Astronomy Questions?

[gerry_mania]

My sister needs help with her astronomy homework. I was wondering if any of you knew the answers so i could help point her in the right direction?
1. How do you think the seasons would be different if Earth were inclined 90 degrees instead of 23.5 degrees? 0 degrees instead of 23.5?
2.Are there other planets in our solar system from whose surface you could see a lunar eclipse? A total solar eclipse? Which ones and why?

Any help you could give would be greatly appreciated. And please if you dont know the answer or dont know how to get the answer please dont respond.

[Brant]

Your sister? Well, okay then.
If the axis was inclined 90 degrees, the seasons would be catastrophically extreme. The equatorial regions would get cooler because the sun will range much farther north and south. At the northern summer solstice, the north pole would be the hottest place on earth. The south pole would be the coldest. Then that would reverse six months later. The vast and relatively sudden differences in temperature would certainly cause storms like we have never seen. Almost all of the vegetation would die off, outside of the tropics because of weeks to months of almost total darkness. Huge numbers of species of animals would become extinct because of the drastic changes in environment.

If the axis was at zero degrees, we wouldn't have any seasons at all. The tropics would become insufferably hot, causing widespread disaster.

You could see lunar eclipses from all the planets except Mercury and Venus. From Jupiter, you would see moons moving into the planet's shadow nearly every day. The question about total solar eclipses is harder. You have to consider the apparent sizes of the moons and the sun from the planets' distances outward. For example, the sun might be so small from Neptune that Triton would be able to block it completely. I'll check some of the others and get back to you. (If I suddenly get 3 or more thumbs down, it is because someone has been sabotaging all my answers for three days now, using multiple accounts.)

Edit: Titan should be big enough to cause total solar eclipses on Saturn. I know that some of Jupiter's moons can cause total eclipses because I have seen pictures of their shadows on the surface of the planet. The shadows would not be nearly so dark if they were only partial eclipses. Note: total solar eclipses would NOT be caused by every moon for every planet -- only partials and annulars. *Total* solar eclipses are harder to figure.

As Mercury and Venus have no moons, they will not see any kind of eclipse.

[quantumclaustrophobe]

1. Well, at 90 degrees, each hemisphere would get months of nothing but sun, followed by months of nothing but dark....

At 0 degrees, there wouldn't *be* any seasons - or not much, anyway, as everywhere on Earth we'd get 12 hours of day, and 12 hours of night.

2. Well, you could see lunar eclipses on Jupiter, Saturn, and Neptune; A total solar eclipse would be an everyday occurance on Jupiter and Saturn - the planets are so big, that the moons *have* to eclipse the sun (and likewise, the orbit of the moon would take it through the shadow of the planet) on just about every orbit. Also, the sun is so far away, that total solar eclipses are easy - as the moon appears much larger being so much closer to the planet.

[Michael Steen]

I also agree that total solar eclipses would be common on Saturn and Jupiter, given the small size of the sun and the large size of the moons.
However, I think that our Earth/Moon/Sun combination is probably the only one in the solar system where the moon fits so perfectly over the sun that it leaves the coronal ring shining out around the moon's perimeter. The sun is 400X bigger than the moon, yet conveniently 400X farther away, making a nearly perfect match.
Titan would eclipse the sun on Saturn, true, but you'd see nothing of the sun behind it.