2010

[tigerlily11]

I was watching 2010 the other night and it set me wondring.
If Jupiter were to turn into a sun what would be the effect on Earth?
What would having a second sun do to us in the way of climate, and gravity? Would we be pulled towards Jupiter?
Thanks or your time.

[Rabelais]

As Jupiter would be unchanged in mass we sould be unchanged in respect to gravitational effects. It is this overall mass that makes Jupiter unable to become a star. If Jupiter were to become a star it would need to absorb a significant mass. I do know it has been calculated that if Jupiter had been a star then life would never have formed on earth due to the increased radiation.

[jake-the-peg]

I'm not convinced that that is necessarily right about life never forming if we were part of a binary star system. Where did you hear that?

We still haven't quite worked out how the first life formed so we don't know how critical increased heat or light might have been in the process.

Perhaps the first life formed in cracks in rocks well shielded from light - certenly there are modern bacteria that are able to survive in the most extreme environments and would be able to survive if Jupiter had been a star.

Incidently the smallest star ever found is only 16% larger than Jupiter but 96 times it's mass.

If we were part of a binary system, a lot would depend on our orbit. You could for example conceive of a system where we are at the center of 2 orbiting stars in which case you'd always have daylight

[jno]

if the present sun was as close as Jupiter we'd be quite warm, wouldn't we?

[jake-the-peg]

not sure I understand jno

Earth's orbit is 93 million miles from the sun, Jupiter's is 483 million miles from the sun.

If the sun were as far away from us as jupiter is we'd be pretty chilly.

Or did you mean an additional sun there?

BTW this is what the sun looks like from Jupiter http://www.nsf.gov/news/mmg/media/images/55_ca ncri_f.jpg

OK that's a bit further away, I'm not sure another sun at that distance would have a gigantic effect.

The sun has a bit of an effect on the tides (springs and neaps) but if it were 4 times further away that'd be 16 times smaller - measurable but no big thing

[jno]

sorry, jake, you're quite right of course - I was imagining it expanding from its present centre, but managed only to move a decimal point in the wrong direction

[Teddio]

If Jupiter became a star its mass wouldn't changed therefore the orbit of Earth would be unchanged. The apparent diameter of Jupiter is about 0.4 arc minutes whilst that of the Sun is about 30 arc minutes. If the surface temperature of Jupiter were the same as the Sun's then the amount of extra electromagnetic radiation would be quite small.

[tigerlily11]

I assume we are further from the Jupiter than from the sun. I'm finding this interesting but I'm not very good at understnading arc minutes and so on.
But I like to learn.
I understood from the film that the mass of Jupiter would have to change from what it is now so it can become a sun.
I thought that having two suns in our solar system would it would be rather on the hot side.
The other thing that the film showed was the moons of Jupiter not just becoming planets, but livable planets. Are they not a little to close to become livable planets?

[NiceCupOfTea]

Please read Asimov's 'Nemesis' if you haven't already.

I reckon you'll love it.

[jake-the-peg]

Your right tigerlilly,

Stars start to burn when the pressures and temperatures at their centres become great enough for hydrogen to be turned into Helium, what we call nuclear fusion.

Jupiter just hasn't the wherewithall, infact a commonly used figure is something like 75 times the mass of Jupiter for ignition.

The 4 so called Gallelian sattelites are very interesting, Io, the closest to Jupiter is a real Hell world full of volcanoes and lava plumes it's constantly being heated by Jupiter's pull
http://starchild.gsfc.nasa.gov/docs/StarChild/ solar_system_level2/io.html

But Europa is really interesting, it's covered in ice but there's good reason to think there might be liquid water beneath it. Now we've aleady discovered life on earth miles below the ocean living off of volcanic plumes so it's just conceivable that you might find the same on Europa.

There's a great page on this here:
http://www.resa.net/nasa/europa_life.htm unfortunately it's a little out of date now as the proposed mission to melt through and explore beneath the ice was cancelled in 2005