Space Weather Update: 12/21/2015
By Spaceweather.com, 12/21/20115
GEOMAGNETIC STORM: A G1-class geomagnetic storm is in progress on Dec. 21st as Earth moves through the wake of a CME that struck our planet’s magnetic field Saturday. Ayumi Y. Bakken photographed the display from Fairbanks, Alaska:
“What a wonderful night!” says Bakken. “The aurora was dancing all night starting around 7pm. Even my car reflected the green light.”
NOAA forecasters estimate a 40% chance of continued storming tonight, waning to 20% on Dec. 22nd as CME effects subside. High-latitude sky watchers should be alert for auroras. Aurora alerts: text or voice
UNIQUE CHRISTMAS GIFT: Is there a young scientist in your life? For Christmas, you can give them the gift of exploration–specifically, a trip to the edge of space:
To raise funds for its student research program, Earth to Sky Calculus is selling a limited number of Holiday Season balloon flights carrying … whatever you desire. Small experiments. Holiday or anniversary photos. Business advertisements. The sky is the limit. Young people receiving this gift can design their own experiment and attend the launch via Skype. The gift includes a brainstorming session via Skype with Dr. Tony Phillips and the students of Earth to Sky. Cost: $500. Buy now and receive the certificate in time for Christmas. Contact Dr. Tony Phillips to book your flight.
COLORFUL LIGHTS OVER CHILE: Geomagnetic storms are brewing, but not every colorful light in the night sky is an aurora. For instance, Yuri Beletsky sends this picture taken Dec. 17th from the Atacama desert in Chile:
“These are not auroras. We just witnessed an amazing display of airglow,” says Beletsky. “It was so intense that you could not see many stars close to the horizon – the sky was literally shining.”
Airglow is aurora-like phenomenon in the upper atmosphere caused by a variety ofchemical reactions. It begins during the day when solar ultraviolet radiation ionizes atoms and molecules. At night, those same atoms and molecules glow as they re-capture lost electrons. The green in Beletsky’s photo comes from oxygen atoms in a layer 90-100 km high; the red is probably associated with OH ions at an altitude of about 85 km. The wavy structure of the glow is due to high-altitude gravity waves, which alter the temperature and density structure of the upper atmosphere.
“Airglow is much less intense than aurora,” continues Beletsky. “The display I saw looked, to the naked eye, like a series of black-and-white waving bands. The full color of the display was easily captured, however, by my digital camera.”
All Sky Fireball Network
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 Dec. 20, 2015, the network reported 27 fireballs.
(17 sporadics, 9 December Leonis Minorids, 1 Geminid)
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 December 21, 2015 there were 1646 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:Asteroid
Notes: LD means “Lunar Distance.” 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.
Cosmic Rays in the Atmosphere
Situation Report — Oct. 30, 2015Stratospheric Radiation (+37o N)
Cosmic ray levels are elevated(+6.1% above the Space Age median). The trend is flat. Cosmic ray levels have increased +0% in the past month.
Sept. 06: 4.14 uSv/hr (414 uRad/hr)
Sept. 12: 4.09 uSv/hr (409 uRad/hr)
Sept. 23: 4.12 uSv/hr (412 uRad/hr)
Sept. 25: 4.16 uSv/hr (416 uRad/hr)
Sept. 27: 4.13 uSv/hr (413 uRad/hr)
Oct. 11: 4.02 uSv/hr (402 uRad/hr)
Oct. 22: 4.11 uSv/hr (411 uRad/hr)
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.
speed: 372.9 km/sec
density: 2.9 protons/cm3
explanation | more data
Updated: Today at 1300 UTX-ray Solar Flares
6-hr max: M1 1019 UT Dec21
24-hr: M2 0103 UT Dec21
explanation | more data
Updated: Today at: 1300 UTDaily Sun: 21 Dec 15Big sunspot AR2470 poses a slight threat for M-class solar flares. Credit: SDO/HMI
Sunspot number: 33
What is the sunspot number?
Updated 21 Dec 2015
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 20 Dec 2015
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 4 unsettled
24-hr max: Kp= 6 storm
explanation | more data
Interplanetary Mag. Field
Btotal: 15.0 nT
Bz: 0.4 nT south
explanation | more data
Updated: Today at 1259 UTCoronal Holes: 20 Dec 15
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA.Noctilucent Clouds The southern season for noctilucent clouds is about to begin. Monitor the daily daisies, below, from NASA’s AIM spacecraft for the first wisps of electric blue above Antarctica.
Switch view: Ross Ice Shelf, Antarctic Peninsula, East Antarctica, PolarUpdated at: 12-20-2015 16:55:02
Updated at: 2015 Dec 20 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2015 Dec 20 2200 UTCMid-latitudes