Space Weather Update: 04/02/2017
By Spaceweather.com, 04/02/2017
THE SUN WAKES UP: Suddenly, solar flare activity is high. With little warning, sunspot AR2644 started exploding yesterday, producing an M4.4-class flare on April 1st followed by an even stronger M5-class flare on April 2nd. Here is the ultraviolet flash from the first explosion, recorded by NASA's Solar Dynamics Observatory.
UV radiation from the April 1st flare caused a brief shortwave radio blackout on the Pacific side of Earth: map. The April 2nd flare caused a similar blackout over the Indian Ocean: map. People who might have noticed these blackouts include ham radio operators and mariners using low-frequency rigs for communication at frequencies below 10 MHz.
The April 1st explosion also hurled a coronal mass ejection (CME) into space: image. The cloud is not heading directly for Earth, but a glancing blow is possible in the days ahead. NOAA analysts are evaluating this possibility now.
NOTE: The source of these flares, AR2644, is not the big sunspot discussed below. While forecasters focused their attention on the big sunspot facing Earth, a lesser sunspot near the sun's western limb exploded instead. Tricky sun.
BIG SUNSPOT FACES EARTH: In a year of few sunspots, AR2645 is remarkable. The young spot has quickly grown from an almost invisible speck into a sprawling behemoth more than 150,000 km wide, with multiple dark cores larger than Earth. And, it is directly facing our planet:
AR2645 has a 'beta-gamma' magnetic field that harbors energy for M-class (moderately strong) solar flares. Any such explosions while the sunspot faces Earth could ionize the top of our planet's atmosphere and alter the normal propagation of radio transmissions around the globe. Shortwave radio blackouts are possible if the sunspot erupts.
Despite its potential, AR2645 has so far been quiet, emitting only a crackling of minor C-flares with minimum effect on Earth. NOAA forecasters estimate a 10% chance of more potent M-flares in the next 24 hours.
FLIGHT OF THE EASTERNAUTS: The cosmic ray monitoring program of Spaceweather.com and Earth to Sky Calculus is not supported by government grants or big corporate sponsors. Instead we rely on you. That is, you and the Easternauts:
On March 2nd, student researchers flew a payload-full of Easter bunnies to the edge of space--and you can have one for $39.95. (Space helmet included!) They make great Easter gifts for young scientists. 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. 2, 2017, the network reported 5 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 2, 2017 there were 1781 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: 02 Apr 17
Sunspot AR2644 has unleashed two significant M-class solar flares in the past 24 hours, and it would seem to pose a threat for more eruptions. Credit: SDO/HMI
Sunspot number: 79
What is the sunspot number?
Updated 02 Apr 2017
Current Stretch: 0 days
2017 total: 27 days (30%)
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 02 Apr 2017
The Radio Sun
10.7 cm flux: 101 sfu
explanation | more data
Updated 02 Apr 2017
Current Auroral Oval:
Coronal Holes: 02 Apr 17
Solar wind flowing from this minor coronal hole should reach Earth on April 2-3, adding its contribution to an already enhanced solar wind environment around Earth. 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 01 2200 UTC
Updated at: 2017 Apr 01 2200 UTC