Don't worry about it. These giants are big, but not necessarily massive enough to go supernova at the end of their lives.
Besides, hypothetically, even if it were to explode like a supernova, it won't affect us much. Here is the number:
d = distance to the closest giant (5200light-yr)
E = total energy arising from supernova (1e51erg or something like that)
The energy receied at the Earth is
E / (4 *pi *d*d).
Now compare this number with the energy we receive every second from the Sun:
E_sun / (4 * pi * r*r)
where r is the distance between the Earth and the Sun (1.5e13 cm). You do the math, then the ratio of these two quantities comes out to be:
[E/(4*pi*d*d)] / [E_sun/(4*pi*r*r)] ~ 2.4
So all we get from this supernova is about 2 seconds worth of energy received from the Sun. And I'll tell you that the actual energy received from the supernova is much, much smaller.
You're missing my point (and being modded up...sigh).
In an ideal world where everything falls as 1-D numerical grid, that may work. But there are n-body rotating around the object plus Saturn, making it difficult gravitationally to achieve what you hypothesize. If what you're saying is true, there are other cases where a similar geographical feature is observed. That's my argument based on statistical occurrence. I know it's weak but that's all I've got at this point. And IAAA but never really cared about planets.
It's easy to concoct a "model" that is not easy to verify. You can believe in it, but that ain't science.
And someone said "a satellite can have a satellite": yes. but having a ring is a whole different story. You have to think how to create a stable gravitational field to keep the ring to form first, and then destroy it later. Easy said, hard to do.
Tidal lock doesn't necessarily mean that the revolution of Iapetus is in the plane of the ring or Saturn's rotation (or is it so? I can't locate its ephemeris).
Besides this object is so small that it is more likely to be part of Saturn's ring. Its gravitation field is not significant enough to trap a larger number of small bodies as Saturn does. And if you're saying that Saturn's ring particles gets deposited there, then that's probably not right either. As they decend onto the surface, it'd make a crater, not mountains. I'm pretty sure the differential velocity is large enough to do that.
So sorry, I'm not buying this yet. Give me some numbers and I'll happily listen, though.
The presence of Saturn itself would disrupt the formation of a ring around a small planetary body like a satellite, I would think. Not that I have done n-body simulation for this type of things.
If not, then I'd bet the gravitational perturbation alone would increase perpendicular motion of this hypothetical ring in the plane of rotation (i.e., the ring would get puffed up).
In any case, I'd look for geophysical reasons before invoking some "ring" theory.
This guy is using a guidance system to track siderial motion, pal. From what I recall in Hally's comet, the plate scale used in the image is pretty small and in 2 minutes exposure the trace of stars with the siderial motion is much greater than it appears in the photograph.
I doubt that wind is the culprit. Like you say, it'd be relatively low frequency oscillation if true (unless this photo was taken with a cheaper mount...Meade produces a solid mount, btw). Often I saw this type of vibration got picked up by a tripod from the ground vibration (jumping up and down, or a car driving by). Or a simple bump in a telescope produces a high-freq, but slow decaying oscillation, too.
The light of a meteor originates from super-heated plasma that forms in front of a meteor, as it drags through air at a high speed. It is not a part of a meteor body itself that is glowing and spinning as it run across the sky.
Besides, these meteors (that disintegrates) are very small (less than an inch). I doubt that we would see any significant sign of spinning if it is so small (the oscillation amplitude of the contrail can imply the scale size of a meteor, which must be huge if it is indeed a spinning rock shown in the photo).
The killer evidence, to me, is that the direction of blur shown in the field stars is aligned with the motion of the wobbly contrail of the meteor. Its oscillatory amplitude declines as it passes, also. That may be a signature of vibration dumping in the support mount of the camera.
I've read a part of Camille Flammarion before. He's an interesting observer (and a very literate one at that). But I won't take his drawing in his book as always accurate.
Off topic but...Comet Macholz is found right by Pleiades ("seven" star cluster) tonight. I could manage to spot it with a pair of binocular in Boston. It's fairly fuzzy and faint, though.
At some point, the Chinese won't be able to lower their wages any longer. Also at the same time, the Japanese automater will have invested into highly mechanised division that pays off its overhead in a relatively short time.
And I would not be surprised if Japanese automakers are looking into building a cheaper, pure electronic vehicle in assembly line. If so, the deployment of full roboic assembly line allows them to compete with cheap Chinese labor.
That said, I don't think this is about the decline of the population in the manufacture business; it's about making a long-term plan (10 - 20 years) for future.
What exactly does this robotic mission promise to accomplish?
I don't mean to be negative (if they can, great!), but it is not exactly an easy job to unscrew bolts and fastners by hand, even on ground!
I forgot what is built in as a modular unit without many mechanical parts to support. Solar panel and batteries may be replaceable with care. But can someone tell me if a gryoscope can be replaced without using Philip screwdriver? I know that some science instruments are fastened with bolts. I'm not holding my breath that $154M robotic mission can replace the STIS or install the COS for the Hubble.
Anyway, if they can fix the Hubble, great. I'd even call that the replacement of solar panels, batteries, and gryoscopes would receive a "successful" tag.
Wow, you ask very nicely. You like her, don't you?:-)
Actually there are little difference between astronomers and astrophysicists any more. But some of us call ourselves "astrophysicists" since we tend to pay more attention to physics than doing cataloguing or mere statistical analysis of some star/galaxy distribution.
But no matter. Like I said, there is little difference. We'll treat her just like as we are.
Ask astronomers again in a couple of months if they all agree if the morphology of planetary nebulae is solved by the magnetic field alone.
It's cool that they had done POLARIMETRIC measurement of these objects (that's far more dead than UV spectroscopy), however. Especially there is a star like Eta Carinae which seems to have a weaker magnetic field and its bi-polar structure is being driven by its stellar wind alone.
FUSE is not dead yet. It sucks to operate with a single inertial torquer, but it's far from dead. A Good thing is that it has been operating with the coarse mode for a long time, and it probably continue to do so with one good wheel. So as long as it goes after point-like sources, it should still be useful.
Or so I hope. FUSE had never achieved its maximum operational capacity; but it might as well hang on with the little that it got. A tough figher.
Note to those regular folks: The GALEX is primarily an UV imaging mission (pictures), whereas the FUSE is an UV spectroscopic mission (gathering ultra-violet spectra of stars and galaxies).
Slashdot Mirror
I wonder what the good folks down in White Sand have to say about this...they may be ticked off by having too much visibility in the area.
[A rocket launch may scare the shit out of cows!]
Supernovae are quite faint in X-rays (until their blast waves hit circum/inter-stellar material).
Not all of the energy emerge in the form of light, either.
If I had a mod point, I'd give you "+1 insightful."
-IAAA (though I was trained to be a carpenter...)
Well, that may not be true, either, according to the article I read about a decade ago:
/. What have I done?
ApJ article (1993): Our Sun III
Oh gosh, I referenced ApJ in
Don't worry about it. These giants are big, but not necessarily massive enough to go supernova at the end of their lives.
Besides, hypothetically, even if it were to explode like a supernova, it won't affect us much. Here is the number:
d = distance to the closest giant (5200light-yr)
E = total energy arising from supernova (1e51erg or something like that)
The energy receied at the Earth is
E / (4 *pi *d*d).
Now compare this number with the energy we receive every second from the Sun:
E_sun / (4 * pi * r*r)
where r is the distance between the Earth and the Sun (1.5e13 cm). You do the math, then the ratio of these two quantities comes out to be:
[E/(4*pi*d*d)] / [E_sun/(4*pi*r*r)] ~ 2.4
So all we get from this supernova is about 2 seconds worth of energy received from the Sun. And I'll tell you that the actual energy received from the supernova is much, much smaller.
El Nino effect causes oscillatory changes of a few milli-seconds in the Earth's rotation (I believe it has to do with the sea level near the equator).
I bet you didn't notice that, did you? If not, then, don't worry about it.
You're missing my point (and being modded up...sigh).
In an ideal world where everything falls as 1-D numerical grid, that may work. But there are n-body rotating around the object plus Saturn, making it difficult gravitationally to achieve what you hypothesize. If what you're saying is true, there are other cases where a similar geographical feature is observed. That's my argument based on statistical occurrence. I know it's weak but that's all I've got at this point. And IAAA but never really cared about planets.
It's easy to concoct a "model" that is not easy to verify. You can believe in it, but that ain't science.
And someone said "a satellite can have a satellite": yes. but having a ring is a whole different story. You have to think how to create a stable gravitational field to keep the ring to form first, and then destroy it later. Easy said, hard to do.
Of course, I hoped that I could've spelt "rejoice" correctly.
[This one is gonna get attention of nerds as well as spelling nazi's.]
Tidal lock doesn't necessarily mean that the revolution of Iapetus is in the plane of the ring or Saturn's rotation (or is it so? I can't locate its ephemeris).
Besides this object is so small that it is more likely to be part of Saturn's ring. Its gravitation field is not significant enough to trap a larger number of small bodies as Saturn does. And if you're saying that Saturn's ring particles gets deposited there, then that's probably not right either. As they decend onto the surface, it'd make a crater, not mountains. I'm pretty sure the differential velocity is large enough to do that.
So sorry, I'm not buying this yet. Give me some numbers and I'll happily listen, though.
The presence of Saturn itself would disrupt the formation of a ring around a small planetary body like a satellite, I would think. Not that I have done n-body simulation for this type of things.
If not, then I'd bet the gravitational perturbation alone would increase perpendicular motion of this hypothetical ring in the plane of rotation (i.e., the ring would get puffed up).
In any case, I'd look for geophysical reasons before invoking some "ring" theory.
Oh my, thousands of nerds will come out and rejoyce over this pic.
Screw science tag; it's Star Wars, baby!
[Literally, I expect to see little scientific discourse on this thread...so sad.]
This guy is using a guidance system to track siderial motion, pal. From what I recall in Hally's comet, the plate scale used in the image is pretty small and in 2 minutes exposure the trace of stars with the siderial motion is much greater than it appears in the photograph.
I doubt that wind is the culprit. Like you say, it'd be relatively low frequency oscillation if true (unless this photo was taken with a cheaper mount...Meade produces a solid mount, btw). Often I saw this type of vibration got picked up by a tripod from the ground vibration (jumping up and down, or a car driving by). Or a simple bump in a telescope produces a high-freq, but slow decaying oscillation, too.
Gene, your explanation is unlikely.
The light of a meteor originates from super-heated plasma that forms in front of a meteor, as it drags through air at a high speed. It is not a part of a meteor body itself that is glowing and spinning as it run across the sky.
Besides, these meteors (that disintegrates) are very small (less than an inch). I doubt that we would see any significant sign of spinning if it is so small (the oscillation amplitude of the contrail can imply the scale size of a meteor, which must be huge if it is indeed a spinning rock shown in the photo).
The killer evidence, to me, is that the direction of blur shown in the field stars is aligned with the motion of the wobbly contrail of the meteor. Its oscillatory amplitude declines as it passes, also. That may be a signature of vibration dumping in the support mount of the camera.
I've read a part of Camille Flammarion before. He's an interesting observer (and a very literate one at that). But I won't take his drawing in his book as always accurate.
Off topic but...Comet Macholz is found right by Pleiades ("seven" star cluster) tonight. I could manage to spot it with a pair of binocular in Boston. It's fairly fuzzy and faint, though.
At some point, the Chinese won't be able to lower their wages any longer. Also at the same time, the Japanese automater will have invested into highly mechanised division that pays off its overhead in a relatively short time. And I would not be surprised if Japanese automakers are looking into building a cheaper, pure electronic vehicle in assembly line. If so, the deployment of full roboic assembly line allows them to compete with cheap Chinese labor. That said, I don't think this is about the decline of the population in the manufacture business; it's about making a long-term plan (10 - 20 years) for future.
No. But a supply of WD-40 is included as fringe benefit.
What exactly does this robotic mission promise to accomplish?
I don't mean to be negative (if they can, great!), but it is not exactly an easy job to unscrew bolts and fastners by hand, even on ground!
I forgot what is built in as a modular unit without many mechanical parts to support. Solar panel and batteries may be replaceable with care. But can someone tell me if a gryoscope can be replaced without using Philip screwdriver? I know that some science instruments are fastened with bolts. I'm not holding my breath that $154M robotic mission can replace the STIS or install the COS for the Hubble.
Anyway, if they can fix the Hubble, great. I'd even call that the replacement of solar panels, batteries, and gryoscopes would receive a "successful" tag.
If you replace "scientist" with "priest", or more accurately, "Roman Catholic" priest, your statement is fairly accurate...
I'm gonna go to hell, ain't I?
Wow, you ask very nicely. You like her, don't you? :-)
Actually there are little difference between astronomers and astrophysicists any more. But some of us call ourselves "astrophysicists" since we tend to pay more attention to physics than doing cataloguing or mere statistical analysis of some star/galaxy distribution.
But no matter. Like I said, there is little difference. We'll treat her just like as we are.
Moderate up all the posts above.
It's about angular momentum and it's a hotly debated field of study in astronomy (not much in astrophysics).
Ask astronomers again in a couple of months if they all agree if the morphology of planetary nebulae is solved by the magnetic field alone.
It's cool that they had done POLARIMETRIC measurement of these objects (that's far more dead than UV spectroscopy), however. Especially there is a star like Eta Carinae which seems to have a weaker magnetic field and its bi-polar structure is being driven by its stellar wind alone.
FUSE is not dead yet. It sucks to operate with a single inertial torquer, but it's far from dead. A Good thing is that it has been operating with the coarse mode for a long time, and it probably continue to do so with one good wheel. So as long as it goes after point-like sources, it should still be useful.
Or so I hope. FUSE had never achieved its maximum operational capacity; but it might as well hang on with the little that it got. A tough figher.
At this point there are about seven comments (and mostly with would-be "funny" tags).
This situation represents the level of public interest in UV spectroscopy:
Not very much.
It's a pretty sad day to be an UV astronomer.
Note to those regular folks: The GALEX is primarily an UV imaging mission (pictures), whereas the FUSE is an UV spectroscopic mission (gathering ultra-violet spectra of stars and galaxies).