Voyager 1 Exits Our Solar System 341
eldavojohn writes "The first man-made craft to do so is now entering a 'cosmic purgatory' between solar systems and entering an interstellar space of the Milky Way Galaxy. With much anticipation, Voyager 1 is now 'in a stagnation region in the outermost layer of the bubble around our solar system. Voyager is showing that what is outside is pushing back.' After three decades the spacecraft is still operating and apparently has enough power and fuel to continue to do so until 2020. The first big piece of news? 'We've been using the flow of energetic charged particles at Voyager 1 as a kind of wind sock to estimate the solar wind velocity. We've found that the wind speeds are low in this region and gust erratically. For the first time, the wind even blows back at us. We are evidently traveling in completely new territory. Scientists had suggested previously that there might be a stagnation layer, but we weren't sure it existed until now.' This process could take months to years to completely leave the outer shell but already scientists are receiving valuable information."
Moving goalposts (Score:3, Informative)
This news again? (Score:5, Informative)
It's really really cool that Voyager is still going, but this talk of crossing into the heliosheath, etc seems to be dragged out a bit (yes, it's a vague and slow transition, I understand...)
http://science.slashdot.org/story/05/05/24/2334240/voyager-1-crosses-the-termination-shock [slashdot.org]
http://science.slashdot.org/story/11/12/02/0243246/voyager-probes-give-us-ets-view [slashdot.org]
http://science.slashdot.org/story/10/12/14/1451216/voyager-1-beyond-solar-wind [slashdot.org]
http://science.slashdot.org/story/11/04/28/2314203/voyager-set-to-enter-interstellar-space [slashdot.org]
Re:Amazing (Score:5, Informative)
Voyagers transmitter uses a pencil type vacuum tube in the final amplifier. At the time they were designed there were no transistors that could operate at the required frequency and power level and also withstand the expected cosmic radiation in space. Tubes were the ONLY devices RAD hard enough to do the job.
Since then RCA has quit making tubes (and a lot of other stuff as well).
Re:Moving goalposts (Score:5, Informative)
The Oort cloud, if it proves to exist, is speculated to extend quite a ways out -- possibly 2/3 of the way to the nearest star by some estimations. It's a much looser "full shell" of relatively stationary objects, where the Kuiper belt is more similar to a large asteroid belt.
Wikipedia has some good visualizations and links --
http://en.wikipedia.org/wiki/Oort_cloud [wikipedia.org] http://en.wikipedia.org/wiki/Kuiper_belt [wikipedia.org] http://en.wikipedia.org/wiki/Heliosphere [wikipedia.org]
Re:11 Billion (Score:2, Informative)
"Space is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space, listen..." -HHGTG
Re:11 Billion (Score:5, Informative)
I wish they would send some more of these (Score:3, Informative)
With updated equipment, high resolution sensors/ cameras.... heck even put on a hubble like telescope while we're at it... a dozen of these in all directions.... that would definitely kick ass... >
Communications numbers (Score:5, Informative)
The amazing thing (well, one of the amazing things) about the Voyager program is the communication link. Voyager's signal, as received on Earth, is almost unbelievably weak.
One can use the Friis Transmission Equation [wikipedia.org] to see just how weak the signal from Voyager 1 is at the moment:
Pr = Pt * Gt * Gr * (lambda/(4 * pi * R))^2, where
Pr is received power, in watts;
Pt is transmitted power, in watts;
Gt is the gain of the transmitting antenna, relative to an isotropic source (a unit-less value);
Gr is the gain of the receiving antenna (one of the 70m DSN antennas), relative to an isotropic source (a unit-less value);
lambda is the operating wavelength, in meters, and equal to c/f, or very close to 300/fM, where fM is the operating frequency in MHz;
and R is the range (distance) in meters.
Pt = 18 watts [nasa.gov] (assuming this hasn't degraded over time and distance);
Gt = 48 dBi [nasa.gov], or about 63100;
Gr = 74 dBi [nasa.gov], or about 25.1*10^6;
fM = 8420 MHz [nasa.gov], so lambda = 300/fM = 0.0356 meters; and
R = 17,545,000,000 km [nasa.gov], or 1.75 * 10^13 meters.
Grinding all this out, one is left with a received signal strength -- at the terminals of a 70-meter dish, mind you -- of:
Pr = 18 * 63100 * 25.1*10^6 * (0.0356/(4 * pi * 1.75 * 10^13))^2 = 7.45 * 10^(-19) watts, or 745 -- wait for it -- zeptowatts [wikipedia.org].
This is equal to -181.3 dBW, or -151.3 dBm. (I don't know how many Libraries of Congress that is.)
In the year 2020, when the probe's power generator is expected to expire, the probe will be about 2 * 10^13 meters away from Earth; using the same calculation the signal will have weakened slightly, to 5.73 * 10^(-19) watts, or 573 zeptowatts, -182.4 dBW, or -152.4 dBm.
(Unless I've made some trivial calculation error, of course.)
Re:I wonder... (Score:5, Informative)
Voyager are not the only ones.
Pioneer 10 and 11 were both launched with sufficient velocity to escape the solar system. They were launched before Voyager, but did not have as large a velocity, so were passed by the Voyager probes in the 1990s as the furthest from the Earth.
I'm pretty sure this was planned, since the Pioneer probes has this really cool plaque on them (designed by Carl Sagan), in the event they were found by alien species:
http://en.wikipedia.org/wiki/Pioneer_plaque [wikipedia.org]
Re:This is what happens when Americans make things (Score:5, Informative)
While that's true for many types of things, ABC News has been doing a Made in America series for most of this year. (I've only seen a few of the reports when reaired on World News Now.) They've found lots of things made in America, and some was cheaper than the foreign made stuff. I don't remember all of the examples, but toys, furniture, cooking implements were some of them. (The most recent report I saw was a followup where the Bundt pan factory hired a few more people, at least partially because sales had gone way up since the last report.)
As others have said in past discussions of this type, what do you call a Toyota made (assembled/built) in Kentucky? Is that an American car or a foreign car?
I disagree with your main premise, but if you want "American made", you can find it, at least for many things.. but you'll sometimes have to pay more, and definitely will have to look harder.
Re:Moving goalposts (Score:5, Informative)
Voyager will define where the edge is. Or rather, returns enough data so we can decide where it is.
Really, it's past what was thought of as the edge of the solar system when it was built.
Re:This is what happens when Americans make things (Score:5, Informative)
Re:Consumers, not businessmen, killed US made good (Score:2, Informative)
Re:Amazing (Score:4, Informative)
This level of quality exists for almost anything you would care to buy. These items costs a bit more and they don't carry them at Walmart, but that doesn't mean they don't exist.
Congratulations, you've just discovered the Sam Vimes' Boots theory of wealth [lspace.org].
TL;DR: Only the rich can afford to save money.
Re:Worse (Score:4, Informative)
You've clearly never seen a proper cheap CRT. Yes, compared to bottom-of-the-barrel TN TFTs they would still have been better when new but with ten years and some age-induced blurring on them even a cheap TN panel will be easier on the eyes.
Of course, I've been using IPS monitors for years (and CRTs are a pain, you need a vertical refresh rate of at least 75 Hz for them to be usable and even then there are all sorts of other issues which are not cancelled out by "It's got blacker blacks than a TFT!!11one").