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Jimi Hendrix
2003-Jan-20, 08:16 PM
Which moon other then OUR moon, do we know the most about?

Which planet other then OUR planet do we know the most about?

When are we going to send more probes to probe the outer gass giant planets such as Uranus? What about the inner planets such as venus? I heard Mercury was going to be probed in 2004. Is this still in developemnt?

How often do astronomers find new objects in the Kupier belt?

I heard that Jupiter has recently been discovered as having another moon? How often do we find new moons around Jupiter?

Is it a common thing to find new moons around the planet Jupiter frequently?

What planet is the oldest?

GrapesOfWrath
2003-Jan-20, 08:24 PM
On 2003-01-20 15:16, Ritchie Blackmore's cousin wrote:
I heard that Jupiter has recently been discovered as having another moon? How often do we find new moons around Jupiter?

Is it a common thing to find new moons around the planet Jupiter frequently?
Lately, yes. David Hall posted some information in this thread: 40 and counting! (http://www.badastronomy.com/phpBB/viewtopic.php?topic=3393&forum=2)

AstroMike
2003-Jan-20, 08:45 PM
On 2003-01-20 15:16, Ritchie Blackmore's cousin wrote:
Which moon other then OUR moon, do we know the most about?

I think not just one moon, but Jupiter's four Galilean Satellites we know more about beside our Moon.


Which planet other then OUR planet do we know the most about?

That's a matter of opinion, but probably Mars IMO.


When are we going to send more probes to probe the outer gass giant planets such as Uranus?

Not sure.


What about the inner planets such as venus? I heard Mercury was going to be probed in 2004. Is this still in developemnt?

Yes, Messenger (http://sse.jpl.nasa.gov/missions/merc_missns/merc-msgr.html) is scheduled for launch in March or May in 2004. It will conduct a better scientific analysis of the geology and geochemistry of Mercury's surface than Mariner 10 (http://sse.jpl.nasa.gov/missions/merc_missns/merc-m10.html) did.


How often do astronomers find new objects in the Kupier belt?

Not exactly sure.


I heard that Jupiter has recently been discovered as having another moon? How often do we find new moons around Jupiter?

Is it a common thing to find new moons around the planet Jupiter frequently?

Not until 1999 when the Spacewatch program discovered Callirhoe (S/1999 J1) (http://cfa-www.harvard.edu/iauc/07400/07460.html), 20 years after Voyager discovered the inner satellites Metis, Adrastea, and Thebe (http://sse.jpl.nasa.gov/features/planets/jupiter/metis.html).


What planet is the oldest?

Don't know.

JS Princeton
2003-Jan-21, 12:38 AM
All the planets are just about the same age.

Uranus was a big disappointment. I bet we go to Pluto or Neptune before heading back there.

Jimi Hendrix
2003-Jan-21, 12:41 AM
On 2003-01-20 19:38, JS Princeton wrote:
All the planets are just about the same age.


What do you base this comment on?

Senor Molinero
2003-Jan-21, 01:18 AM
WRT the age of the planets, I would suspect that the heavier elements would coalesce and stabilise before the lighter elements. Hence, they probably formed in the order of innermost to outermost. Pluto and the KBOs are another story. Toss a coin.

aurorae
2003-Jan-21, 05:23 AM
IIRC, they are now finding hundreds of Kuiper Belt objects per year.

JS Princeton
2003-Jan-21, 06:07 AM
On 2003-01-20 19:41, Ritchie Blackmore's cousin wrote:


On 2003-01-20 19:38, JS Princeton wrote:
All the planets are just about the same age.


What do you base this comment on?


Meteorites mostly. That's how scientists genearlly date the solar system. Here's the thing, the solar system itself is pretty much a coherent object in terms of makeup. There's not much coming in and there's not much going out. One telling clue that everything is probably the same age is that there is a plane of the ecliptic. Also, all the planets also go around the same direction (except for one). There are also a lot of clues about coherence of the solar system's bodies. For example, chemical abundances throughout the solar system are surprisingly uniform. Planetary system formation theory still holds that the entire system is formed from the collapsing circumstellar disc. For some reason, the big gas giant in our galaxy was pushed out to Jupiter's orbit. We don't know the details well, but the overarching story is pretty much clear.

Jimi Hendrix
2003-Jan-21, 10:59 PM
On 2003-01-20 19:38, JS Princeton wrote:
Uranus was a big disappointment. I bet we go to Pluto or Neptune before heading back there.


Why?

The Shade
2003-Jan-22, 12:02 AM
Not to bash anyone, but I find all planets have very interesting things to offer.

About Uranus, why is it interesting? Well, all the other gas giants radiate more energy than they receive from the sun. So, why not Uranus? That's an interesting question, and I wish I could answer it: that's why I'm fascinated by this planet. It's moons are all geological puzzles, especially Miranda.

I could go on and on, but this is putting me in the mood to go read "The New Solar System: Fourth Edition". See ya later...

JS Princeton
2003-Jan-22, 01:47 AM
Unlike Jupiter and Neptune which had strange surface features and Saturn which has a ring system, Uranus is somewhat dull. No surface features, a boring ring structure. All it has going for itself is it has lots of moons and is a bit peculiar in its axial tilt, but golly-gee, Miranda pales in comparison to Neptune's Triton, Saturn's Titan or Jupiter's Europa and Io as an interesting moon. I agree that Uranus has its moments, but I bet Pluto is next on the docket... there's a lot of buzz to that effect anyway.

Jimi Hendrix
2003-Jan-22, 02:04 AM
How long would it take to send a probe down Pluto's neighborhood?

Jimi Hendrix
2003-Jan-22, 02:06 AM
probe Uranus. LOL Sorry. Couldn't help it.

ToSeek
2003-Jan-22, 06:57 PM
On 2003-01-21 21:04, Ritchie Blackmore's cousin wrote:
How long would it take to send a probe down Pluto's neighborhood?


New Horizons (http://pluto.jhuapl.edu/journey.htm) expects to take nine years for the trip, launching in 2006 and arriving in 2015. That's taking advantage of a Jupiter flyby. A direct flight would take even longer.

_________________
"... to strive, to seek, to find, and not to yield." - Tennyson, Ulysses

<font size=-1>[ This Message was edited by: ToSeek on 2003-01-22 13:57 ]</font>

David Hall
2003-Jan-22, 07:24 PM
One problem is, the faster you can get it there, the faster it's going to fly by the planet, and the less actual science you can do. It would cost too much or take too long to actually do a leisurely stroll by the planet.

ToSeek
2003-Jan-22, 07:48 PM
On 2003-01-21 21:06, Ritchie Blackmore's cousin wrote:
probe Uranus. LOL Sorry. Couldn't help it.


Speaking of Uranus, here's a cool new photo (http://SkyandTelescope.com/news/current/article_846_1.asp)

Jimi Hendrix
2003-Jan-22, 11:15 PM
It's a picture of my Uranus.

Rodina
2003-Jan-22, 11:26 PM
Maybe I'm horribly immature, but Uranus jokes just never get tiring.

Somewhere on NASA's wish list, I think, is a desire to a Neptune orbiter like Cassini or Galileo. But I'd rather get back to Europa, first.

xriso
2003-Jan-23, 05:40 AM
On 2003-01-21 01:07, JS Princeton wrote:

Meteorites mostly. That's how scientists genearlly date the solar system. Here's the thing, the solar system itself is pretty much a coherent object in terms of makeup. There's not much coming in and there's not much going out. One telling clue that everything is probably the same age is that there is a plane of the ecliptic. Also, all the planets also go around the same direction (except for one). There are also a lot of clues about coherence of the solar system's bodies. For example, chemical abundances throughout the solar system are surprisingly uniform. Planetary system formation theory still holds that the entire system is formed from the collapsing circumstellar disc. For some reason, the big gas giant in our galaxy was pushed out to Jupiter's orbit. We don't know the details well, but the overarching story is pretty much clear.


I've heard a theory that the gas giants formed further out, then slowly "fell" inwards. Is this possible?

The Shade
2003-Jan-23, 04:43 PM
On 2003-01-22 18:26, Rodina wrote:
Somewhere on NASA's wish list, I think, is a desire to a Neptune orbiter like Cassini or Galileo. But I'd rather get back to Europa, first.


Same here. That moon is just too fascinating to ignore. But a couple of more orbiters for Uranus and Neptune would be great, but would take way too long to get there, unless we develop some new propulsion method to accelerate them when leaving Earth and accelerate (decelerate) them when arriving at their destination.

Yes, I do like to read about Uranus and Neptune, but what can I say, I like to further my solar system knowledge about planets that don't get too much attention.

Anonymous
2003-Jan-23, 05:35 PM
xriso.


I've heard a theory that the gas giants formed further out, then slowly "fell" inwards. Is this possible?


There are models which address both inward and outward orbital migration of planets. The inward models focus primarily on pre-ignition star systems and the outward models focus on post-ignition. (Ignition of the star, commencement of T-Tauri winds)


Examples of pre-ignition model;

http://physicsweb.org/box/world/14/1/7/pw1401073


http://www.astro.su.se/~pawel/blois/talk_3.1.html


http://www.astronomynotes.com/solfluf/s12.htm


http://www.lpi.usra.edu/meetings/dps97/html/H2807/H2807.html


Post-ignition or outward migration model;


http://www.aas.org/publications/baas/v30n4/aas193/751.htm


http://www.fiz.huji.ac.il/~lazar/PLUTINO.HTML