Space Weather Update: 10/21/2016
By Spaceweather.com, 10/21/2016
THE SUN IS FLAT-LINING: With no sunspots actively flaring, the sun’s X-ray output is flat-lining. Solar activity is very low and is likely to remain so throughout the weekend. NOAA forecasters say there is no more than a 1% chance of strong flares in the next three days. Free: Space Weather Alerts.
A HOLE IN THE SUN’S ATMOSPHERE: A large coronal hole is rotating into view over the sun’s eastern limb, and it is spewing a complicated stream of solar wind into space. This image from NASA’s Solar Dynamics Observatory shows the outlines of the structure on Oct. 21st:
Coronal holes are places in the sun’s atmosphere where the magnetic field opens up and allows solar wind to escape. Big holes like this one typically appear once or twice a month.
An emerging stream of solar wind will sweep past Earth about five days from now, possibly sparking polar geomagnetic storms and auroras when it arrives. Forecasts will improve in the days ahead as the yawning structure turns more directly toward our planet. We will be able to look down down into it and get a better idea of its dimensions and magnetic topology. Stay tuned for updates as the solar wind approaches.
METEORS FROM HALLEY’S COMET: Earth has entered a stream of debris from Halley’s comet, source of the annual Orionid meteor shower. Forecasters expect the shower to peak during the night of Oct. 20-21 with rates of 10 to 20 meteors per hour. The best time to look is during the hours before local sunrise on Oct. 21st when Orion is high in the sky. [sky map]
Unfortunately, as the sky map above shows, the bright gibbous Moon will be high in the sky, too. Only the brightest Orionids will be visible through the glare.
Now for the good news: This meteor shower produces a fair number of fireballs–that is, meteors brighter than the planet Venus, easily seen in bright moonlight. Just last night, NASA’s network of all-sky meteor cameras recorded 11 Orionid fireballs over the USA. Amateur astronomer Thomas Ashcraft caught this beauty streaking over his observatory in rural New Mexico:
“As you can see in the video, brilliant occasional Orionid fireballs are still quite visible even in bright moonlight,” says Ashcraft.
Readers, when you play the video, don’t forget to turn up the volume. You can hear the signals of distant radio transmitters reflecting from the ionized trail of the fireball. “The full radio reflection lasted nearly two minutes,” he says.
Got clouds? Listen to the shower live on Space Weather Radio.
CHINA’S NEW SPACE STATION IS NOW OCCUPIED: On Oct 18th, Chinese astronauts onboard the Shenzhou 11 spacecraft docked with China’s new space station, the Tiangong 2. Moments before the link-up, cameras on the Shenzhou 11 photographed the station’s docking port as the two craft flew in tandem 250 miles above Earth:
This means there are now two occupied space stations orbiting Earth. The other one, of course, is the International Space Station (ISS). Compared to the ISS, the Tiangong 2 is small. Indeed, it nearly doubled in size when the Shenzhou 11 joined it. Linked together, the merged spacecraft will orbit Earth for the next month providing a home in space about the size of a double decker bus.
If all goes as planned, astronauts Jing Haipeng and Chen Dong will more than double the record for the longest-duration Chinese crewed mission, extending the mark from 15 days to 33 days. They will spend their time conducting science experiments and rehearsing procedures for future missions: Within a few years, China plans to start launching modules for a much larger Mir-class space station slated for completion in the 2020s.
Cosmic Rays in the Atmosphere
Updated: Sept. 29 2016 // Next Flight: Oct. 1, 2016
Sept. 20, 2016: 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.
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 Oct. 21, 2016, the network reported 42 fireballs.
(25 sporadics, 17 Orionids)
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 October 21, 2016 there were 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.
speed: 376.8 km/sec
density: 8.8 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 1952 UTX-ray Solar Flares
6-hr max: B1 1642 UT Oct21
24-hr: B1 1642 UT Oct21
explanation | more data
Updated: Today at: 1900 UTDaily Sun: 21 Oct 16Sunspot AR2602 is quiet and stable. Solar flare activity remains very low. Credit: SDO/HMI
Sunspot number: 16
What is the sunspot number?
Updated 21 Oct 2016
Current Stretch: 0 days
2016 total: 21 days (8%)
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 21 Oct 2016
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 1 quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 3.6 nT
Bz: 2.6 nT north
more data: ACE, DSCOVR
Updated: Today at 1951 UTCoronal Holes: 21 Oct 16
A large coronal hole is emerging over the sun’s eastern limb. Credit: NASA/SDO.Noctilucent Clouds NASA’s AIM spacecraft has suffered an anomaly, and a software patch is required to fix it. As a result, current noctilucent cloud images will not return until late September 2016.
Switch view: Europe, USA, Asia, PolarUpdated at: 08-06-2016 16:55:02
Updated at: 2016 Oct 20 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2016 Oct 20 2200 UTCMid-latitudes