Tag: solar wind

New Horizons confirms solar wind slows at greater solar distances

9:57 am

The New Horizons science team today released data that confirms that, as theorized, the speed of the solar wind decreases as it travels farther from the Sun.

As the solar wind moves farther from the Sun, it encounters an increasing amount of material from interstellar space. When interstellar material is ionized, the solar wind picks up the material and, researchers theorized, slows and heats in response. SWAP [an instrument on New Horizons] has now detected and confirmed this predicted effect.

The SWAP team compared the New Horizons solar wind speed measurements from 21 to 42 astronomical units to the speeds at 1 AU from both the Advanced Composition Explorer (ACE) and Solar TErrestrial RElations Observatory (STEREO) spacecraft. (One AU is equal to the distance between the Sun and Earth.) By 21 AU, it appeared that SWAP could be detecting the slowing of the solar wind in response to picking up interstellar material. However, when New Horizons traveled beyond Pluto, between 33 and 42 AU, the solar wind measured 6-7% slower than at the 1 AU distance, confirming the effect.

The data also suggests that New Horizons could exit the heliosphere and enter interstellar space as early as sometime in the 2020s.

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DSCOVR in safe mode

9:25 am

The solar wind monitoring satellite DSCOVR has gone into safe mode.

It is at present unclear what the problem is, or whether they can recover the spacecraft.

DSCOVR’s history is packed with political shenanigans. It was first proposed by Gore as Triana, with its only purpose to take global pictures of the Earth so Gore and the left could use these images for environmental propaganda. Bush canceled it, partly because it really had no legitimate scientific purpose and partly to prevent the left this propaganda tool. It was resurrected during the Obama administration but with a more useful purpose, providing early solar wind data so that Earth-based power grids could get prepared should a major solar storm be incoming. NASA’s other solar wind monitors ACE and SOHO, were already decades beyond their planned lifespan, and the space agency, the solar weather community, and especially the world’s electrical power industry, was desperate to get a new satellite in space.

Ironically, with DSCOVR’s shutdown we are still dependent on ACE and SOHO. Nor is there any replacement satellite anywhere close to launch.

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Pluto’s solar wind interaction more like a planet’s

9:11 am

Data from New Horizons has found that Pluto, in its interaction with the solar wind, behaves more like a planet than a comet.

Previously, most researchers thought that Pluto was characterized more like a comet, which has a large region of gentle slowing of the solar wind, as opposed to the abrupt diversion solar wind encounters at a planet like Mars or Venus. Instead, like a car that’s part gas- and part battery-powered, Pluto is a hybrid, the researchers say. “This is an intermediate interaction, a completely new type. It’s not comet-like, and it’s not planet-like. It’s in-between,” McComas said. “We’ve now visited all nine of the classical planets and examined all their solar wind interactions, and we’ve never seen anything like this.”

…Pluto continues to confound. Since it’s so far from the sun – an average of about 5.9 billion kilometers (3.7 billion miles) – and because it’s so small, scientists thought Pluto’s gravity would not be strong enough to hold heavy ions in its extended atmosphere. But, “Pluto’s gravity clearly is enough to keep material sufficiently confined,” McComas said. Further, the scientists found that very little of Pluto’s atmosphere is comprised of neutral particles converted to electrically charged ions and swept out into space.

As I’ve written previously, we simply don’t know enough yet about planets to come up with a reasonable definition. As far as I’m concerned, Pluto will remain a planet until we do.

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Scientists have found the source of the water on the Moon and Mercury: the solar wind.

8:48 am

Scientists have found the source of the water on the Moon and Mercury: the solar wind. Key paragraph:

“We found that the ‘water’ component, the hydroxyl, in the lunar regolith is mostly from solar wind implantation of protons, which locally combined with oxygen to form hydroxyls that moved into the interior of glasses by impact melting,” said Zhang, the James R. O’Neil Collegiate Professor of Geological Sciences. “Lunar regolith is everywhere on the lunar surface, and glasses make up about half of lunar regolith. So our work shows that the ‘water’ component, the hydroxyl, is widespread in lunar materials, although not in the form of ice or liquid water that can easily be used in a future manned lunar base.” [emphasis mine]

Though this result would explain the detection of hydrogen on the lunar surface and would also mean that this hydrogen is far less useful for future colonists than previously hoped, it doesn’t eliminate the possibility that there is ice in the permanently shadowed craters near the lunar poles that came from other as yet unknown sources.

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When a solar storm slammed into both the Earth and Mars in January 2008, scientists were able to directly measure the importance of the Earth’s magnetic field in protecting our atmosphere from oxygen loss.

9:22 am

When a solar storm slammed into both the Earth and Mars in January 2008, scientists were able to directly measure the importance of the Earth’s magnetic field in protecting our atmosphere from oxygen loss.

They found that while the pressure of the solar wind increased at each planet by similar amounts, the increase in the rate of loss of martian oxygen was ten times that of Earth’s increase. Such a difference would have a dramatic impact over billions of years, leading to large losses of the martian atmosphere, perhaps explaining or at least contributing to its current tenuous state. The result proves the efficacy of Earth’s magnetic field in deflecting the solar wind and protecting our atmosphere.

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Voyager 1 at the edge

10:31 am

This week the American Geophysical Union (AGU) is having its annual fall meeting in San Francisco. Due to the wonders of technology, they are now making their press conferences available to reporters on line. Thus, I will be posting periodic updates after each conference. This will allow my readers to get a heads up on stories they will be seeing in the mainstream press in the next few hours.

Right now they are wrapping up a press conference from the team of the Voyager 1 spacecraft, in which they have described the spacecraft’s status.
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