Space Weather Update: 04/06/2017
By Spaceweather.com, 04/06/2017
SUBSIDING CHANCE OF FLARES: Earlier this week, solar flare activity was high as sunspot AR2644 unleashed a series of M-class explosions. Now, however, the sun is quieting. AR2644 has rotated off the solar disk and no longer poses a threat for Earth-directed flares. Free: Solar Flare Alerts
GIANT 'ELVE' APPEARS OVER EUROPE: On April 2nd, high above a thunderstorm in the Czech republic, an enormous ring of light appeared in the night sky. Using a low-light video camera, amateur astronomer Martin Popek of Nýdek photographed the 300 km-wide donut hovering near the edge of space:
"It appeared for just a split second alongside the constellation Orion" says Popek.
This is an example of an ELVE (Emissions of Light and Very Low Frequency Perturbations due to Electromagnetic Pulse Sources). First seen by cameras on the space shuttle in 1990, ELVEs appear when a pulse of electromagnetic radiation from cloud-to-ground lightning propagates up toward space and hits the base of Earth's ionosphere. A faint ring of deep-red light marks the broad 'spot' where the EMP hits.
"For this to happen, the lightning needs to be very strong--typically 150-350 kilo-Ampères," says Oscar van der Velde, a member of the Lightning Research Group at the Universitat Politècnica de Catalunya. "For comparison, normal cloud-to-ground flashes only reach 10-30 kA."
ELVEs often appear alongside red sprites, which are also sparked by strong lightning. Indeed, Popek's camera caught a cluster of sprites dancing nearby.
ELVEs are elusive--and that's an understatement. Blinking in and out of existence in only 1/1000th of a second, they are completely invisible to the human eye. For comparison, red sprites tend to last for hundredths of a second and regular lightning can scintillate for a second or more. Their brevity explains why ELVEs are a more recent discovery than other lightning-related phenomenon. Learn more about the history and physics of ELVEs here and here.
TIME TO PLANT YOUR SPACE GARDEN: Northern Spring has arrived, and that means it's time to plant your garden. Your SPACE garden, that is. On March 26th, the students of Earth to Sky Calculus flew a payload-full of tomato and sunflower seeds to the edge of space. Carried 115,500 feet high by a giant helium balloon, the packets experienced temperatures as low as -63 C and cosmic ray dose rates 100 times Earth-normal. Here they are at the apex of the flight:
What will these far-out seeds yield? Find out for yourself! For only $39.95 we will send you a packet of space seeds along with control samples that remained on the ground during the flight. Plant them side by side for a backyard science experiment.
Each shipment comes with a card telling the story of the flight and certifying that the seeds have been to the stratosphere and back again. Please specify your seed preference (Beefsteak tomato, cherry tomato, or sunflower) in the comments box at checkout.
More far-out items may be found in the Earth to Sky store. All proceeds support STEM education and our atmospheric cosmic ray monitoring program. .
ACCIDENTAL SATELLITE: 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.
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. 6, 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 April 6, 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: 06 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: 37
What is the sunspot number?
Updated 06 Apr 2017
Current Stretch: 0 days
2017 total: 27 days (28%)
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 06 Apr 2017
The Radio Sun
10.7 cm flux: 85 sfu
explanation | more data
Updated 06 Apr 2017
Current Auroral Oval:
Coronal Holes: 06 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 05 2200 UTC
Updated at: 2017 Apr 05 2200 UTC