Space Weather Update: 04/05/2017
By Spaceweather.com, 04/05/2017
GOOD-BYE SUNSPOT AR2644: Spitting plasma and crackling with flares, active sunspot AR2644 is disappearing over the sun's western limb. Photographer Philippe Tosi took a parting shot from his observatory in Nîmes, France. "Good-bye sunspot AR2644," he says.
Since April 1st, AR2644 has erupted nearly a dozen times, producing a series of M-class solar flares. Almost every part of Earth experienced a shortwave radio blackout at least once during the fusillade. Earth-effects will subside as the sunspot rotates onto the farside of the sun.
There is still a chance of flares, however. Another large sunspot remains on the solar disk: AR2645. The behemoth active region has an unstable 'beta-gamma-delta' magnetic field that harbors energy for strong explosions. NOAA forecasters estimate a 35% chance of M-class flares and a 15% chance of X-flares on April 5th. Free: Solar Flare Alerts
GEOMAGNETIC STORM: Beating low probabilities of magnetic activity, a minor G1-class geomagnetic storm erupted on April 4th, sparking bright auroras around the Arctic Circle. "I enjoyed the show with my kitty," says Ayumi Bakken, who sends this picture from Fairbanks, Alaska:
ACCIDENTAL SATELLITE SPOTTED: Last Thursday, astronauts spacewalking outside the International Space Station (ISS) had an accident. Just as they were about to install a fabric shield to protect a portion of the station from micrometeoroid impacts ... oops ... the un-tethered shield floated away. On April 3rd, Marco Langbroek of Leiden, the Netherlands, spotted the accidental satellite zipping through the Big Dipper:
"The shield was 1 minute in front of the ISS when I made this image using my Canon EOS 60D digital camera," says Langbroek. "The two bright stars are kappa and iota Uma. "
Weighing about 18 pounds, the 3-inch thick shield measures 5 feet long by 2 feet wide. That's how much of the space station's surface was left exposed to micrometeoroid impacts. No problem. An article in the Washington Post describes how engineers at Mission Control brainstormed a replacement shield using supplies readily available on the ISS.
The stray shield poses no threat to its mother ship. NASA says it is moving away from the ISS and already starting to experience orbital drag. "It will probably re-enter Earth's atmosphere in late summer of 2017," notes Langbroek.
FLIGHT OF THE EASTERNAUTS: Looking for an Easter gift for a young scientist? Submitted for your consideration: The Easternauts. On March 2nd, the students of Earth to Sky Calculus flew a payload-full of Easter bunnies to the edge of space--and you can have one for $39.95. (Space helmet included!)
Carried aloft by a giant helium balloon, these plush bunnies went on a hare-raising journey more than 113,000 feet above Earth's surface. They encountered temperatures as low as -63 C and cosmic ray dose rates more than 100 times Earth normal. Each bunny comes with a greeting card showing the Easternaut in flight and telling the story of its journey to the stratosphere and back again.
More far-out gifts may be found in the Earth to Sky store. All proceeds support STEM education and our atmospheric cosmic ray monitoring program.
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 Apr. 5, 2017, the network reported 10 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 April 5, 2017 there were 1784 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
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.
Daily Sun: 05 Apr 17
Sunspot AR2645 has a 'beta-gamma-delta'-class magnetic field that harbors energy for strong M-class solar flares. Credit: SDO/HMI
Sunspot number: 75
What is the sunspot number?
Updated 05 Apr 2017
Current Stretch: 0 days
2017 total: 27 days (29%)
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 05 Apr 2017
The Radio Sun
10.7 cm flux: 108 sfu
explanation | more data
Updated 05 Apr 2017
Current Auroral Oval:
Coronal Holes: 05 Apr 17
Solar wind flowing from this minor coronal hole could reach Earth onApril 8-9. 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.
Updated at: 02-24-2017 17:55:02
Updated at: 2017 Apr 04 2200 UTC
Updated at: 2017 Apr 04 2200 UTC