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Remembering Pioneer 10
Daniel Goldman writes "Twenty one years ago today, Pioneer 10 became the first spacecraft to leave our solar system, by crossing the orbit of Neptune (which was then the farthest planet from the Sun). Pioneer 10 was the first spacecraft to enter the asteroid belt, the ring of giant rocks beyond Mars. It survived and zoomed on to Jupiter in late 1973, where it became the first spacecraft to take close-up photographs of the storms on the giant planet's surface. After Jupiter, it kept going, collecting data on the particles and radiation it encountered. More info about Pioneer 10 at Wikipedia."
...when it returns as V'Ger. ;)
I believe that was a Voyager probe, not a Pioneer probe.
No, they meant that Pluto has an eccentric orbit, which crosses the orbit of Neptune. Between 1979 and 1999, Pluto was the 8th planet from the sun, and Neptune the 9th.
The edge of the solar system is the heliopause. Pioneer 10 has not gotten close to that. The honor of the first man-made object to leave the solar system belongs to Voyager 1, launched over 25 years ago.
as i understand it the Oort cloud stretches half way to the next star.
that would take some time..
For those looking for a more in depth study of the pioneer missions to the outer planets, this book published in the late 70's (now fully online) is truly a hidden gem from NASA's site. It details every last design aspect of the spacecraft in extremely high detail. We've certianly come a long way in ~30 years from grainy washed out Pioneer photopolarimeter images to super high resolution ultrasharp CCD images from Cassini.
- "Hear that?! The percolations are imminent! Cease your ingress!"
... first spacecraft to enter the asteroid belt, the ring of giant rocks beyond Mars. It survived ...
Contrary to nearly every science fiction chase scene, the asteroid belt in orbit around our star is hardly what anyone would call dense. It "survived"? Heck, it'd have to try pretty hard to hit a rock out there!
According to the article, they define the edge of the solar system as the heliopause.
Pioneer was supposed to die after reaching the outer planets, but it died in late 2003.
Pioneer 10 is not really dead, it is just so far away we can no longer hear it.
A real quick and dirty gives me about 12,000 miles/second. A pretty good clip, but not yet really boogying. Give it another five years before you have to worry about the intergalactic traffic cops handing out a ticket.
Assuming the dust mote doesn't get it first.
KFG
Regardless of how you define it, the farthest planet from the sun has not changed in the last 21 years.
Putting aside the debate over the 10th planet, the farthest planet does in fact change over time. There are times when Neptune is the farthest planet from the Sun, and there are other times when Pluto is the farthest planet from the Sun. So in fact the farthest planet from the Sun HAS CHANGED in the last 21 years.
Why this is the case is left as an excercise for the reader...
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www.moneybythenumbers.com
Differing eccentricities.
There was recently a conference about thee er/]
Pioneer Anomaly and the conference webpage
has links to various attempts of explanation.
[http://www.zarm.uni-bremen.de/Pion
As far as I know, there is no consensus if the
anomaly has a trivial explanation
(gas leaking from satellite, dust in the
solar system etc.) or if something non-trivial is happening, such as a quantum garvity effect,
dark matter etc.
No, red shift is only indirectly related to distance from source. What matters is the velocity of the source when the light left relative to our velocity now. Red shift occurs when the source was moving away from us. It's similar to the zeeeouuuu sound cars make when they drive past you - when they are going away, they sound lower pitched.
Given this, and the observation that more distant objects tend to be more red-shifted (to which you refer), we conclude that "the universe is expanding."
> Hi - why can't NASA try to use some nearer spacecratt
> (Cassini, Mars Express etc.) to communicate with Pioneer 10?
Because they really aren't that much closer, nor do they have sifficiently good antennas or receivers for the frequencies used for Pioneer 10 downlink.
I would have to do some research, but I think the previous post referring to inadequate D/L signal strength as the cause of loss of communications is incorrect. I believe the prevailing theory is that the Radioisotope Thermal Generator (RTG ) used as a power supply can no longer provide enough power to trun on the transmitter. Once they miss a few passes, the pointing drifts off, then you are shafted.
Nope. Remember Sedna?
Not that Sedna's that big a deal. A lot of astronomers don't consider Pluto to be a true planet either...
"If we let things terrify us, life will not be worth living."
- Seneca
No, it's more like an address. Basically, the lines represent the period of a bunch of different pulsars and their distance from our sun. The idea is that if E.T. happens to know three (I think) or more of these pulsars, and happens to read binary, he might go "aha!" and find us and steal our water and/or women.
The spin-flip transition has a wavelength of 21cm. Next to the people is the binary number 8, 8x21=168cm, the approximate height of a human. Also this can be used to make sure the scale is correct, because Pioneer is show to scale behind the humans.
The period of the spin-flip transition is around 1420(Mhz)^-1. The off burst pattern is actually a map of the Sol system's location in relation to 14 pulsars, whose periods are compaired to that of molecular hydrogen's transition by way of binary. By knowing this the recieving society is supposed to look in the sky and find some of the pulsars with those frequencies and be able to locate us.
Pretty nifty use of math and science I think, but perhaps including an example of binary counting would have been a good idea. I forget what the binary near the planets signifies, either distance or mass, I can't recall which. Probably distance, because that diagram is not to scale.
If you go to the Pioneer site, it talks about uplinking commands to Pioneer via 200Kw transmitter....I think most space probes don't have that kind of reserve. Of course in addition there are issues with the antenna gain of them, as well as communicating with the same standard, etc. Its really just a lot easier to put low powered transmitters and smaller antenna on the bird, and just make up for it with on the earth side.
The Hubble expansion will indeed red-shift light from very distant objects. However, it is a large-scale effect observable in very distant objects (other galaxies) but not in gravitationally bound systems like out own galaxy or the solar system.
The velocity with which a distant galaxy is receeding from us is proportional to its distance - ie the further away the faster it receeds. The baloon analogy works, but for a more 3-D effect I prefer to to think of raisins inside a loaf as it rises. The more dough there is rising between raisins the faster the expansion (I think I nicked that from Stephen Hawking).
Intellectual Property
Intellectual: of the mind
Property: that over which one has control
It's also possible that the emission of the cathode
of the pencil tube used in the transmitter has
fallen off to the point where the tube doesn't generate a usefull signal anymore. And the spacecraft doesn't have a spare tube.
That tube has been going longer than most tv picture tubes.
Actually, at that time, it passed both, so they're both right. Some people may not know that pluto's orbit is not centred around the sun, but offset, so that it occaisionally crosses inside neptune's orbit.
Mouse, Mice. Goose, Geese. Moose... Moose?
Mercury is not iffy! The Messenger Spacecraft is on track for an August launch this year.
$#!^ happens, but why does it always have to happen to me???