Other Space News

This forum is for discussing space science topics related to Stardust@home.

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Re: Other Space News

Post by fjgiie » Thu Oct 11, 2012 4:46 am

Evelyn, it's funny that you ask when Voyager I will leave the solar system and enter interstellar space. I mean, what is funny is that you ask now.

The interstellar particles are hitting Voyager's sensors at a higher rate and solar particles have fallen off sharply. The only other criteria left for moving to interstellar space is the direction of the solar systems magnetic field. That is being evaluated now.

To me Voyager I is already in interstellar space but an announcement should be made in months, not 2015 as approximated earlier.     (We're going to Beaufort today 49 miles away nearly out of the country into international waters)

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Re: Other Space News

Post by SmithES » Thu Oct 11, 2012 7:54 am

John (jsmaje), Thank you for the NATURE website. I appreciate Fred's reply (fjgiie) as well. The google sites were ambiguous in their answers to my question, with mixed opinions from astrophysists, ranging from "No, Voyager 1 hasn't exited our Solar System" to "Yes, it has." The reason I ask NOW, is that I have been following Voyager 1 since its launch in Sept. 1977, and I have followed its progress through our Solar System since. (I still have the tape shown on BBC-Nova in 1991 So, I am almost "intimately acquainted" with Voyager and its visits to our planets.) Since earlier this year, when "hype" first entered the Internet, I have waited for Voyager 1's final goodbye.
John, The article in NATURE has details I've not found other places. Therefore, I will excerpt it for others who might not be aware.

"NATURE: Voyager's long goodbye"
"In the latest twist in the story, the craft seems to be traversing an unexpected ‘dead zone’. This week, Robert Decker, a space scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, and his colleagues report1 in Nature that at Voyager 1’s current location . . . 18.2 billion kilometres from the Sun, the average velocity of solar particles has dropped to nearly zero. Decker’s team first reported the change last year, when it had measurements of the particles’ velocity only in the radial direction, outwards from the Sun. At the time, the team thought that the change was a sign that the craft was nearing the heliopause, where solar particles are expected to collide with powerful winds generated by supernovae that exploded some 5 million to 10 million years ago. The collision would force the solar particles to stop moving outwards and push them sideways, like a stream of water hitting a solid surface. To test the idea, engineers commanded Voyager 1 to roll on its side seven times, so that its instruments could record particle velocities along a line perpendicular to its course. Given that sending a command to Voyager 1 now takes 17 hours, and that the spacecraft’s transmitter runs at 23 watts — about as powerful as a refrigerator light bulb — such communication is a feat in itself. The researchers were astonished to find that the particles had zero velocity in this polar direction, too — indicating that they were almost stationary rather than being buffeted by stellar winds. That cannot happen at the heliopause, says Decker. “We therefore conclude … that Voyager 1 is not at the present time close to the heliopause, at least in the form that it has been envisioned,” the team writes. In an article in press in The Astrophysical Journal, they propose that Voyager 1 is in a region where magnetic field lines running through the outer heliosphere link up with the magnetic field of the rest of the Galaxy. Here the field would create a conduit for galactic cosmic rays, causing the spikes in detection. Cosmic rays accelerated within the heliosphere would tend to move along other field lines and be less likely to get to Voyager. If this model is correct, say McComas and Schwadron, the heliopause may still be years away . . . There no longer exists any guidance on what constitutes getting out of the Solar System.”
Evelyn (ERSTRS, SmithES, DOM)

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Re: Other Space News

Post by caprarom » Fri Oct 12, 2012 5:05 am

John, Fred & Evelyn, I very much appreciate the info. Thanks for sharing. I really like Evelyn's husband, Ted's, take on the situation. Of course, I'm partial to the instincts of a fellow ChE.

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Re: Other Space News

Post by SmithES » Sat Oct 13, 2012 6:23 am

Mike, John and Fred, During the past 35 years as Voyager 1 traversed our Solar System, that "little feller" has sent back a myriad of astounding and even unbelievable images. One quite beautiful photo of the Prometheus geyser erupting on IO has seared itself into my mind---and my heart, forever. Oliver Wendell Holmes said, "A mind that is stretched by a new experience can never go back to its old dimensions." Voyager 1, has stretched my mind . . . I can never go back. . . .

1979 fly by: Prometheus geyser erupts on IO (#1- actual photograph. #2 Artist's rendition of geyser)
Prometheus geyser.png
Prometheus geyser.png (11.93 KiB) Viewed 3151 times
Io geyser, Voyager 1 1979 fly by.jpg
Io geyser, Voyager 1 1979 fly by.jpg (58.84 KiB) Viewed 3151 times

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Re: Other Space News

Post by jsmaje » Mon Jan 20, 2014 1:22 pm

Congratulations to the Rosetta team today (20th Jan 2014) on a successful crucial stage in this ambitious and already 10-year-long space venture:

http://www.esa.int/Our_Activities/Space ... ibernation

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