Lake Afton Public Observatory

Ask An Astronomer - Archive of Solar System Questions


Q1.
Are there volcanoes on other planets or moons beside Mars and Earth, if so where?

Q2.I would like to find a site on the Net that can give me a picture and other information of the asteroid ZappaFrank (3834).

Q3. Recently astronomers have found evidence for the existence of water around stars, planets, and on the moon Titan. How much water was found on Titan, and what are the implications for life on the satellite now that water has been discovered?

Q4. How does Venus keep from exploding if it is made of gas?

Q5. Do the planets revolve around the sun in a clockwise or counterclockwise direction?

Q6. I would like to know how big you think the new planet N A S A has found, orbiting Proxima Centauri.

Q7. Why is the Sun important? and why is it important to the Earth?

Q8. We are learning about the solar system in science. My mom said she thought that there were new planets discovered - like one called Vulcan, but she can't find anything about it now. My teacher says there is no such thing in this solar system. Has any other planet been found out there? Thanks!

Q9. I was wondering since Pluto and Neptune have orbits that cross each at some points two if I am not mistaken, what are the odds of a planetary collision? A friend and I have a difference of opinion on whether or not this could actually occur?.

Q10. How is an asteroid created?

Q11. Is there water on the Moon?

Q12. Why does Saturn have rings round it?

Q13. Why is our moon only called 'the Moon'? Why doesn't it have a special given name? I know that other cultures historical names did not stick, like Luna, Selene. Other planets moons have given names, like 'Io and Europa-moons of Jupiter', but our has no other name other than the Moon. Why is this so?

Q14. Since Pluto is approx 6 billion km away from the Sun, shouldn't the solar system be 12 billion km wide rather than 2 light-year=2000 billion km wide, as I've just read?

Q15. When we celabrate the new year where are we in space relative to the sun?????


Q1. Are there volcanoes on other planets or moons beside Mars and Earth, if so where?

A1. Jupiter's moon Io has active volcanoes! Venus has volcanoes that are active - nobody is really sure if they are active or not. Neptune's moon Triton has geysers of liquid nitrogen. Other solar system moons have had ice or water vulcanism. On these frigid moons water is the lava. You can learn more about all this hot stuff from the Nine Planets at:

http://seds.lpl.arizona.edu/nineplanets/nineplanets/nineplanets.html

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Q2. I would like to find a site on the Net that can give me a picture and other information of the asteroid ZappaFrank (3834).

A2. First off, you aren't going to find any interesting pictures of this asteroid. Since this asteroid has not been visited by a spacecraft it will look like a streak of light on a photo of a starry background. I found such a photo of this asteroid at

http://mama.indstate.edu/users/jchook/astro/archive.html

Information on the orbit of this and other asteroids can likely be found at

ftp://ftp.lowell.edu/pub/elgb/astorb.html

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Q3. Recently astronomers have found evidence for the existence of water around stars, planets, and on the moon Titan. How much water was found on Titan, and what are the implications for life on the satellite now that water has been discovered?

A3. Perhaps you know of something that I don't. I know of no discovery of liquid water on Titan. Titan is likely made up of about half frozen water and liquid water is quite unlikely since its surface temperature is thought to be -290 F.

The only moon that sounds anything like your description is Jupiter's moon Europa. Europa is thought to have a solid rocky core that is sourrounded with a liquid water ocean and an icy crust. Nobody knows how thick the icy crust is, but it seems that liquid water flows or erupts to the surface from time to time. If this ocean has been liquid since the formation of Europa it would seem to me that there is a chance of life there.

For more on Titan see:

http://seds.lpl.arizona.edu/nineplanets/nineplanets/titan.html

For more on Europa see:

http://seds.lpl.arizona.edu/nineplanets/nineplanets/europa.html

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Q4.How does Venus keep from exploding if it is made of gas?

A4. Venus isn't made of gas. It is a rock planet like our Earth. Venus does have a dense carbon dioxide atmosphere. Carbon dioxide is not a flammable gas.

The outer gas planets of Jupiter, Saturn, Uranus, and Neptune do have substantial amounts of hydrogen in their atmospheres. Hydrogen here on Earth is extremely flammable - explosive in fact. But there is no oxygen in the atmospheres of these worlds to combust with and so they can't explode.

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Q5. Do the planets revolve around the sun in a clockwise or counterclockwise direction?

A5. Hold up your right hand in the "thumb up position". If your thumb is pointing north the fingers curl around counterclockwise. This is the direction that our Earth rotates, the direction that the Moon orbits about our Earth and the direction that all the planets orbit about our Sun.

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Q6. I would like to know how big you think the new planet N A S A has found, orbiting Proxima Centauri

A7. Well, we really don't know what, if anything, was seen by the Hubble Space Telescope near Proxima Centauri. It is possible that they have directly imaged a large planet or possible a brown dwarf. Further observations are necessary to confirm or reject any possible finding. A nice article from New Scientist on this can be found at:

http://www.newscientist.com/ns/980131/nstar.html

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Q7. Why is the Sun important? and why is it important to the Earth?

A7. The Sun is our star. Our Earth, and all the life on it, gets its heat and light from the Sun. Without the Sun Earth would be a dead, frozen world.

The Sun is also important because it is the closest of all the stars. Much of what we know about the stars comes from what we know about our own star - the Sun. By studying our Sun and then comparing it to the other stars we can learn about them as well.

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Q8. We are learning about the solar system in science. My mom said she thought that there were new planets discovered - like one called Vulcan, but she can't find anything about it now. My teacher says there is no such thing in this solar system. Has any other planet been found out there? Thanks!

A8. As for our own solar system, it is just the nine planets that everyone knows about. Years ago, people at various times observed what they took to be a planet closer to the Sun than Mercury which was called Vulcan. No observations of this were ever confirmed and it does not exist.

Lots of information on this can be found at

http://seds.lpl.arizona.edu/nineplanets/nineplanets/hypo.html

Astronomers are just now learning how to detect planets around other stars. None of them can be imaged yet and all are being found via indrect means.

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Q9. I was wondering since Pluto and Neptune have orbits that cross each at some points two if I am not mistaken, what are the odds of a planetary collision? A friend and I have a difference of opinion on whether or not this could actually occur?.

A9. The odds of a collison between Neptune and Pluto are zero. Yes, the orbits cross when viewed from above but if you look at them from the side you will see that they are really no where near each other at this point. The highly tilted orbit of Pluto carries it far out of the plane of the orbits of the other planets including Neptune.

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Q10. How is an asteroid created?

A10. Asteroids are the rocky leftovers from the formation of the solar system. They are the solid debris that didn't from into planets. Our solar system contains many thousands of asteroids with more being discovered all the time. Most (but certainly not all) of them are scattered about between the orbits of Mars and Jupiter. As the solar system was formeing the gravitational pull of Jupiter helped to keep these bodies from pulling together to form a planet.

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Q11. Is there water on the Moon?

A11. Nobody is sure if there is water on the Moon or not. A space probe named Clementine found, in 1994, evidence of water ice at the Moon's dark shadowed south pole. One would only expect to find water ice on our Moon in areas like those at the poles that are always in shadow. The Moon has no air and it gets pretty hot during the day so water can't easily stay on the Moon.

If we wanted to live on the Moon it would be very helpful to find water ice already there as water is very heavy and expensive to lift off of Earth.

More recently (1998) a space probe called Lunar Prospector has confirmed the findings of water at the Moon's south pole and also found some at the Moon's north pole. All together Lunar Prospector found somewhere between 10 to 300 million tons of water ice scattered inside the craters of the lunar poles. To many's surprise, Prospector detected nearly 50% more water ice in the north than in the south.

Some Lunar Prospector scientists caution that direct confirmation of these findings is still needed.

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Q12. Why does Saturn have rings round it?

A12. Nobody is exactly sure why Saturn has rings. We do know that all of the big gas planets (Saturn, Jupiter, Uranus, and Neptune) have rings. Saturn's of course are the most impressive because they have the most material in them. Possible ideas for the rings at Saturn include the idea that a moon of Saturn may have been shattered by an impact, the rings formed along with Saturn itself, and going along with the first two the rings keep getting new particles from dust and other debries blasted off of the moons from the impact of meteorites, comets, etc.

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Q13. Why is our moon only called 'the Moon'?

A13. Yes it was called Luna by the Romans, Selene and Artemis by the Greeks, and many other names in other mythologies. But it seems that most of us, including me, just call it the Moon. Many folks don't capitalize the M in Moon though. You will find that many people also don't capitalize the E in Earth. It seems tom that these are their names so I always capitalize Moon, Earth, and Sun.

I don't really know why this is. People and thier rules for language can be strange, can't they?

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Q14.Since Pluto is approx 6 billion km away from the Sun, shouldn't the solar system be 12 billion km wide rather than 2 light-year=2000 billion km wide, as I've just read?

A14. There are many ways of defining the size of the solar system. One way would be to use the size of Pluto's orbit. Another would be to use the location of the comet's within the Sun's Oort cloud. Careful orbital calculations done in 1950 by Jan Oort indicate that a huge spherical "cloud" (now called the Oort Cloud) of perhaps a trillion (1e12) or more comets orbit the Sun far beyond the orbit of Pluto from about 30,000 AU to a light-year or more. This would produce the two light year figure that you quoted above. Yet a third way would be to mark the edge of the Sun's influence on space. Here we are talking about where the Sun's solar wind (the charged particles that stream outward from the Sun) meets the stellar wind from nearby stars. We aren't sure just yet where that boundry lies.

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Q15.When we celabrate the new year where are we in space relative to the sun?

A15. As you may know our orbit about the Sun isn't quite a perfect circle so some times we are a bit closer to the Sun and sometimes we are a bit farther from the Sun. Our closest approach to the Sun is known as perihelion and it occurs just a few days after New Year's Day. This year (1998) we were at perihelion on January 4th.

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