Posts Tagged ‘magnetosphere’
For the first time, astronomers have snapped photos of auroras lighting up Uranus’s icy atmosphere.
Two fleeting, Earth-size auroral storms were imaged by the Hubble Space Telescope as they flared up on the dayside of the gas giant in November 2011.
“The last time we had any definite signals of auroral activity on Uranus was when NASA’s Voyager 2 probe swung by in 1986,” said study leader Laurent Lamy, an astronomer at the Observatoire de Paris in Meudon, France.
“But this is the first time we can actually see these emissions light up with an Earth-based telescope.”
Auroras are light displays often seen at the highest latitudes of Earth, Jupiter, and Saturn—all of which all have magnetospheres that act as shields against incoming solar storms…
The team timed their Hubble observations specifically to coincide with the solar storm, and about six weeks later, Hubble spotted the auroras flaring up in Uranus’s upper atmosphere…
The auroras’ unusual appearance might have something to do with the planet’s oddball orientation.
Unlike the other seven planets, Uranus’s magnetic axis is 60 degrees off from its spin axis. In addition, spin axis itself has a bizarre 98-degree tilt relative to the solar system’s orbital plane. In other words, the planet seems to roll around on its side as it orbits the sun.
Uranus’s auroras are very short-lived, and Lamy speculates that’s because of the difference between the orientation of the incoming solar particles and the planet’s unusual magnetic field.
Delightful stuff. We’re fortunate that [so far] the rising tide of anti-scientific drivel that consumes nutballs — and politicians seeking the nutball vote — hasn’t affected astronomy.
I wouldn’t be surprised to hear some Tea Party hack ask that the Hubble conduct a search for angels.
UCLA atmospheric scientists have discovered a previously unknown basic mode of energy transfer from the solar wind to the Earth’s magnetosphere. The research, federally funded by the National Science Foundation, could improve the safety and reliability of spacecraft that operate in the upper atmosphere.
“It’s like something else is heating the atmosphere besides the sun. This discovery is like finding it got hotter when the sun went down,” said Larry Lyons, UCLA professor of atmospheric and oceanic sciences and a co-author of the research, which is in press in two companion papers in the Journal of Geophysical Research.
The sun, in addition to emitting radiation, emits a stream of ionized particles called the solar wind that affects the Earth and other planets in the solar system. The solar wind, which carries the particles from the sun’s magnetic field, known as the interplanetary magnetic field, takes about three or four days to reach the Earth. When the charged electrical particles approach the Earth, they carve out a highly magnetized region — the magnetosphere — which surrounds and protects the Earth…
The rate at which the solar wind transfers energy to the magnetosphere can vary widely, but what determines the rate of energy transfer is unclear.
“We thought it was known, but we came up with a major surprise,” said Lyons, who conducted the research with Heejeong Kim…
RTFA. Slowly. Carefully.
Demanding concepts, critically important to a great deal of what we may plan to do in the space around this wee planet of ours.
Artist’s conception of a FTE
During the time it takes you to read this article, something will happen high overhead that until recently many scientists didn’t believe in. A magnetic portal will open, linking Earth to the sun 93 million miles away. Tons of high-energy particles may flow through the opening before it closes again, around the time you reach the end of the page.
“It’s called a flux transfer event or ‘FTE,’” says space physicist David Sibeck of the Goddard Space Flight Center. “Ten years ago I was pretty sure they didn’t exist, but now the evidence is incontrovertible…”
Researchers have long known that the Earth and sun must be connected. Earth’s magnetosphere (the magnetic bubble that surrounds our planet) is filled with particles from the sun that arrive via the solar wind and penetrate the planet’s magnetic defenses. They enter by following magnetic field lines that can be traced from terra firma all the way back to the sun’s atmosphere.
“We used to think the connection was permanent and that solar wind could trickle into the near-Earth environment anytime the wind was active,” says Sibeck. “We were wrong. The connections are not steady at all. They are often brief, bursty and very dynamic…”
There are many unanswered questions: Why do the portals form every 8 minutes? How do magnetic fields inside the cylinder twist and coil? “We’re doing some heavy thinking about this…” says Sibeck.
Meanwhile, high above your head, a new portal is opening, connecting your planet to the sun.
Stunning and provocative. Read the article and other suggested materials at the NASA site.