Real science Q? about an Arthur C. Clarke plot point

In 2010 The Odyssey Two, the monoliths turn Jupiter into another star.

How? I assume the monoliths had to change the mass of Jupiter, because it wouldn’t be able to sustain fusion at it’s current mass. Is this a valid assumption? How much mass would Jupiter have to gain?

Now that Jupiter is Jupiter/Sol II, how have things changed on Earth? With it’s changed mass, did it alter our path around Sol I, thus changing our year and seasons? What happens to our Moon in this new dynamic? What do our days and nights look like?

What type of NASA missions would be needed to further our understanding of this new mini Solar System inside our existing Solar System?

Would Voyager and Pioneer now qualify as interstellar probes?

Yes, I know it’s fiction. I’m pretending it happened for the sake of the questions.

Mass doesn’t come out of nowhere, so I’m certain that the monoliths didn’t increase Jupiter’s mass. My impression was that they somehow collapsed Jupiter into some ultra-dense form of matter so that it became a kind of mini white dwarf. The novel briefly mentioned that this disrupted nocturnal species on Earth, but would otherwise have no effect.

Things significantly smaller than Jupiter can achieve the pressures and temperatures necessary for fusion. They’re called H-bombs.

IIRC, some of the smallest red dwarfs are approximately the dimensions and mass of Jupiter. (Presumably they were somewhat heavier when they “ignited” – began core fusion.)

Jupiter is somewhat below the necessary mass to achieve the necessary temperatures and pressures – but it would not take a great deal, in cosmic terms, additional compression and/or temperature rise in its core to bring it to a point where fission can sluggishly begin. (Note that the “surface temperature” of Jupiter is 100 degrees Celsius higher than what it would be if all energy affecting it was the insolation it receives at that distance from the Sun; this is attributed to the energy released by its own gravitational contraction under current theory.)

It would be my assumption that transforming Jupiter into Lucifer in the story would be a matter of the monoliths causing that additional compression/rise in temperature (they’re co-equal effects) necessary to ignite fusion.

Voyager and Pioneer are now interstellar probes – though we don’t expect to get any results from them, since they won’t reach anywhere worth reporting back from for at least 10,000 years. But my assumption is that “interstellar probe” describes a probe sent from one solar system to investigate another (allowing for the case of a ‘solar system’ consisting only of one star and no planets, the minimal case, and ignoring the slight solecism of ‘solar system’ to describe another star and its planets, since ‘stellar system’ has a slightly different meaning involving the H-R diagram IIRC). That a given solar system might involve a double or multiple star, as ours would if Jupiter became Lucifer, does not constitute a separate entity to which an interstellar probe would be launched. (But some new terms would need to be invented to describe the situation.)

The effects of Lucifer (assuming no mass increase) on Earth are quite accurately drawn out by Clarke in 2010: Odyssey Two and 2061: Odyssey Three.

Interesting question and approach to the problem raised by the story, though!

Lucifer! I had forgotten the name.

Just thinking space stuff while I was working outside today. I guess because of Columbia. I drove by a fire station with a flag at half staff.

Sure, H-bombs attain fusion, but sustaining it is a little different, isn’t it?

Have the probes passed the Heliopause? Cool.

Nope. Not yet. But NASA’s Voyager web page says the craft should hit the “termination shock” sometime between 2001 and 2003, so it could happen any day now.

Here’s a page on the current status of Pioneer 11, which continues to be tracked. http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNStat.html
Pioneer 10 moved out of position for radio contact with Earth back in 1995.

And here is a page on the Voyagers, which are still very healthy and expected to last long into the 21st century:
http://voyager.jpl.nasa.gov/

Voyager 1 has passed both Pioneers despite the long head start they had is now the most distant man-made object.

In the books, the monoliths started making copies of themselves out of Jupiter’s matter - they were Von Neumann (sp?) devices. When enough of Jupiter had been converted into rather dense monolith, it collapsed and was able to begin a sustaining fusion reaction.

I’m fairly sure you can’t just compress an arbitrarily small mass of helium down enough and expect it to become a stable fusion-burning star, or a white dwarf (you could make a black hole, though). It wouldn’t remain in hydrostatic equilibrium (which is what distinguishes a star from a bomb). The smallest red dwarfs are around 0.08 M[sub]SUN[/sub], or about 80 times the mass of Jupiter. Mass loss for these lightweights is not a big issue, especially not yet, since the universe isn’t old enough for them to have evolved.

As for whether Lucifer is another star system, I would say no. Jupiter and the Sun have a tighter orbit than lots of systems we consider binaries.

If Jupiter’s mass remained the same, it would not affect our trajectory around the Sun. Or the moon’s. Or its, for that matter.

How would our nights look? Well, lighter stars are less luminous. For the main sequence, luminosity is roughly proportional to mass[sup]3.5[/sup]. Of course, the main sequence doesn’t go down to Jupiter’s mass, but if we extend it, we can get Lucifer’s luminosity as 1e23 erg/s. This means at closest approach, Lucifer would have an apparent magnitude of 3.5, which is dimmer than it is now. Thus we would still be getting more sunlight reflected off Lucifer than we would be getting Luciferlight.

Thanks, Achernar, for some specifics. (Thanks to the others, too, you know, really. I just love this kind of stuff!)

But, what if Lucifer and Jupiter weren’t the same mass? What if Jupiter had to increase in mass to become Lucifer? Assume the lowest amount needed. Then, what would be Lucifer’s apparant magnitude?

Cool links, fiddlesticks

A 0.08 M[sub]SUN[/sub] star where Jupiter is would be around -13th magnitude. About the same brightness as the full moon.