Space Weather Update: 03/08/2016
By Spaceweather.com, 03/08/2016
THE SOLAR ECLIPSE IS ABOUT TO BEGIN: Later today, there’s going to be a total eclipse of the sun. It begins at sunrise on March 9th over the islands of Indonesia. That’s the afternoon of March 8th in the United States. Sky watchers inside the narrow path of totality, which cuts across the Pacific Ocean from Sumatra to the waters north of Hawaii, can feel the touch of the Moon’s cool shadow and behold the sun’s corona. Stay tuned to the realtime photo gallery for the first sightings.
DON’T FORGET THE PARTIAL ECLIPSE: Mainstream media attention is focused on today’s total eclipse of the sun. Fair enough. Totality is a mesmerizing experience that turns ordinary people into lifelong eclipse chasers. But don’t forget about the partial eclipse. As this animated map created by graphic artist Larry Koehn shows, the sun will be partially covered over almost half of the planet:
Unlike the path of totality, which is very narrow, the partial eclipse zone is huge. It touches places as far apart as Alaska (20% coverage), Hawaii (65%), Australia (0% to 60%), China (0% to 40%), Japan (20%), and Papua New Guinea (70%). This is good, because a partial eclipse is total fun.
The first thing to remember about a partial eclipse is don’t stare at it. Even the tiniest sliver of sun left uncovered by the Moon can hurt your eyes. Instead, look at the ground. Beneath a leafy tree, you might be surprised to find hundreds of crescent-shaped sunbeams dappling the grass. Overlapping leaves create a natural array of pinhole cameras, each one casting an image of the crescent-sun onto the ground beneath the canopy.
No trees? Try this trick: Criss-cross your fingers waffle-style and let the sun shine through the matrix of holes. You can cast crescent suns on sidewalks, driveways, friends, cats and dogs—you name it. Hand shadows are fun, too, like the crescent-eyed turkey shown above.
Because the partial eclipse lasts for more than an hour, there is plenty of time for shadow play and photography using safely-filtered telescopes and cameras. The view from Hawaii and Alaska, where the eclipse occurs near sunset, should be especially beautiful.
ATMOSPHERIC RADIATION EXPERIMENT IN PROGRESS: The students ofEarth to Sky Calculus are flying from Los Angeles to Indonesia to observe the March 9th solar eclipse. Among other things, they are carrying a cosmic ray balloon payload with GPS tracking and 4 radiation sensors. This allows them to measure radiation inside the airplane. Scroll past their flight path to learn more about the experiment:
During the trip, the students will be crossing both the Arctic Circle and the equator in the same 24 hour period, allowing them to gather radiation data rapidly over a wide range of latitude. This will build upon their ongoing study of aviation radiation which, before now, has been limited to latitudes in the continental USA.
Radiation inside airplanes comes from deep space. Galactic cosmic rays are accelerated toward our planet by supernova explosions and other violent events in the cosmos. They penetrate the walls of aircraft with ease and have prompted the International Commission on Radiological Protection (ICRP) to classify pilots as occupational radiation workers. Today’s experiment will probe how Earth’s magnetic field at different latitudes protects pilots and passengers from aviation radiation. Stay tuned for results!
ANTI-CREPUSCULAR RAYS: The sun was setting yesterday in the Sierra Nevada mountains of central California when a fan of shadowy rays sprang up from the horizon. They looked like ordinary sunset rays except for one thing–“the sun was on the opposite side of the sky,” says Katharine Allen, who witnessed the display and photographed it while she was walking her dogs:
“What was it?” she asks. The answer: Anti-crepuscular rays.
Behind Allen’s back, the setting sun dipped behind some ragged clouds. The edges of those clouds cast shadows–immense tubes of darkness–that arced all the way across the sky to converge on the opposite horizon. Such shadows are called “anti-crepuscular rays.”
Anti-crepuscular rays are not rare, but they are delicate and often go unnoticed. The next time you see shadows emerging from the sunset, turn around. There may be something beautiful waiting right behind your back.
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 Mar. 7, 2016, the network reported 13 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 March 8, 2016 there were 1683 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.
Cosmic Rays in the Atmosphere
Situation Report — Oct. 30, 2015Stratospheric Radiation (+37o N)
Cosmic ray levels are elevated(+6.1% above the Space Age median). The trend is flat. Cosmic ray levels have increased +0% in the past month.
Sept. 06: 4.14 uSv/hr (414 uRad/hr)
Sept. 12: 4.09 uSv/hr (409 uRad/hr)
Sept. 23: 4.12 uSv/hr (412 uRad/hr)
Sept. 25: 4.16 uSv/hr (416 uRad/hr)
Sept. 27: 4.13 uSv/hr (413 uRad/hr)
Oct. 11: 4.02 uSv/hr (402 uRad/hr)
Oct. 22: 4.11 uSv/hr (411 uRad/hr)
These measurements are based on regular space weather balloon flights: learn more.
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. Our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing radiation as 2 to 5 dental X-rays. For example, here is the data from a flight on Oct. 22, 2015:
Radiation levels peak at the entrance to the stratosphere in a broad region called the “Pfotzer Maximum.” This peak is named after physicist George Pfotzer who discovered it using balloons and Geiger tubes in the 1930s. Radiation levels there are more than 80x sea level.
Note that the bottom of the Pfotzer Maximim is near 55,000 ft. This means that some high-flying aircraft are not far from the zone of maximum radiation. Indeed, according to the Oct 22th measurements, a plane flying at 45,000 feet is exposed to 2.79 uSv/hr. At that rate, a passenger would absorb about one dental X-ray’s worth of radiation in about 5 hours.
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.
speed: 454.2 km/sec
density: 4.6 protons/cm3
explanation | more data
Updated: Today at 1427 UTX-ray Solar Flares
6-hr max: C1 1306 UT Mar08
24-hr: C1 1306 UT Mar08
explanation | more data
Updated: Today at: 1400 UTDaily Sun: 08 Mar 16Not one of these relatively small sunspots poses a threat for strong flares. Solar activity remains very low. Credit: SDO/HMI
Sunspot number: 61
What is the sunspot number?
Updated 08 Mar 2016
Current Stretch: 0 days
2016 total: 0 days (0%)
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 08 Mar 2016
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 4 unsettled
explanation | more data
Interplanetary Mag. Field
Btotal: 3.0 nT
Bz: 0.1 nT south
explanation | more data
Updated: Today at 1409 UTCoronal Holes: 08 Mar 16
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA.Noctilucent Clouds The southern season for noctilucent clouds began on Dec. 13, 2015. It is expected to end in late February 2016.
Switch view: Ross Ice Shelf, Antarctic Peninsula, East Antarctica, PolarUpdated at: 02-12-2016 16:55:02
Updated at: 2016 Mar 07 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2016 Mar 07 2200 UTCMid-latitudes