Spotless Days Current Stretch: 0 days
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 01 Dec 2015
Geomagnetic Storms: Probabilities for significant
disturbances in Earth's magnetic field are given for three activity levels: active, minor
Updated at: 2015 Nov 30 2200 UTC
Tuesday, Dec. 1, 2015
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.
INTERPLANETARY SPACECRAFT TO BUZZ EARTH ON DEC. 3RD: Japan's Hayabasa 2 spacecraft, on a six year mission to catch and sample an asteroid, will fly past Earth on Dec. 3rd. Earth's gravity will slingshot the spacecraft toward its target, 162173 Ryugu, which Hayabasa 2 is expected to reach in July 2018. This animation from JAXA (the Japanese space agency) previews the flyby:
Many readers have never heard of Hayabasa 2. It is an amazing mission. After the spacecraft reaches Ryugu in 2018, it will orbit the asteroid for a year and a half. During that time, Hayabasa 2 will deploy four landers and drop a copper impactor to blow a hole in the asteroid's side. Hayabasa 2 itself will touch down on the asteroid, briefly, at least once to collect samples excavated by the impactor. In Dec. 2019, the spacecraft will leave the asteroid and use its ion engines to return to Earth, carrying precious samples of Ryugu. Ambitious? Yes. But if Hayabasa 2 completes even a fraction if its mission, it will be a success.
The spacecraft is small (mass: 590 kg, dimensions: 2 x 1.6 x 1.25 meters), so when it flies by Earth it will not be very bright. A telescope will be required to see it.
Veteran satellite observer Rick Baldridge notes that "for the US west coast, the spacecraft gets barely 7 degrees above the western horizon at closest approach. Observers in Alaska, Hawaii and Japan are favored. Ephemerides for specific locations may be obtained on the JPL HORIZONS website." Additional charts, a ground track map, and data are available in Japanese at this URL.
OFFICE LIGHTS: Imagine walking into your place of work, flipping on the light switch, and the room is flooded with green. Welcome to the world of nature photographer Oliver Wright, who has pitched his tent in Sweden's Abisko National Park for the winter. "This is my office for the next 4 months," he explains:
"Great aurora in Abisko last night," says Wright. "It was a really big display with green lights moving quite quickly and some red fringing at times."
The display was caused by a solar wind stream, which hit Earth's magnetic field on Nov. 30th. For several hours, a G1-class geomagnetic storm lit up the Arctic Circle from Scandinavia to Alaska. "I am looking forward to more big displays in the months ahead," he says.
How about tonight? NOAA forecasters estimate a 40% chance of polar geomagnetic storms on Dec. 1st as Earth slowly exits the solar wind stream. Aurora alerts: text or voice
(UPDATED) TWO CMEs, BOTH MISS EARTH: A pair of CMEs--one bright and one faint--billowed away from the sun on Nov. 29th. According to NOAA storm tracks, neither will hit Earth. Click to view a movie from the Solar and Heliospheric Observatory:
The bright CME (pictured above) will miss Earth; it came from an explosion on the far side of the sun and is not heading in our direction. The faint one, which appears later in the movie, was launched by a minor eruption in the magnetic canopy of sunspot AR2459. Although the sunspot was facing Earth, the CME sailed wide of our planet. Solar flare alerts: text or voice
Every night, a network
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 Nov. 29, 2015, the network reported 7 fireballs.
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]
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.
December 1, 2015 there were 1638
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.