That's easily explained. The ripples appear for material that has just passed near the moon. Material inward of the moon's position orbits faster than the moon, so the ripples there appear ahead of the moon's orbit. Material outside moves slower, so the ripples appear behind the moon.
People have already more or less addressed this, but I'll speak up anyway.
They DO send color cameras into space. After a fashion. You have surely seen the color images taken by Cassini's ISS instrument already, so you know that it is possible. To do this, they put various filters in place and expose the CCD to take the image. The colors are then combined (with extreme love and care to get accurate color, in many cases) to make a color image. However, this clearly takes at least three times the exposure time that a single black and white image through a clear filter does. (Actually, more than that. Each filter blocks a lot of the light, so you tend to expose for longer than you would for a simple clear filter in order to get your signal to noise down.) So for a lot of science, when color isn't expected to be very important anyway (like for discovering a moon), you just use the clear filter.
You nailed it. The ring material inside the S/2005 S1's position is moving faster than the moon, so the waves that the moon excites appear ahead of the moon's present position. (That material just had a close encounter.) The other edge of the gap is orbiting more slowly, so the moon PASSES it, so the waves appear behind the moon.
I'd avoid the word "turning" because it suggests a solid object. The rings are anything but solid.
There are other ways to make asymmetries in these wakes. If the moon isn't well-centered in the gap (although it isn't clear why it wouldn't be) or has a significant orbital eccentricity, you'll get asymmetry as well.
Bear in mind that Saturnian moons are named for Titans or Titan-like gods from other mythologies. So while I'm sure people can generate a lot of sweet names, if you really want to play the game by the rules, that's a key one.
No good. That name would be for a moon of Jupiter (as they're usually named for his various lovers). Saturnian moons are named for Titans or Titan-like gods from other pantheons.
Because Titan is in a class by itself in the Saturnian system. Titan is the only large moon there, so the rules are expected to be generally rather different.
It's not that hard at all. You just speed it up a bit and let it use an inside track. When you get close, you hit the brakes and it moves away from the Sun a bit.
No reason it would crash into the Sun. In fact, *that* is a terribly difficult thing to get to happen. The angular momentum/energy change needed for that is huge.
Depending on how frugal you are with fuel, this can take a while. But it isn't all that hard.
Actually, there was a pole shift. It just shifted to *exactly* the same place, so no one noticed. Right? Riiiiiight.
Seriously, the other giant planets might not be good reflectors for this purpose. Consider how dim Uranus is in the visible wavelengths, for example. It'll probably be worse in x-rays. There may only be a few options. (Venus would be my next candidate.)
Obviously you could do that. But you don't get a lot of improvement in data quality by getting closer to the Sun (it's pretty well-resolved from here) and it's more expensive. Which is why I suggested one in the same orbit, not because that was the only option.
This is only helpful for half of the time. The other half, Jupiter would be reflecting parts of the Sun that we can see because we're on the same side.
If monitoring the far side of the Sun (Don't you just *want* to say "dark side"?) really becomes important, we'd need a spacecraft in the same orbit as Earth, but on the opposite side of the Sun.
Aye, and we say "Jovian" rather than "Jupiterian". The English languge is a chimeral beast. Sometimes, it's best to smile and nod and not worry about it too much.
Actually, the Sun is only called "Sol" in science fiction, in my experience. Astronomers (and I am one) call it "the Sun", with capital letters, usually. Similarly, the Moon is our big orbiting body, "a moon" is a natural satellite in general. It's just a case of the specific name being used to describe other things in a similar class.
(You can find other cases of this: "T Tauri stars", "hot Jupiters", "plutinos", etc.)
In addition to what others have said, Saturn has another fun problem with locating moons: some of them are embedded in the ring system. The rings are bright. It's hard to see a small moon in there, unless you get close up and can resolve the gaps the moons clear out (and the moons within them). Or you could wait for a ring-plane crossing, but that's still not a sure-fire method.
Also, it should be noted that people only started doing CCD-based searches about 7 or 8 years ago. It's sort of a case where astronomers got whizzo new technology, and then forgot that there were things close to home to look for because we'd stopped looking years ago. (Poor telescopes, film, and what with having spacecraft fly by... is it entirely shocking that people didn't think to do telescopic surveys?)
As far as I can see from the article and from the IAU website, the International Astronomical Union hasn't approved these names. By common agreement in the astronomical community, they have the final word on approving names. So until they meet and approve this, all that is being reported is that the Cassini team is *suggesting* names for the moons *to* the IAU. The IAU has the right to shoot down their suggestins. (I'm a bit skeptical of Polydeuces being accepted since it doesn't fit the usual scheme. But what do I know?)
In the end, the International Astronomical Union. Which has not approved these names, as far as I can see. Until they do, it's just the Cassini team suggesting things.
Saturnian moons are named for Titans or Titan-like gods, not Trojan War characters. It's not clear to me that this name will actually be accepted by the IAU, but we'll see. (I don't see that the IAU has actually accepted the names, so the headline is a rather misleading.)
You end up librating about the triangular trojan points, provided the mass ratio between the planet and moon (or Sun and planet) is large enough. So you don't exactly sit in a stationary sense, but the L4 and L5 points are stable.
You can either prove this with a little calculus or just look up. There are clusters of asteroids in Jupiter's trojan points (that's where the name comes from, in fact). They've almsot certainly been there for millions, probably billions, of years. It seems likely that they're stable.
That's not true, for starters. There are a lot of other names. Uranian moons are named for sprites on Pope or Shakespeare works. Saturnian moons already are starting on Nordic and other pantheons. Anyone paying attention to the recent discoveries in the Edgeworth-Kuiper Belt has seen American Indian names crop up. Asteroids are named for people, for the most part.
In the case of planetary moons and surface features, rules are followed about the nomeclature to make it easier to figure out what belongs where. Saturnian moons are named for Titans or other old gods in other cultures. Jovian moons are named for paramours of Zeus (although I think that we might be running out, suprising although that is). Surface features on Venus are named for women and/or female gods. Mercury's fatures are named for artists. Etc.
We're not restricting outselves to the Greco-Roman world, but there is a method to the madness.
No, for a sufficently large mass ratio (greater than about 30:1) and provided you're not creating a resonance in the libration frequencies, they are stable by the usual meaning of the term in physics.
Actually, it's frequently thought that you should be able to sputter a large fraction of a planet's atmosphere with solar wind bombardment. Whether that is really up to the challege of stripping Mars's atmosphere is another question.
You're talking about two different things. Aligning the iron atoms is ferromagnetism. It does NOT lead to changes in the pole direction. And it is not what generates the fields of the planets (or the Sun).
What we have is a dynamo with convection and spin and whole lotta feedbacks that amply fields. While the exact details are still murky (it's a tough field to understand as the feedbacks are a bitch), we're fairly certain that that is what causes fields on planets and stars.
The mini-comet theory isn't very widely accepted at all. The data Frank cites is generally held to be cosmic ray hits on the detector, for example. (They're single-pixel detections.) If the mini-comet theory were producing significant enough amounts of oxygen to change the chemistry of Earth's atmosphere, it would do the same elsewhere. But Earth has the only atmosphere with signifcant amounts of molecular oxygen. Which makes sense if you realized that the oxygen we have is the by-product of photosynthesis.
I believe that Venus, Mars, the giant planets, Pluto, and Titan all have reducing atmospheres. In other words, every body that isn't Earth. (And which has a significant atmosphere in the first place.)
Spinning isn't the issue. It didn't stop spinning, for one thing. It did, however, solidify. Which makes it impossible to maintain the planetary dynamo. But this has nothing to do with stopping the spin. (It's an important distinction. Stopping the spin takes quite a bit of work, since the planet is still spinning. Cooling leads to solidifying, though. On all bodies, including, eventually, Earth.)
Whether or not the lack of a field allowed enough atmospheric sputtering from the solar wind to remove almost an entire atmosphere is the subject of considerable debate. (The cooling also would shut off the resupplying mechanism for the atmosphere, which complicates the issue, of course.)
We should be especially worried at this news, since we're killing coral at an alarming rate. If the coral has mitigated warming in the past, there's less of it to help now.
Presumably, you would scramble the letters across items in the picture from iteration to iteration. That would certainly make things much more complicated for any automated system, even with human help to crack it. Also, you can exploit the point-of-view changes (even slight ones) to make it more difficult for a computer to determine which image is which. So even with a good database of what part of the image maps to which phrase, you can make it fairly tough, I think.
Which isn't to say that no-one is up to this challenge. I'd be surprised if such a system lasted a full year before being cracked. But I suppose that drives technology forward, so it's not an all-bad thing.:-)
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That's easily explained. The ripples appear for material that has just passed near the moon. Material inward of the moon's position orbits faster than the moon, so the ripples there appear ahead of the moon's orbit. Material outside moves slower, so the ripples appear behind the moon.
It's all about Kepler's third law.
People have already more or less addressed this, but I'll speak up anyway.
They DO send color cameras into space. After a fashion. You have surely seen the color images taken by Cassini's ISS instrument already, so you know that it is possible. To do this, they put various filters in place and expose the CCD to take the image. The colors are then combined (with extreme love and care to get accurate color, in many cases) to make a color image. However, this clearly takes at least three times the exposure time that a single black and white image through a clear filter does. (Actually, more than that. Each filter blocks a lot of the light, so you tend to expose for longer than you would for a simple clear filter in order to get your signal to noise down.) So for a lot of science, when color isn't expected to be very important anyway (like for discovering a moon), you just use the clear filter.
You nailed it. The ring material inside the S/2005 S1's position is moving faster than the moon, so the waves that the moon excites appear ahead of the moon's present position. (That material just had a close encounter.) The other edge of the gap is orbiting more slowly, so the moon PASSES it, so the waves appear behind the moon.
I'd avoid the word "turning" because it suggests a solid object. The rings are anything but solid.
There are other ways to make asymmetries in these wakes. If the moon isn't well-centered in the gap (although it isn't clear why it wouldn't be) or has a significant orbital eccentricity, you'll get asymmetry as well.
Bear in mind that Saturnian moons are named for Titans or Titan-like gods from other mythologies. So while I'm sure people can generate a lot of sweet names, if you really want to play the game by the rules, that's a key one.
No good. That name would be for a moon of Jupiter (as they're usually named for his various lovers). Saturnian moons are named for Titans or Titan-like gods from other pantheons.
Because Titan is in a class by itself in the Saturnian system. Titan is the only large moon there, so the rules are expected to be generally rather different.
It's not that hard at all. You just speed it up a bit and let it use an inside track. When you get close, you hit the brakes and it moves away from the Sun a bit.
No reason it would crash into the Sun. In fact, *that* is a terribly difficult thing to get to happen. The angular momentum/energy change needed for that is huge.
Depending on how frugal you are with fuel, this can take a while. But it isn't all that hard.
Actually, there was a pole shift. It just shifted to *exactly* the same place, so no one noticed. Right? Riiiiiight.
Seriously, the other giant planets might not be good reflectors for this purpose. Consider how dim Uranus is in the visible wavelengths, for example. It'll probably be worse in x-rays. There may only be a few options. (Venus would be my next candidate.)
Obviously you could do that. But you don't get a lot of improvement in data quality by getting closer to the Sun (it's pretty well-resolved from here) and it's more expensive. Which is why I suggested one in the same orbit, not because that was the only option.
This is only helpful for half of the time. The other half, Jupiter would be reflecting parts of the Sun that we can see because we're on the same side.
If monitoring the far side of the Sun (Don't you just *want* to say "dark side"?) really becomes important, we'd need a spacecraft in the same orbit as Earth, but on the opposite side of the Sun.
Aye, and we say "Jovian" rather than "Jupiterian". The English languge is a chimeral beast. Sometimes, it's best to smile and nod and not worry about it too much.
Actually, the Sun is only called "Sol" in science fiction, in my experience. Astronomers (and I am one) call it "the Sun", with capital letters, usually. Similarly, the Moon is our big orbiting body, "a moon" is a natural satellite in general. It's just a case of the specific name being used to describe other things in a similar class.
(You can find other cases of this: "T Tauri stars", "hot Jupiters", "plutinos", etc.)
In addition to what others have said, Saturn has another fun problem with locating moons: some of them are embedded in the ring system. The rings are bright. It's hard to see a small moon in there, unless you get close up and can resolve the gaps the moons clear out (and the moons within them). Or you could wait for a ring-plane crossing, but that's still not a sure-fire method.
Also, it should be noted that people only started doing CCD-based searches about 7 or 8 years ago. It's sort of a case where astronomers got whizzo new technology, and then forgot that there were things close to home to look for because we'd stopped looking years ago. (Poor telescopes, film, and what with having spacecraft fly by... is it entirely shocking that people didn't think to do telescopic surveys?)
As far as I can see from the article and from the IAU website, the International Astronomical Union hasn't approved these names. By common agreement in the astronomical community, they have the final word on approving names. So until they meet and approve this, all that is being reported is that the Cassini team is *suggesting* names for the moons *to* the IAU. The IAU has the right to shoot down their suggestins. (I'm a bit skeptical of Polydeuces being accepted since it doesn't fit the usual scheme. But what do I know?)
In the end, the International Astronomical Union. Which has not approved these names, as far as I can see. Until they do, it's just the Cassini team suggesting things.
Saturnian moons are named for Titans or Titan-like gods, not Trojan War characters. It's not clear to me that this name will actually be accepted by the IAU, but we'll see. (I don't see that the IAU has actually accepted the names, so the headline is a rather misleading.)
You end up librating about the triangular trojan points, provided the mass ratio between the planet and moon (or Sun and planet) is large enough. So you don't exactly sit in a stationary sense, but the L4 and L5 points are stable.
You can either prove this with a little calculus or just look up. There are clusters of asteroids in Jupiter's trojan points (that's where the name comes from, in fact). They've almsot certainly been there for millions, probably billions, of years. It seems likely that they're stable.
That's not true, for starters. There are a lot of other names. Uranian moons are named for sprites on Pope or Shakespeare works. Saturnian moons already are starting on Nordic and other pantheons. Anyone paying attention to the recent discoveries in the Edgeworth-Kuiper Belt has seen American Indian names crop up. Asteroids are named for people, for the most part.
In the case of planetary moons and surface features, rules are followed about the nomeclature to make it easier to figure out what belongs where. Saturnian moons are named for Titans or other old gods in other cultures. Jovian moons are named for paramours of Zeus (although I think that we might be running out, suprising although that is). Surface features on Venus are named for women and/or female gods. Mercury's fatures are named for artists. Etc.
We're not restricting outselves to the Greco-Roman world, but there is a method to the madness.
No, for a sufficently large mass ratio (greater than about 30:1) and provided you're not creating a resonance in the libration frequencies, they are stable by the usual meaning of the term in physics.
Actually, it's frequently thought that you should be able to sputter a large fraction of a planet's atmosphere with solar wind bombardment. Whether that is really up to the challege of stripping Mars's atmosphere is another question.
You're talking about two different things. Aligning the iron atoms is ferromagnetism. It does NOT lead to changes in the pole direction. And it is not what generates the fields of the planets (or the Sun).
What we have is a dynamo with convection and spin and whole lotta feedbacks that amply fields. While the exact details are still murky (it's a tough field to understand as the feedbacks are a bitch), we're fairly certain that that is what causes fields on planets and stars.
The mini-comet theory isn't very widely accepted at all. The data Frank cites is generally held to be cosmic ray hits on the detector, for example. (They're single-pixel detections.) If the mini-comet theory were producing significant enough amounts of oxygen to change the chemistry of Earth's atmosphere, it would do the same elsewhere. But Earth has the only atmosphere with signifcant amounts of molecular oxygen. Which makes sense if you realized that the oxygen we have is the by-product of photosynthesis.
I believe that Venus, Mars, the giant planets, Pluto, and Titan all have reducing atmospheres. In other words, every body that isn't Earth. (And which has a significant atmosphere in the first place.)
Spinning isn't the issue. It didn't stop spinning, for one thing. It did, however, solidify. Which makes it impossible to maintain the planetary dynamo. But this has nothing to do with stopping the spin. (It's an important distinction. Stopping the spin takes quite a bit of work, since the planet is still spinning. Cooling leads to solidifying, though. On all bodies, including, eventually, Earth.)
Whether or not the lack of a field allowed enough atmospheric sputtering from the solar wind to remove almost an entire atmosphere is the subject of considerable debate. (The cooling also would shut off the resupplying mechanism for the atmosphere, which complicates the issue, of course.)
We should be especially worried at this news, since we're killing coral at an alarming rate. If the coral has mitigated warming in the past, there's less of it to help now.
Presumably, you would scramble the letters across items in the picture from iteration to iteration. That would certainly make things much more complicated for any automated system, even with human help to crack it. Also, you can exploit the point-of-view changes (even slight ones) to make it more difficult for a computer to determine which image is which. So even with a good database of what part of the image maps to which phrase, you can make it fairly tough, I think.
:-)
Which isn't to say that no-one is up to this challenge. I'd be surprised if such a system lasted a full year before being cracked. But I suppose that drives technology forward, so it's not an all-bad thing.