Space Weather

[sanbie]

Oh my giddy aunt!...don't like the sound of this at all...20th here tomorrow!

[thelufias]

STRONG X2-CLASS SOLAR FLARE (UPDATED): New sunspot AR3229 erupted on Feb. 17th (2016 UT), producing a strong X2.2-class solar flare. NASA's Solar Dynamics Observatory (SDO) recorded the extreme ultraviolet pulse:



Radiation from the flare ionized the top of Earth's atmosphere, causing a deep shortwave radio blackout over the Americas. Mariners, aviators and ham radio operators may have noticed loss of signal and other unusual propagation efftects at frequencies below 30 MHz for more than an hour after the flare.

The long-duration flare also launched a solar tsunami. It is the shadowy shock wave in this 193 angstrom movie from SDO:



The US Air Force has reported a Type II solar radio burst coming from the tsunami. The drift rate of the burst suggests a shock speed greater than 2400 km/s (5.4 million mph). Solar tsunamis and Type II radio bursts are closely linked to CMEs, and we should expect to see one soon emerging from the blast site.

Update: The CME has emerged, and it has an Earth-directed component. ETA: Feb. 20th. Geomagnetic storms ranging from category G1 (Minor) to G3 (Strong) are possible after the CME arrives.

[thelufias]

A LARGE COMET IS STREAKING TOWARD THE SUN: Comet 96P/Machholz is streaking toward the sun for a close encounter inside the orbit of Mercury. Coronagraphs onboard the Solar and Heliospheric Observatory (SOHO) are monitoring its approach.

This is no ordinary comet flyby. Most comets that fall toward the sun are small (~10 meters) and rapidly evaporate; SOHO has seen thousands of these doomed sungrazers. Comet 96P is different. Measuring 6 kilometers across, it is big enough to survive close proximity to the sun. Perihelion (closest approach to the sun) on Feb. 7th is only 0.12 AU away.

Some researchers think 96P might be an Alien. Chemically, it is unlike other comets in the Solar System, lacking normal amounts of carbon and cyanogen. It also has a strangely-tilted orbit that takes it very close to the sun. Two orbits ago, unexpected fragments appeared ahead of the comet; researchers aren't sure how they were produced.

"96P is a very atypical comet, both in composition and in behavior, so we never know exactly what we might see," says Karl Battams of the Naval Research Lab in Washington DC. "Accordingly, we're running a special observing program with SOHO to maximize the science return, so the normal flow of public coronagraph data will be slowed for a few days (to six images/hour). Hopefully we can get some beautiful science out of this and share with everyone as soon as we can."

"By the way," adds Battams, "this comet is named for Don Machholz, who was an extraordinary ground-based 'amateur' astronomer, and also an extremely great guy. He passed away unexpectedly last year, so there's some poignancy to this passage of his 'premier' comet discovery--he made many."

[thelufias]

NIGHT SPIRAL' OVER HAWAII: On Wednesday night, Jan. 18th, a luminous spiral spun across the night sky. It was photographed by the "Subaru-Asahi Star Camera" on Mauna Kea:



It looks like a giant galaxy. In fact, it came from SpaceX. Earlier the same day, a Falcon 9 rocket launched from Cape Canaveral carrying a US Space Force GPS satellite (GPS 3 SV-06). The spiral was the aftermath.

"Space X spirals" are becoming commonplace over the Pacific where Falcon 9 rocket stages are often deorbitted. They are created by plumes of unused fuel venting from the rocket's spinning second stage before they plunge into the ocean.

[sanbie]

Look at that...Australia is smack bang in the middle...no wonder our weather is up the wahoozy!

[Jherrith]

X-CLASS SOLAR FLARE: Sunspot AR3182 is living up to the hype. Fully visible for less than 24 hours, the active sunspot has already produced an intense X1.2-class solar flare. NASA's Solar Dynamics Observatory recorded the eruption on Jan. 6th just before 0100 UT:



The explosion inflated a dome of glowing-hot plasma, which hovered above the blast site for more than an hour. This may have contained the debris. So far no coronal mass ejection (CME) has been observed emerging from the area.

A pulse of X-rays and extreme UV radiation from the flare ionized the top of Earth's atmosphere, causing a shortwave radio blackout across South Pacific:



Ham radio operators, mariners and aviators may have noticed unusual propagation effects at frequencies below 30 MHz for as much as an hour after the flare.

[thelufias]

SIGNIFICANT FARSIDE SOLAR EXPLOSION: Something just exploded on the farside of the sun. SOHO watched the debris--a very bright and fast CME--billow away from the sun's southeastern limb on Jan. 3rd:

It won't hit Earth. NOAA analysts have modeled the CME and determined that the edge of the storm cloud will narrowly miss our planet a few days from now.

NASA's Solar Dynamics Observatory detected shock waves from the blast wrapping around both of the sun's poles. This suggests a very powerful explosion--possibly an X-flare. Radiation from the flare was eclipsed by the edge of the sun, reducing its intensity by one to two orders of magnitude, so that Earth-orbiting satellites detected only a C4-class event.

Whatever exploded will soon turn to face Earth. Helioseismic echoes pinpoint its location no more than 2 days behind the sun's eastern limb.

[thelufias]

Dec. 3, 2003: Earth is surrounded by a magnetic force field--a bubble in space called "the magnetosphere" tens of thousands of miles wide. Although many people don't know it exists, the magnetosphere is familiar. It's a far flung part of the same planetary magnetic field that deflects compass needles here on Earth's surface. And it's important. The magnetosphere acts as a shield that protects us from solar storms.

According to new observations, however, from NASA's IMAGE spacecraft and the joint NASA/European Space Agency Cluster satellites, immense cracks sometimes develop in Earth's magnetosphere and remain open for hours. This allows the solar wind to gush through and power stormy space weather.



Above: An artist's rendition of NASA's IMAGE satellite flying through a 'crack' in Earth's magnetic field. [more]

"We've discovered that our magnetic shield is drafty, like a house with a window stuck open during a storm," says Harald Frey of the University of California, Berkeley, lead author of a paper on this research published Dec. 4 in Nature. "The house deflects most of the storm, but the couch is ruined. Similarly, our magnetic shield takes the brunt of space storms, but some energy slips through its cracks, sometimes enough to cause problems with satellites, radio communication, and power systems."
"The new knowledge that the cracks are open for long periods can be incorporated into our space weather forecasting computer models to more accurately predict how our space weather is influenced by violent events on the Sun," adds Tai Phan, also of UC Berkeley, co-author of the Nature paper.
The solar wind is a fast-moving stream of electrically charged particles (electrons and ions) blown constantly from the Sun. The wind can get gusty during violent solar events, like coronal mass ejections (CMEs), which can shoot a billion tons of electrified gas into space at millions of miles per hour.

Earth's magnetosphere generally does a good job of deflecting the particles and snarled magnetic fields carried by CMEs. Even so, space storms and their vivid effects, like auroras which light up the sky over the polar regions with more than a hundred million watts of power, have long indicated that the shield was not impenetrable.

In 1961, Jim Dungey of the Imperial College, United Kingdom, predicted that cracks might form in the magnetic shield when the solar wind contained a magnetic field that was oriented in the opposite direction to a portion of the Earth's field. In these regions, the two magnetic fields would interconnect through a process known as "magnetic reconnection," forming a crack in the shield through which the electrically charged particles of the solar wind could flow.



An artist's rendition of magnetic reconnection. The amber-brown lines denote lines of magnetic force. The bright spot is where oppositely-directed fields are making contact and "reconnecting."

In 1979, Goetz Paschmann of the Max Planck Institute for Extraterrestrial Physics in Germany detected the cracks using the International Sun Earth Explorer (ISEE) spacecraft. However, since this spacecraft only briefly passed through the cracks during its orbit, it was unknown if the cracks were temporary features or if they were stable for long periods.

In the new observations, the Imager for Magnetopause to Aurora Global Exploration (IMAGE) satellite revealed an area almost the size of California in the arctic upper atmosphere where a 75-megawatt "proton aurora" flared for hours. A proton aurora is a form of Northern Lights caused by heavy solar ions striking Earth's upper atmosphere, causing it to emit ultraviolet light--invisible to the human eye but detectable by the Far Ultraviolet Imager on IMAGE. While this aurora was being recorded by IMAGE, the 4-satellite Cluster constellation flew far above IMAGE, directly through the crack, and detected solar wind ions streaming through it.

Below: An artist's rendition of the four Cluster satellites near a stream of solar ions pouring in through a crack in the magnetosphere. [more]



see caption
This stream of solar wind ions bombarded our atmosphere in precisely the same region where IMAGE saw the proton aurora. The fact that IMAGE was able to view the proton aurora for more than 9 hours implies that the crack remained continuously open. Researchers estimate that the crack was twice the size of Earth at the boundary of our magnetic shield--about 38,000 miles (60,000 km) above the planet's surface. Since the magnetic field converges as it enters the Earth in the polar regions, the crack narrowed to about the size of California down near the upper atmosphere.


Fortunately, these cracks don't expose Earth's surface to the solar wind. Our atmosphere protects us, even when our magnetic field doesn't. The effects of solar storms are felt mainly in the high upper atmosphere and the region of space around Earth where satellites orbit.

Stay tuned later this week for a follow-up story from Science@NASA about how magnetic cracks have lately sparked beautiful auroras--a phenomenon of the upper atmosphere--in some unexpected places.

[thelufias]

And of course we have snow in the forecast....

[Jherrith]

MUST-SEE! LUNAR OCCULTATION OF MARS: Tomorrow night, Dec. 7-8, the full Moon will pass in front of Mars, producing a beautiful occultation across much of North America and Europe. This movie, created by graphic artist Larry Koehn, shows what observers can expect to see:



Movie credit: Larry Koehn of Shadowandsubstance.com

This is a great time for an occultation because Mars is within a week of its closest approach to Earth. The Red Planet's disk is unusually wide (more than 17 arcseconds across). Even modest backyard telescopes can reveal details on the Martian surface partially eclipsed by lunar mountains and crater rims.

This is also a naked-eye event. Because of its proximity to Earth, Mars is now brighter than every star in the sky (twice as bright as Sirius). Its piercing red glow will be visible even next to the glaring edge of the full Moon