Space Weather Update: 12/12/2016
By Spaceweather.com, 12/12/2016
EXITING THE SOLAR WIND STREAM: After four days inside, Earth is exiting a stream of solar wind that has been buffeting our planet’s magnetic field. The glow of Arctic auroras should subside on Dec. 11-12 as the solar wind velocity falls. Browse: aurora sightings.
GEMINID METEORS vs. THE FULL MOON: The Geminid meteor shower peaks this week. Unfortunately, so does the full Moon. Lunar glare will be intense on Dec. 13th and 14th just as the shower climaxes. Bright moonlight will wipe out the normal profusion of faint Geminids, reducing meteor counts more than 5-fold. Now for the good news: Some Geminids are fireballs. Frankie Lucena of Puerto Rio photographed this one on Dec. 11th:
“The only meteors visible last night were the really bright ones,” says Lucena. “The Moon will be getting brighter and brighter the next few nights, which probably means only fireballs will show up in my photos.”
The object floating below the meteor is not a UFO. “It’s a tethered aerostat radarsystem,” explains Lucena. US Customs and Border Protection uses the moored helium balloon for low-level air and ground surveillance.
Geminid meteoroids are gravelly debris from “rock comet” 3200 Phaethon. They hit Earth’s atmosphere traveling ~35 km/s (78,000 mph) and typically disintegrate about 80 km (50 miles) above Earth’s surface. Because of the Geminids’ rocky origin, big meteoroids and bright fireballs are not uncommon. Indeed, NASA’s network of all-sky fireball cameras detected more than half a dozen over the USA on Dec. 11th–numbers that will increase as Earth approaches the heart of the debris stream later this week.
For observers in both hemispheres, the best time to look is during the hours between local midnight and sunrise on Wednesday, Dec. 14th. [sky map]
POLAR STRATOSPHERIC CLOUDS: The stratosphere above the Arctic Circle is getting cold … very cold. That’s the only way to explain these colorful clouds that materialized over Kiruna, Sweden, on Dec. 9th:
“Polar stratospheric clouds are back in the subarctic,” reports photographer Mia Stålnacke. “They were brilliantly beautiful today.”
Icy polar stratospheric clouds (PSCs) form in the lower stratosphere when temperatures drop to around -85ºC. That’s how cold it has to be for ice crystals to form in the very dry stratosphere. High-altitude sunlight shining through tiny ice particles ~10µm across produce the characteristic bright iridescent colors.
“Once seen they are never forgotten,” says atmospheric optics expert Les Cowley. “Polar stratospheric clouds have much more vivid colors than ordinary iridescent clouds, which are very much poor relations and seen frequently all over the world.”
Once thought to be mere curiosities, some PSCs are now known to be associated with the destruction of ozone. Indeed, an ozone hole formed over the UK in Feb. 2016 following an outbreak of ozone-destroying Type 1 PSCs.
“Last winter we had these clouds almost daily for long periods of time,” says Stålnacke. Arctic sky watchers are encouraged to be alert for more in the days ahead. The best time to look is just before sunrise or after sunset.
STUDENT CHRISTMAS SPECIAL: Is there a young scientist in your life? For Christmas, you can give them the gift of exploration. For the holiday season only, we’re reducing the cost of payload space on Earth to Sky Calculus balloons from $500 to only $299.95. Buy an edge of space gift certificate before Dec. 25th and your student can send an experiment, photo, or keepsake item to the stratosphere, completely supported by an Earth to Sky Calculus launch and recovery team.
This is not only a great Christmas gift, but also a good kickstarter for science fair projects. Experiments will be flown and returned along with video footage, GPS tracking, temperature, pressure, altimetry and radiation data.
To take advantage of the discounted rate, payment must be received before Dec. 25th. However, the flight can take place at any time in the next 12 months. A Skype brainstorming session is included with each certificate. Dr. Tony Phillips and other members of the Earth to Sky team will chat with students to help them craft an experiment that will work in the harsh environment of the stratosphere.
More far out Christmas gifts may be found in the Earth to Sky Store. All proceeds support space weather research.
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. 12, 2016, the network reported 29 fireballs.
(17 sporadics, 9 Geminids, 3 sigma Hydrids)
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 12, 2016 there were 1748 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
Readers, thank you for your patience while we continue to develop this new section of Spaceweather.com. We’ve been working to streamline our data reduction, allowing us to post results from balloon flights much more rapidly, and we have developed a new data product, shown here:
This plot displays radiation measurements not only in the stratosphere, but also at aviation altitudes. Dose rates are expessed as multiples of sea level. For instance, we see that boarding a plane that flies at 25,000 feet exposes passengers to dose rates ~10x higher than sea level. At 40,000 feet, the multiplier is closer to 50x. These measurements are made by our usual cosmic ray payload as it passes through aviation altitudes en route to the stratosphere over California.
What is this all about? 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. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Our latest measurements show that cosmic rays are intensifying, with an increase of more than 12% since 2015:
Why are cosmic rays intensifying? The main reason is the sun. Solar storm clouds such as coronal mass ejections (CMEs) sweep aside cosmic rays when they pass by Earth. During Solar Maximum, CMEs are abundant and cosmic rays are held at bay. Now, however, the solar cycle is swinging toward Solar Minimum, allowing cosmic rays to return. Another reason could be the weakening of Earth’s magnetic field, which helps protect us from deep-space radiation.
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.
The data points in the graph above correspond to the peak of the Reneger-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth’s atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.
speed: 513.1 km/sec
density: 5.0 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 1940 UTX-ray Solar Flares
6-hr max: A7 1511 UT Dec12
24-hr: A7 1511 UT Dec12
explanation | more data
Updated: Today at: 1900 UTDaily Sun: 12 Dec 16New sunspot 2617 poses no threat for strong solar flares. Credit: SDO/HMI
Sunspot number: 13
What is the sunspot number?
Updated 12 Dec 2016
Current Stretch: 0 days
2016 total: 26 days (7%)
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 12 Dec 2016
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 3 quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 4.7 nT
Bz: 0.5 nT north
more data: ACE, DSCOVR
Updated: Today at 1939 UTCoronal Holes: 12 Dec 16
There are no large coronal holes on the Earthside of the sun. Credit: NASA/SDO.Noctilucent Clouds The southern season for noctilucent clouds began on Nov. 17th. Come back to this spot every day to see the “daily daisy” from NASA’s AIM spacecraft, which is monitoring the dance of electric-blue around the Antarctic Circle.
Switch view: Ross Ice Shelf, Antarctic Peninsula, East Antarctica, PolarUpdated at: 12-12-2016 16:55:03
Updated at: 2016 Dec 11 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2016 Dec 11 2200 UTCMid-latitudes