Space Weather Update: 09/21/2016
By Spaceweather.com, 09/21/2016
SHARPENING SPACE WEATHER FORECASTS: It is often said that space weather forecasting is ~50 years behind its terrestrial counterpart. Imagine if the National Hurricane Center predicted that a hurricane would hit tomorrow …somewhere on Earth. Not very specific is it? Yet space weather forecasting is a bit like that. Analysts are often forced to issue global forecasts of geomagnetic activity with little regional detail. This could soon change, however, as a new computer model allows NOAA to pinpoint the effects of geomagnetic storms. Read all about it.
CHINESE SPACE STATION SIGHTED: Last week, on Sept. 15th, China launched a new space station to Earth orbit: Tiangong-2. The 10-meter long spacecraft is only a fraction the size of the ISS, but there is room inside for two tiakonauts (Chinese astronauts) and plenty of science experiments. And in dark skies, it can be seen with the naked eye. On Sept. 20th, Kevin Fetter of Brockville, Ontario, Canada, video-recorded the Tiangong-2 passing by the bright star Zeta Ophiuchi:
“At the time the space station was passing the star, its magnitude was near +5,” estimates Fetter.”It got into the 4th magnitude range just before it disappeared into Earth’s shadow. So it is a naked-eye object, albeit barely.”
Tiangong-2 is the second of three prototype space stations China plans to launch as the country builds toward a Mir-class outpost in the next decade. Tiangong-2’s predecessor, Tiangong-1, is still in orbit and expected to burn up in Earth’s atmosphere sometime in 2017.
Next month, China will launch a crew of two to inhabit the new space station for approximately 30 days. While on board, they will test Tiangong-2’s life support system, and possibly conduct experiments in brain-machine interfacing, atomic clock navigation, and quantum communications.
Ready to see for yourself? Tiangong-2 flyby predictions are available from Heavens Above. “Use the Satellite Database and search for object ‘41765’ labeled ‘OBJECT A,'” advises Fetter. “That’s how to find it.”
SOLAR WIND SPARKS AURORAS: A fast-moving stream of solar wind is buffeting Earth’s magnetic field. In response, auroras are dancing around the Arctic Circle. “The magnetic storm hit us as expected [on Sept.20th]!” reports Rayann Elzein from the UNESCO Ilulissat Icefjord World Heritage site in Greenland. “We had such an amazing show!”
“Imagine the icebergs calving in the background and hearing some whales going about in the sea around the fjord with a huge corona forming above our heads!” describes Elzein. “The bright moon was a superb addition to the magic.”
He also photographed a surprising splash of red among the green. “We could not dream for a better background,” he says.
‘A-BOMB’ SPRITE OVER THE CARIBBEAN: On Sept. 18th, Frankie Lucena of Cabo Rojo, Puerto Rico, photographed an enormous sprite over the Caribbean Sea. For a split-second, the sky was illuminated by a mushroom-shaped flash:
It only looks like a bomb went off. In fact, this is an exotic form of upward-directed lightning. Oscar van der Velde, a member of the Lightning Research Group at the Universitat Politècnica de Catalunya, tells us more about it:
“This type of sprite is often called ‘jellyfish’ or ‘A-bomb,’ and ranks as the largest type of sprite in both horizontal and vertical dimensions,” he says. “It consists of a bright halo approximately 85 km above Earth’s surface surrounding sprite elements with long tendrils reaching down as low as ~30 km above ground level.”
“A-bomb sprites tend to be triggered by a very impulsive positive cloud-to-ground flash,” van der Velde adds.
The curious thing is, Lucena did not observe an instigating lightning bolt. Instead, just before the sprite appeared, he recorded a bright point-like flash of light. “Was it a cosmic ray hitting the camera?” wonders Lucena. Play the entire video to see the flash. Another possibility: The point-like flash could have been a cloud-to-ground strike mostly eclipsed by intervening clouds.
If Lucena did photograph something new triggering a sprite, perhaps it shouldn’t come as a big surprise. The field is relatively new. Although sprites have been seen for at least a century, most scientists did not believe they existed until after 1989 when sprites were photographed by cameras onboard the space shuttle. There is still much to learn.
Cosmic Rays in the Atmosphere
Updated: Sept. 20, 2016 // Next Flight: Sept. 27, 2016
Sept. 20, 2016: Readers, thank you for your patience while we continue to develop this new section of Spaceweather.com. This month we have worked to streamline our data reduction, allowing us to post results from balloon flights much more rapidly. Also, 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.
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 Sep. 21, 2016, the network reported 16 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 September 21, 2016 there were 1730 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: 519.9 km/sec
density: 3.6 protons/cm3
explanation | more data
Updated: Today at 2106 UTX-ray Solar Flares
6-hr max: B4 1501 UT Sep21
24-hr: C1 1151 UT Sep21
explanation | more data
Updated: Today at: 2100 UTDaily Sun: 21 Sep 16None of these small sunspots pose a threat for strong explosions. Solar flare activity remains very low. Credit: SDO/HMI
Sunspot number: 32
What is the sunspot number?
Updated 21 Sep 2016
Current Stretch: 0 days
2016 total: 20 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 Sep 2016
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 4 unsettled
explanation | more data
Interplanetary Mag. Field
Btotal: 4.1 nT
Bz: 0.2 nT north
explanation | more data
Updated: Today at 2105 UTCoronal Holes: 21 Sep 16
Earth is inside a stream of solar wind flowing from the indicated coronal hole. 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 Sep 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 Sep 20 2200 UTCMid-latitudes