Spotless Days Current Stretch: 0 days 2016 total: 0 days (0%) 2015 total: 0 days (0%) 2014 total: 1 day (<1%) 2013 total: 0 days (0%) 2012 total: 0 days (0%) 2011 total: 2 days (<1%) 2010 total: 51 days (14%) 2009 total: 260 days (71%) Updated 06 Jan 2016
Geomagnetic Storms: Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2016 Jan 06 2200 UTC
Wednesday, Jan. 6, 2016
What's up in space
Marianne's Heaven On Earth Aurora Chaser Tours Chasethelighttours.co.uk invites you to join them in their quest to find and photograph the Aurora Borealis. Experience the winter wonderland in the Tromsø Area.
CHANCE OF STORMS: NOAA forecasters estimate a 60% chance of minor G1-class geomagnetic storms today as Earth passes through a stream of high-speed solar wind. Arctic sky watchers should be alert for auroras. Aurora alerts: text or voice
DIAMOND DUST ICE HALOS: As winter deepens in the northern hemisphere, the Arctic atmosphere is filling with crystals of ice. This is producing some beautiful ice halos. They form not only around the sun during the day, but also around headlights at night. Pekka Lähteenmäki photographed samples of both in Jalasjärvi, Finland:
These luminous shapes are caused by light shining through jewel-like crystals called "diamond dust.' Lähteenmäki notes that "You can see individual ice crystals glinting in my photos--especially the night shot."
Atmospheric optics expert Les Cowley has seen halos like these before. He finds the night halos most interesting: "Artificial light halos can have strange forms compared with those made by the sun or moon. The difference is because, unlike sun rays, those from nearby lights are not parallel. The equivalents of sundogs become long streaks. There are even super sundogs. The trumpet-shaped night halo Lähteenmäki photographed was made by hexagonal column crystals floating nearby with their long axes horizontal. It is a cousin of the familiar upper tangent arc--similar, but not the same. Look out at night for a whole new world of halos!"
QUADRANTID METEOR BALLOON: When the annual Quadrantid meteor shower peaked on Jan. 4th, the skies of Spain were cloudy, and rain was falling on astronomers at the Universidad Complutense de Madrid (UCM). Determined to see the shower no matter what, they launched a helium balloon to the stratosphere where the sky was clear. "For the first time ever," reports UCM astronomy postdoc Alejandro Sánchez de Miguel, "we have photographed Quadrantid meteors from the stratosphere--in color and HD." Their video captured as many as half-a-dozen Quadrantids:
The Quadrantids are notoriously difficult to photograph. The meteors are typically faint; moreover, the shower peaks in early January when winter weather often blocks the view of northern skies. The UCM group's successful capture of Quadrantids high above the clouds is a significant accomplishment.
According to Sánchez, there are three good reasons to observe meteor showers using balloons:
"First, the stratosphere is a place where we can avoid bad weather. Lately we have been having terrible weather in Spain!"
"Second, the stratosphere is so transparent. That means we can point our cameras at the horizon and sample a large volume of atmosphere, and capture the maximum number of meteors."
"Third, the stratosphere gives us a new point of view that we can use to calculate meteoroid orbits with higher precision."
Spaceweather.com and Earth to Sky Calculus recently observed the Geminid meteor shower from the stratosphere using a helium balloon of their own: full story. Perhaps a transcontinental collaboration is in the offing. Stay tuned for more pictures from the edge of space.
Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.
On Jan. 6, 2016, the network reported 17 fireballs. (11 sporadics, 5 Quadrantids, 1 December Leonis Minorid)
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]
Near Earth Asteroids
Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.
On January 6, 2016 there were 1649 potentially hazardous asteroids.
These measurements are based on regular space weather balloon flights: learn more.
Approximately once a week, Spaceweather.com and the students of Earth to Sky Calculus fly "space weather balloons" to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing radiation as 2 to 5 dental X-rays. Here is the data from our latest flight, Oct. 22nd:
Radiation levels peak at the entrance to the stratosphere in a broad region called the "Pfotzer Maximum." This peak is named after physicist George Pfotzer who discovered it using balloons and Geiger tubes in the 1930s. Radiation levels there are more than 80x sea level.
Note that the bottom of the Pfotzer Maximim is near 55,000 ft. This means that some high-flying aircraft are not far from the zone of maximum radiation. Indeed, according to the Oct 22th measurements, a plane flying at 45,000 feet is exposed to 2.79 uSv/hr. At that rate, a passenger would absorb about one dental X-ray's worth of radiation in about 5 hours.
The radiation sensors onboard our helium balloons detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV. These energies span the range of medical X-ray machines and airport security scanners.