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 Post subject: Re: Space Is Deep
PostPosted: Wed Nov 06, 2019 9:30 am 
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NASA Confirms Voyager 2 Has Left the Solar System
By Ryan Whitwam on November 5, 2019 at 1:26 pm

https://www.extremetech.com/extreme/301515-nasa-confirms-voyager-2-has-left-the-solar-system

Humanity first left the solar system in 2012 when the Voyager 1 probe passed into interstellar space decades after leaving the planets behind. Now, there’s a second spacecraft beyond the limits of our solar system: Voyager 2. Luckily, Voyager 2’s instruments are in somewhat better shape than Voyager 1’s, so scientists were able to observe the transition from the heliosphere, which is dominated by the sun, to the interstellar medium (ISM).

Both Voyager probes launched in 1977, with Voyager 2 heading into space a few weeks before Voyager 1. The two probes are physically identical, but they took different paths through the solar system. They took advantage of the “Grand Tour,” an alignment of the planets that occurs only once every 175 years. Voyager 1 visited and got gravity assists from Jupiter and Saturn before heading off toward the edge of the solar system. Voyager 2 swung past Jupter, Saturn, Neptune, and Uranus. It made its last planetary observation of Uranus in 1989, almost a decade after Voyager 1 had started its long march toward the edge of the solar system.

When Voyager 1 reached the edge of our solar system, known as the heliopause, it no longer had a functional plasma spectrometer. As a result, there was some debate about when, exactly, the probe left our solar system. So, we missed the expected transition from warm solar plasma to the denser cold plasma of the ISM. Eventually, measurements of local electrons and magnetic field shifts confirmed it was in interstellar space.

Voyager 2 has just sent back data proving that it has also crossed the heliopause, and it had a fully functional plasma spectrometer. The transition happened about a year ago in November 2018, and the changeover was roughly in-line with what scientists expected based on Voyager 1’s indirect readings. As Voyager 2 crossed from the heliosphere to the ISM, it detected a 20-fold increase in plasma density.

Voyager 1 and 2 crossed the heliopause at roughly the same distance from the sun, 121.6 AU and 119 AU, respectively. However, their exit points were about 150 AU apart. Scientists are studying the discrepancies in the data in hopes of gaining a better understanding of the boundary between our solar system and the wider galaxy. For example, Voyager 2 detected a continuous change in magnetic field directions as it crossed into the ISM, whereas Voyager 1 did not. Voyager 2 has also continued to see low-energy particles from the sun in the ISM, but Voyager 1 didn’t.

It will be some time before we have more data to study. The only functional probe that has any hope of reaching the heliopause is New Horizons, which is currently flying through the Kuiper Belt. It could leave the solar system around 2040, but we don’t know if it will maintain communication with Earth that long.


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 Post subject: Re: Space Is Deep
PostPosted: Wed Nov 06, 2019 7:02 pm 
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The last transmission was...

"...oh shit, I left the stove on...."

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Ummmm, you guys know it has a plutonium power source and you're all fucked...

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 Post subject: Re: Space Is Deep
PostPosted: Tue Nov 12, 2019 8:06 am 
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 Post subject: Re: Space Is Deep
PostPosted: Wed Nov 27, 2019 4:34 pm 
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Out There

In Praise of Lumpy Gravy From the Cosmic Kitchen

Without that texture, there’d be none of us.


Dennis Overbye

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As Thanksgiving approaches, would-be chefs and hosts, including apparently my editors, are perfecting their techniques for making the all-important gravy for the turkey and potatoes.

I have my moments as a cook — come over for my stardust waffles some Sunday morning — but I have never had the patience or skill to master gravy, so it usually comes out lumpy. This is a problem at the dinner table. On the grandest possible scale, however, lumps are a good thing.

During the Big Bang 14 billion years ago, a fizzy stew of energy and gas emerged that became, and still suffuses, the universe. Astronomers initially thought this cosmic gravy was perfectly uniform, like something Julia Child might have whipped up. But not even Einstein’s “Old One” can make a perfect gravy, apparently, and in 1992 astronomers discovered that the cosmic gravy is, like mine, lumpy. And that’s a reason to be thankful this year, or any year, because without those lumps there would be no us.

“If you’re religious, it’s like seeing God,” George Smoot, an astronomer at the University of California’s Lawrence Berkeley National Laboratory who won a Nobel Prize for the 1992 discovery, said at the time.
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That fizzy energy stew of the Big Bang manifests itself today as a bath of microwave radiation that fills the sky. In effect, we live amid the fading remnant of the primordial fireball; astronomers call it the cosmic microwave background.

This cosmic gravy has been the subject of three Nobel Prizes: one to Arno Penzias and Robert Wilson, the Bell Labs astronomers who discovered the radiation by accident back in 1964; one to Dr. Smoot and his collaborator, John Mather, in 2006, and the third to James Peebles of Princeton, for his early work on the properties of this fireball.

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 Post subject: Re: Space Is Deep
PostPosted: Wed Dec 04, 2019 7:17 am 
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Hoag's Object Is a Galaxy Within a Galaxy Within a Galaxy (and Nobody Knows Why)
By Brandon Specktor 3 hours ago Science & Astronomy

https://www.space.com/hoags-object-perfect-ring-mystery.html

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With a perfectly symmetrical ring circling a red sphere of stars, Hoag's object is one of the prettiest mysteries in the universe. (Image credit: NASA/ESA, Processing: Benoit Blanco)

Look closely at the serpent constellation slithering through the northern sky, and you might see a galaxy within a galaxy within a galaxy.

This cosmic turducken is known as Hoag's object, and it has befuddled stargazers since astronomer Arthur Hoag discovered it in 1950.

The object in question is a rare, ring-shaped galaxy measuring some 100,000 light-years across (slightly larger than the Milky Way) and located 600 million light-years from Earth. In a recent image of the oddball object taken by the Hubble Space Telescope and processed by geophysicist Benoit Blanco, a bright ring of billions of blue stars forms a perfect circle around a much smaller and denser sphere of reddish stars. In the dark gap between the two stellar circles, another ring galaxy — much, much farther away from us — peeks out to say hello.

What's going on here, and what tore Hoag's object in two? Astronomers still aren't sure; ring galaxies account for less than 0.1% of all known galaxies, and so they aren't the easiest objects to study. Hoag himself suggested that the galaxy's peculiar ring formation was merely an optical illusion caused by gravitational lensing (an effect that occurs when extremely high-mass objects bend and magnify light). Later studies with better telescopes disproved this idea.

Another popular hypothesis suggests that Hoag's object was once a more common, disk-shaped galaxy but an ancient collision with a neighboring galaxy ripped a hole through the disk's belly and permanently warped its gravitational pull. If such a collision occurred in the last 3 billion years, then astronomers looking through radio telescopes should have been able to see some of the fallout from the accident. No such evidence has been found.

If there was a cosmic crash at the core of Hoag's object, it must have happened so long ago that all the evidence has been swept away. With only a handful of other known ring galaxies available to study (none of which shows the perfectly symmetrical characteristics found in this one), Hoag's object remains a mystery wrapped in a riddle inside an enigma — you know, like a turducken.


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 Post subject: Re: Space Is Deep
PostPosted: Mon Dec 09, 2019 9:48 am 
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Dave Whamond
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