moderator]

[evan_au (OP)]

The Sun undergoes an approximately 11-year magnetic/sunspot cycle, affecting sunspot numbers. Measurements have shown that the Sun's total energy output varies around 0.1% during this cycle. From this we could deduce that there is no real trend in the Sun's output on a scale of a decade.

There are discussions about whether longer-term cycles in the Sun's output occur which could affect the Earth's temperature (like the Maunder Minimum). However, Galileo only used the telescope to study the sunspots about 400 years ago, with the Chinese doing some naked-eye observations prior to this, so we aren't sure about the Sun's long-term behaviour. In recent years we have started to do Helioseismology, which allows us to peer into the Sun's internal temperature and pressures. All we really know is that the Sun's behaviour is somewhat chaotic.

I would be surprised if the Sun's output is increasing rapidly enough to cause the Earth to become uninhabitable in 2,000 years - the best evidence for this would come from the numerous satellites now observing the Sun directly, rather than from Earth-based observations which must contend with the changeable and distorting lens of Earth's atmosphere.  I'm sure if the satellites had discovered such a trend, it would have been well-publicised. Please post a link to the source of this prediction (it's not a Climate-Change Denial website, is it?).

On much longer timescales (like 5 Billion years), the Sun is burning its hydrogen fuel, and when this is almost complete, the Sun will move to burning Helium, and it is expected to become a Red Giant star. This will make the Earth too hot to be habitable in its current orbit. See: http://en.wikipedia.org/wiki/Sun#After_core_hydrogen_exhaustion

[yor_on]

Haven't read that article yet but I sincerely doubt that conclusion. People have been using the sun for claiming all sorts of things, but it's been here for the whole of evolution And that's quite some time. Those not liking the idea of a man made warming will continue too look for other explanations, but the sun's variations is not enough, as far as I've seen.

[Europan Ocean]

Mellen Thomas has been saying things about physics and the future of people.

http://www.mellen-thomas.com/index.html

Also Hawking made the news that we need a new planet within a thousand years.

[yor_on]

Nah. think you can rest easy on that one. Global warming is real though, and there is no telling what the impact will be in some centuries, but we humans are resourceful, and able to learn from mistakes. We should be able to change our ways.