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How many new moons will New Horizons discover?

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[Cosmos Magazine] Knocking on Pluto's door

20K views 370 replies 76 participants last post by  Algorithm 
#1 ·
Quote:
If all goes to plan, on 14 July at 11:50am UTC, a NASA spacecraft called New Horizons will pass within 10,000 kilometres of it [Pluto]. This is the last great voyage of discovery we're likely to see in the next 20 years - "the closing of the first era in planetary reconnaissance", in the words of Alan Stern, the mission's principal investigator.
Source

Finally, in a month and a half, New Horizons will arrive at Pluto. Of course, Pluto is only a dwarf planet now, but it still seems to have some important historical significance in Human planetary exploration. I'll keep posting updates to this thread until rendezvous time. Who would have thought you could get so excited about events happening more than 4 billion kilometres away?
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Unfortunately I'll be at a camp from July 5 to 10, but hopefully I'll be able to have internet access to keep up with the final approach. The actual rendezvous happens on July 14. Meanwhile, New Horizons scans for undiscovered moons and even rings. Hopefully it won't hit anything, but most planetary probes haven't. An impact at its current speed would be disastrous.
 
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#2 ·
This is exciting. I have been waiting for 15 years just for this lol. No seriously, I was. But to make time go by, I simply kind of forgot about it and recently in the past year, I have been keeping up on its progress to Pluto. Im sure we are going to find 2 more or even 3 more small moons. And while New Horizon is out there, Im sure we will see other dwarf planets around there.....ok maybe not alot but Im sure they are going find some other things out there.
 
#3 ·
Really can't wait to see what it uncovers... And to think how LONG it's been travelling...
 
#4 ·
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Originally Posted by -iceblade^ View Post

Really can't wait to see what it uncovers... And to think how LONG it's been travelling...
Not 15 years like rudyae86 said, but he probably meant that he'd been waiting for a Pluto probe in general as opposed to New Horizons in particular.
Quote:
Originally Posted by rudyae86 View Post

This is exciting. I have been waiting for 15 years just for this lol. No seriously, I was. But to make time go by, I simply kind of forgot about it and recently in the past year, I have been keeping up on its progress to Pluto. Im sure we are going to find 2 more or even 3 more small moons. And while New Horizon is out there, Im sure we will see other dwarf planets around there.....ok maybe not alot but Im sure they are going find some other things out there.
Yeah, they plan to target another Kuiper belt object after the Pluto flyby. I don't think they've selected one yet. Of course, space being so vast and all, there won't be anything major hanging around Pluto. You can pass the orbit of Pluto and still be billions of miles from the planet. In general, real asteroid belts are nothing like what you see in in Star Wars. If you are in orbit of a certain asteroid, say, Vesta, you won't be able to distinguish any other asteroids as anything other than points of light.
 
#6 ·
A lot of people were excited about Ceres, but for some reason I find Pluto to be many times more interesting. It's very very far, and Hubble couldn't even photograph it that well.
 
#8 ·
Voyager 1 could have been directed towards Pluto after it reached Saturn, but NASA decided to have it take a close-up look at Titan instead. Directing the probe toward Titan meant that they couldn't set up the right slingshot maneuver to go to Pluto. Voyager 2 never had any chance to get there, because of where Neptune was in relation to Pluto (Pluto was actually closer to the Sun and on the other side of Neptune's orbit in 1989) after its visit to Neptune.

Pluto has likely been essentially undisturbed since the very early days of the Solar System. It's in a 3:2 orbital resonance with Neptune, and that and its enormous orbital inclination relative to the ecliptic make it as much a backwater as a huge Kuiper Belt object can be. It's one reason we never found any other KBO's for decades; the other big ones are nowhere near where Pluto is.

I always hated they passed up Pluto in 1980 for a look at Titan, but we had to check out Titan. We should really be sending another mission there instead of wasting time wanting to explore irradiated Jovian moons, if they're looking for possible life. Plus, I'm not so sure Voyager 1 had good enough technology (launched in 1977) to really get a good look at Pluto. New Horizons does.
 
#9 ·
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Originally Posted by jsc1973 View Post

Voyager 1 could have been directed towards Pluto after it reached Saturn, but NASA decided to have it take a close-up look at Titan instead. Directing the probe toward Titan meant that they couldn't set up the right slingshot maneuver to go to Pluto. Voyager 2 never had any chance to get there, because of where Neptune was in relation to Pluto (Pluto was actually closer to the Sun and on the other side of Neptune's orbit in 1989) after its visit to Neptune.

Pluto has likely been essentially undisturbed since the very early days of the Solar System. It's in a 3:2 orbital resonance with Neptune, and that and its enormous orbital inclination relative to the ecliptic make it as much a backwater as a huge Kuiper Belt object can be. It's one reason we never found any other KBO's for decades; the other big ones are nowhere near where Pluto is.

I always hated they passed up Pluto in 1980 for a look at Titan, but we had to check out Titan. We should really be sending another mission there instead of wasting time wanting to explore irradiated Jovian moons, if they're looking for possible life. Plus, I'm not so sure Voyager 1 had good enough technology (launched in 1977) to really get a good look at Pluto. New Horizons does.
I agree, they should have skipped Titan. I mean its whole atmosphere is thick and nothing can be seen from above. I mean, it was not a bad idea, since they got information out of it and then sent Cassini to actually check it out years later.

Technology wise, Voyager was not going to do much other than a flyby on Pluto and with the little light the Sun sheds on Pluto, the optics of back then would have had a hard time trying to capture decent quality pictures. I know Im contradicting myself, sort of but the results of going to Titan were not that fascinating. I would have preferred if they went to another moon like one of Jupiters big moons instead.

Its crazy how the Voyagers are still emitting signals or relaying back signals to Earth, I mean...they aren't even close to the farthest side of the solar system....yet.

I think Im going to pee my pants when I see the first pictures of Pluto and its moons. Shoot, Im going to poo myself when they see a bit more of the other dwarf planet.
 
#12 ·


Pluto does looks like a strange place and I can't believe it has a small atmosphere on it.
 
#13 ·
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Originally Posted by bcham View Post

shame they cant stick a rocket on the Hubble and send it in to deep space.imagine the pictures it would send back 10 years down the line.
Ain't got the radio capability. The dishes on the outer probes are massive compared to the rest of the probe.
Quote:
Originally Posted by Neo_Morpheus View Post



Pluto does looks like a strange place and I can't believe it has a small atmosphere on it.
Spectrography (not sure if I spelled that right) showed some gas emission lines around Pluto. But the atmosphere is obviously very thin since Pluto has such a small gravitational field and apparently the atmosphere on the night side of Pluto freezes and falls to the ground. I don't think they've directly observed that, but if they know the temperature of Pluto by the inverse square law of distance to the sun and they know the composition of the gases, they can probably predict it.
 
#15 ·
I can support Pluto as a planet if they don't find anything else out there comparable to it and Eris. Both of them are quite a bit larger than the other so-called dwarf planets that we've discovered so far.

I think the definition of a planet that is currently being used is kind of stupid. As several scientists have pointed out, if you really went by the "letter of the law," then the Earth is not a planet, because the Moon, uniquely among Solar System satellites, is controlled more by the Sun than by Earth, and therefore the Earth hasn't "cleared its neighborhood." That's without even getting into the subject of the asteroid Cruithne.
 
#16 ·
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Originally Posted by Algorithm View Post

... Hopefully it won't hit anything ... An impact at its current speed would be disastrous.
I'm not too worried, NH is aimed to intersect the system at a point, close to Charon's orbital path, that enjoys "quick automatic cleansing" of potential debris.



And at current evaluation the risks seem to be very low.



But just in case they've planned several SHBOTs (Safe Haven By Other Trayectory) to dodge potential HazMat.

 
#17 ·
Quote:
Originally Posted by jsc1973 View Post

I can support Pluto as a planet if they don't find anything else out there comparable to it and Eris. Both of them are quite a bit larger than the other so-called dwarf planets that we've discovered so far.

I think the definition of a planet that is currently being used is kind of stupid. As several scientists have pointed out, if you really went by the "letter of the law," then the Earth is not a planet, because the Moon, uniquely among Solar System satellites, is controlled more by the Sun than by Earth, and therefore the Earth hasn't "cleared its neighborhood." That's without even getting into the subject of the asteroid Cruithne.
You're right. I think this calls for an amendment of "cleared its orbit" to "cleared its orbit of all significantly smaller objects." Have you ever heard of the rumours of a planet called Vulcan that has the same orbit as Earth but is exactly opposite Earth? Disproven, of course, by other planetary probes that stayed on one side of the Sun while Earth was in behind it.

As for Cruithne, it may have a clear orbit, but it is almost certainly not a perfect sphere due to its size, so it does not qualify as a planet.
 
#18 ·
Quote:
Originally Posted by Algorithm View Post

You're right. I think this calls for an amendment of "cleared its orbit" to "cleared its orbit of all significantly smaller objects." Have you ever heard of the rumours of a planet called Vulcan that has the same orbit as Earth but is exactly opposite Earth? Disproven, of course, by other planetary probes that stayed on one side of the Sun while Earth was in behind it.

As for Cruithne, it may have a clear orbit, but it is almost certainly not a perfect sphere due to its size, so it does not qualify as a planet.
No one thinks Cruithne is a planet, but it is a very unusual asteroid, whose average distance from the Sun is 0.997 AU. The Earth is unable to clear it, bring it under control as a moon, or force it into one of the Lagrangian points. It moves inside the Earth's orbit twice a year (although tilted so far from the ecliptic that it never is a danger to us), and is almost in a 1:1 resonance with the Earth--its orbital period is 364 days. Even ignoring the Moon's status, Cruithne technically disqualifies Earth as a planet under the current definition.

A correct definition of a planet would classify the Earth and Moon both as planets, due to the unique relationship they share. Current theory is that the Moon formed when a planet the side of Mars collided with Earth very early in its formation, and kicked out a ring of molten silicate rock that coalesced into the Moon.
 
#19 ·
Quote:
Originally Posted by jsc1973 View Post

No one thinks Cruithne is a planet, but it is a very unusual asteroid, whose average distance from the Sun is 0.997 AU. The Earth is unable to clear it, bring it under control as a moon, or force it into one of the Lagrangian points. It moves inside the Earth's orbit twice a year (although tilted so far from the ecliptic that it never is a danger to us), and is almost in a 1:1 resonance with the Earth--its orbital period is 364 days. Even ignoring the Moon's status, Cruithne technically disqualifies Earth as a planet under the current definition.

A correct definition of a planet would classify the Earth and Moon both as planets, due to the unique relationship they share. Current theory is that the Moon formed when a planet the side of Mars collided with Earth very early in its formation, and kicked out a ring of molten silicate rock that coalesced into the Moon.
I suggest adding a provision in the planetary definition that would define a pair of planets as a double planet or a planet and a moon depending on the location of the epicenter of their orbits. Seems to me I read that the Earth-Moon epicenter is just below Earth's crust but that Pluto-Charon's is somewhere in space between the two.
 
#20 ·
Quote:
Originally Posted by Algorithm View Post

I suggest adding a provision in the planetary definition that would define a pair of planets as a double planet or a planet and a moon depending on the location of the epicenter of their orbits. Seems to me I read that the Earth-Moon epicenter is just below Earth's crust but that Pluto-Charon's is somewhere in space between the two.
Based on that definition, which some have suggested, Pluto-Charon is a double planet (or double dwarf planet), but Earth-Moon is not. What you read is true. The barycenter of the Pluto-Charon system is outside of either body. The only other known objects in the solar system which have such a relationship are Jupiter and the Sun itself, and that only because of Jupiter's great distance from the Sun.

The reason I wouldn't advocate that definition of a double planet is based on that fact. In the future, when the Moon moves farther away from Earth, the barycenter will move outside the Earth and therefore "qualify" the Earth-Moon system under that definition. The only reason that it's below the surface of Earth at the present time is because the Moon is so ridiculously close to Earth, relatively speaking. There are no other solar system bodies where this is true; the movement of the secondary to create such a barycenter in any other case would result in the escape of the secondary body.

Back in the 1960s, Isaac Asimov offered a definition where any system where a primary and secondary body share the same orbit, and the solar attraction of the secondary is higher than that of the primary, it's a double planet. That qualifies the Earth-Moon system (0.46 ratio), but not Pluto-Charon. There are some dual asteroids by this definition, and some insignificant Jovian and Neptunian moons as well, but none of those objects are in hydrostatic equilibrium, and would therefore be disqualified as planets on that count.

The common sense resolution of this would be to say that any two bodies that qualify on either or both counts are a dual system, which would mean that both systems in question will always be dual (dwarf) planets at any time in the past, present, or future. In both cases, the secondary body is so large compared to the primary that you have to say that both Earth-Moon and Pluto-Charon are special cases. Neither system could exist if they were not defined by a different relationship than every other major satellite of a primary in the solar system.
 
#21 ·
Quote:
Originally Posted by jsc1973 View Post

Based on that definition, which some have suggested, Pluto-Charon is a double planet (or double dwarf planet), but Earth-Moon is not. What you read is true. The barycenter of the Pluto-Charon system is outside of either body. The only other known objects in the solar system which have such a relationship are Jupiter and the Sun itself, and that only because of Jupiter's great distance from the Sun.

The reason I wouldn't advocate that definition of a double planet is based on that fact. In the future, when the Moon moves farther away from Earth, the barycenter will move outside the Earth and therefore "qualify" the Earth-Moon system under that definition. The only reason that it's below the surface of Earth at the present time is because the Moon is so ridiculously close to Earth, relatively speaking. There are no other solar system bodies where this is true; the movement of the secondary to create such a barycenter in any other case would result in the escape of the secondary body.

Back in the 1960s, Isaac Asimov offered a definition where any system where a primary and secondary body share the same orbit, and the solar attraction of the secondary is higher than that of the primary, it's a double planet. That qualifies the Earth-Moon system (0.46 ratio), but not Pluto-Charon. There are some dual asteroids by this definition, and some insignificant Jovian and Neptunian moons as well, but none of those objects are in hydrostatic equilibrium, and would therefore be disqualified as planets on that count.

The common sense resolution of this would be to say that any two bodies that qualify on either or both counts are a dual system, which would mean that both systems in question will always be dual (dwarf) planets at any time in the past, present, or future. In both cases, the secondary body is so large compared to the primary that you have to say that both Earth-Moon and Pluto-Charon are special cases. Neither system could exist if they were not defined by a different relationship than every other major satellite of a primary in the solar system.
Your arguments are making me think that the Moon should be considered a planet.
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Have you ever read Asimov's fiction, especially the Foundation series? His books make the claim (unsubstantiated, of course) that our solar system is unique for having a double planet (he meant Earth, as Charon had not yet been discovered) and for having a planet with massive rings.

I still think that Pluto should not be considered a planet based on its inability to clear its orbital neighbourhood. Here's a quote from http://en.wikipedia.org/wiki/Clearing_the_neighbourhood
Quote:
A large body which meets the other criteria for a planet but has not cleared its neighbourhood is classified as a dwarf planet. This includes Pluto, which shares its orbital neighbourhood with Kuiper belt objects such as the plutinos. The IAU's definition does not attach specific numbers or equations to this term, but all the planets have cleared their neighbourhoods to a much greater extent than any dwarf planet, or any candidate for dwarf planet.
...
Over many orbital cycles, a large body will tend to cause small bodies either to accrete with it, or to be disturbed to another orbit, or to be captured either as a satellite or into a resonant orbit. As a consequence it does not then share its orbital region with other bodies of significant size, except for its own satellites, or other bodies governed by its own gravitational influence. This latter restriction excludes objects whose orbits may cross but that will never collide with each other due to orbital resonance, such as Jupiter and its trojans, Earth and 3753 Cruithne, or Neptune and the plutinos.
Now, the failure to attach specific numbers or equations should probably be remedied by the IAU, but the fact stands that Pluto simply does not have the gravitational ability to be a cow catcher. This article accounts for Cruithne and comets too.

I'm not trying to be arrogant, I'm just getting into one of my favourite subjects.
 
#22 ·
No doubt the images released to the public that show extra terrestrial civilisation will be photo-shopped out.
 
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