Space Weather Update: 12/31/2015
By Spaceweather.com, 12/31/2015
WEAK IMPACT: As expected, a CME hit Earth’s magnetic field on Dec. 31st (00:30 UT). The impact, however, was weak and did not produce a geomagnetic storm. Auroras are still possible in the hours ahead as Earth moves through the CME’s turbulent wake, but so far this has not been a significant space weather event. Aurora alerts: text or voice
DECAYING SUNSPOT: Big sunspot AR2473, the source of the CME that arrived just hours ago, is breaking apart and losing its potency. Philippe Tosi of Nîmes, France, photographed the sunspot’s decaying core on Dec. 30th:
Tosi inserted a picture of Earth for scale. Even in decay, the sunspot is an awesome thing, with dark condensations and filaments of magnetism that dwarf the largest continents of our planet. Nevertheless, the sunspot’s overall magnetic field has decayed and no longer poses a threat for very strong flares. A stretch of quiet is in the offing. Solar flare alerts: text or voice
POLAR STRATOSPHERIC CLOUDS: Earth’s stratosphere is *not* a cloudy place. On rare occasions, however, during the coldest weeks of northern winter, tiny crystals of ice in the stratosphere gather themselves into swarms called “PSCs”–polar stratospheric clouds. On Dec. 29th, Frank Olsen photographed a rare PSC floating over Sortland, Norway:
“The pastel-colored clouds appeared alongside some faint green auroras,” says Olsen. “I have never seen PSCs and auroras together before.”
Also known as “nacreous” or “mother of pearl” clouds, PSCs form in the lower stratosphere when temperatures drop to around minus 85ºC. That’s how cold it has to be for ice to crystalize in the dry stratosphere.
“I took the picture around 6 p.m., long after sunset,” continues Olsen. “This makes me wonder if the rising moon, just below the horizon, is what illuminated the PSCs.”
High-altitude sunlight–or, in this case, moonlight–shining through tiny ice particles ~10µm across produce the characteristic bright iridescent colors of PSCs. “Polar stratospheric clouds far outshine and have much more vivid colours than ordinary iridescent clouds, which are very much poor relations and seen frequently all over the world,” writes atmospheric optics expert Les Cowley. “Once seen they are never forgotten.”
ARMY OF GREEN MEN — IN SPACE: On Dec. 20th, Spaceweather.com and the students of Earth to Sky Calculus launched their weekly helium balloon to measure cosmic radiation in Earth’s atmosphere. This time, there were 56 hitchikers–a platoon of green army men:
Their mission: to raise awareness of spinal cord injuries. #QuaidsArmy sponsored the flight. On September 20th, 2013, twenty-four year old Quaid Mobus of Warren NJ was in a near fatal ATV accident the night before his sister’s wedding. Quaid was left paralyzed, requiring extensive lifelong medical attention. Since then, the Army of Green Men have been traveling far and wide to support Quaid and others like him. Dec. 20th marked their first trip to the stratosphere. Learn more athttp://www.armyofgreenmen.com/
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. 30, 2015, the network reported 26 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]
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 31, 2015 there were 1647 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: 460.6 km/sec
density: 16.0 protons/cm3
explanation | more data
Updated: Today at 1319 UTX-ray Solar Flares
6-hr max: B7 1152 UT Dec31
24-hr: B7 1152 UT Dec31
explanation | more data
Updated: Today at: 1300 UTDaily Sun: 31 Dec 15Sunspot AR2473 is decaying and no longer has the type of unstable magnetic field that harbors energy for very strong flares. Credit: SDO/HMI
Sunspot number: 34
What is the sunspot number?
Updated 31 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 30 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= 4 unsettled
explanation | more data
Interplanetary Mag. Field
Btotal: 13.3 nT
Bz: 10.3 nT north
explanation | more data
Updated: Today at 1320 UTCoronal Holes: 31 Dec 15
Solar wind flowing from the indicated coronal hole could reach Earth on Jan. 2-3. Credit: SDO/AIA.Noctilucent Clouds The southern season for noctilucent clouds began on Dec. 13, 2015. The coverage of NLCs over Antarctica is rapidly multiplying as 2016 approaches.
Switch view: Ross Ice Shelf, Antarctic Peninsula, East Antarctica, PolarUpdated at: 12-30-2015 15:55:02
Updated at: 2015 Dec 30 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 30 2200 UTCMid-latitudes