Space Weather Update: 01/30/2017
By Spaceweather.com, 01/30/2017
HUGE HOLE IN THE SUN’S ATMOSPHERE: A huge hole has opened in the sun’s atmosphere, and it is spewing a stream of solar wind directly toward Earth. NASA’s Solar Dynamics Observatory photographed the structure, which stretches more than halfway across the face of the sun:
This is a “coronal hole” (CH)–a region where the sun’s magnetic field opens up and allows solar wind to escape. NASA’s STEREO spacecraft recently sampled the stream flowing from this hole and the velocity was unusually high: 750 km/s. Such a fast-moving stream will almost surely spark Arctic auroras when it arrives on Feb. 1st.
The action could begin even before the stream arrives. NOAA forecasters say there is a 65% chance of geomagnetic storms on Jan. 31st when Earth crosses through a fold in the heliospheric current sheet–a vast undulating system of electrical currents in space shaped like the skirt of a ballerina. Earth dips in and out of it all the time. These crossings are called “solar sector boundary crossings,” and they can trigger their own form of geomagnetic activity. Free: Aurora alerts.
DID THIS RAINBOW JUST BREAK THE LAWS OF PHYSICS? When the temperature dips below freezing, rainbows vanish, right? Rainbows require liquid raindrops, and frozen water doesn’t do the trick. Yesterday in Alaska, however, a rainbow appeared that seemed to defy the simple laws of physics. John Dean photographed the pale arc over Nome:
“It was not raining,” says Dean. “The temperature was 25 F and a light snow storm had just passed through about an hour before. This is a first for me, and it has me perplexed.”
Atmospheric optics expert Les Cowley explains what happened: “This is definitely a rainbow made by water drops, even though it was so cold. Ice spheres, hail or snowflakes cannot make them because a rainbow needs almost perfectly spherical, smooth and transparent water drops. This bow is broad, telling us that the water drops were small. They were also probably quite high up, and might even have been supercooled below the normal freezing point of water.”
Supercooled raindrops can form when droplets of water fall through layers of subfreezing air. Droplets containing specks of dust or even microbes readily freeze as ice crystals form around the impurities. But when rain droplets are especially pure, they can remain in a liquid state even when the temperature drops below freezing.
Hence — the “supercooled rainbow.” High latitude sky watchers should be alert for these rare rainbows as strange Arctic weather grips the North in winter 2017.
FAR-OUT VALENTINE’S GIFT: Nothing says “I love you” like a bear from space. To raise money for their cosmic ray research program, the students of Earth to Sky Calculus have flown a payload-full of Valentine’s bears to the edge of space. This was a special flight, timed to photograph the bears at sunset in the stratosphere, wrapped in the romantic light of the fading sun 98,000 feet above Earth’s surface:
You can have one for $49.95. Each bear comes with a Valentine’s card showing the bears in flight and telling the story of their trip to the stratosphere.
More far-out Valentine’s gifts may be found in the Earth to Sky store. All proceeds support cosmic ray balloon flights and STEM education.
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 Jan. 30, 2017, the network reported 17 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 January 30, 2017 there were 1767 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: 517.4 km/sec
density: 7.4 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 1557 UTX-ray Solar Flares
6-hr max: A9 1426 UT Jan30
24-hr: A9 0008 UT Jan30
explanation | more data
Updated: Today at: 1500 UTDaily Sun: 30 Jan 17Neither of these sunspots poses a threat for strong solar flares. Credit: SDO/HMI
Sunspot number: 24
What is the sunspot number?
Updated 30 Jan 2017
Current Stretch: 0 days
2017 total: 10 days (34%)
2016 total: 32 days (9%)
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 Jan 2017
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 2 quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 8.1 nT
Bz: 0.2 nT south
more data: ACE, DSCOVR
Updated: Today at 1555 UTCoronal Holes: 30 Jan 17
Solar wind flowing from this large coronal hole could reach Earth as early as Jan. 31st, although Feb. 1st is more likely. Credit: NASA/SDO.Noctilucent Clouds The southern season for noctilucent clouds began on Nov. 17, 2016. 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: 01-30-2017 03:55:03
Updated at: 2017 Jan 29 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2017 Jan 29 2200 UTCMid-latitudes