Space Weather Update: 05/29/2016
By Spaceweather.com, 05/29/2016
CHANCE OF STORMS ON MEMORIAL DAY: NOAA forecasters estimate a 55% chance of G1-class geomagnetic storms on May 30th when Earth enters a high-speed stream solar wind flowing from this coronal hole:
Coronal holes are places in the sun’s atmosphere where the magnetic field opens up and allows solar wind to escape. When solar wind leaves the sun, it carries some of the sun’s magnetic field with it to Earth. This is key: Magnetic fields in the emerging stream have a negative polarity (“negative Bz“). Such fields can pry open a crack in Earth’s magnetosphere, allowing solar wind to pour in and fuel geomagnetic storms. High-latitude sky watchers should therefore be alert for auroras on May 30th, especially in the southern hemisphere where darkening autumn skies favor visibility of faint lights. Aurora alerts: text, voice.
NOCTILUCENT CLOUD SEASON BEGINS: It’s official. The 2016 season for noctilucent clouds is underway. NASA’s AIM spacecraft spotted them on May 24th, and now observers on the ground are seeing them, too. Andy Stables sends this picture from Milovaig on the Isle of Skye, Scotland:
“The wispy electric-blue clouds appeared near midnight on May 27th,” says Staples.
NLCs are Earth’s highest clouds. Seeded by meteoroids, they float at the edge of space more than 80 km above the planet’s surface. The clouds are very cold and filled with tiny ice crystals. When sunbeams hit those crystals, they glow electric-blue.
Noctilucent clouds first appeared in the 19th century after the eruption of super-volcano Krakatoa. At the time, people thought the clouds were caused by the eruption, but long after Krakatoa’s ash settled, the clouds remained. In those days, NLCs were a polar phenomenon confined mainly to the Arctic. In recent years they have intensified and spread with sightings as far south as Utah and Colorado. Some researchers believe the intensification is a sign of climate change.
Early-season NLCs are always found at high-latitudes–e.g., Canada, the British isles, Siberia and Scandinavia. To people in those areas, we offer the followingobserving tips: Look west 30 to 60 minutes after sunset when the sun has dipped 6o to 16o below the horizon. If you see luminous blue-white tendrils spreading across the sky, you may have spotted a noctilucent cloud.
SPACE BEARS MAKE GOOD GRADUATION GIFTS: Around the USA, high school seniors are preparing to receive their diplomas. Nothing says “you’re on your way up!” better than a graduation gift from the Edge of Space. On May 25th, the students of Earth to Sky Calculus flew a family of “graduation grizzlies” 27 km (90,000 feet) above Earth’s surface:
Outfitted with space helmets and a diploma, the intrepid Ursidae survived cosmic rays, ultra-low temperatures, and the near-vacuum of the stratosphere. For $49.95 you can have one of these bears along with a unique Graduation card showing the bears floating at the top of Earth’s atmosphere. Buy one now.
Sales of the bears support student space weather research. In fact, the bears pictured above were hitchhiking on a payload equipped with radiation sensors. We send the sensors to the stratosphere every week to monitor increasing levels of cosmic rays. Visit the Earth to Sky store to support this crowd-funded research.
SPRITES (AND SOMETHING MORE) OVER OKLAHOMA: On May 23rd, an enormous swarm of sprites flickered and danced across the top of a thunderstorm in Oklahoma. Almost 400 miles away in New Mexico, amateur astronomer Thomas Ashcraft trained his cameras on the display. He captured the sprites–and something more:
“Note the dendritic upward spray in the midst of the sprite cluster,” points out Ashcraft. “That is a possible ‘pop-through gigantic jet’–a rare event.”
Ashcraft has posted a video of the event with VLF-ELF radio emissions he recorded as a soundtrack. Turn up the volume: “The deep bass sound of the lightning stroke sounds like a distant shotgun blast in the night,” he says.
What is a pop-through gigantic jet? Lightning scientist Oscar van der Velde of the Technical University of Catalonia explains: “A cluster of sprites can actually warp Earth’s ionosphere, bringing it down from its usual altitude of 90 km to only 40 km.” This sets the stage for the jet.
“The sprite cluster triggers an upward-directed discharge which in the past received fancy names as ‘troll’ or ‘palm tree’,” says van der Velde. “A satellite-based study by Taiwanese researchers in 2012 found them similar to gigantic jets–large isolated discharges reaching from the thundercloud toward the ionosphere. In case of a ‘pop-through gigantic jet,’ the lowering of the ionosphere is not uniform and the jet may then reach higher than the bottom tendrils of the sprite.”
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. Now “sprite chasers” routinely photograph sprites–and more!–from their own homes. “They are easily detected by certain cameras,” says van der Velde, “and if a storm is in the mood, you may record one every few minutes.” Give it a try!
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 May. 29, 2016, the network reported 8 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 May 29, 2016 there were 1703 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: 484.0 km/sec
density: 2.1 protons/cm3
explanation | more data
Updated: Today at 2007 UTX-ray Solar Flares
6-hr max: B1 1450 UT May29
24-hr: B7 0656 UT May29
explanation | more data
Updated: Today at: 2000 UTDaily Sun: 29 May 16New sunspot AR2549 has a simple magnetic field that poses no threat for strong flares. Solar activity remain slow. Credit: SDO/HMI
Sunspot number: 31
What is the sunspot number?
Updated 29 May 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 29 May 2016
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 3 quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 7.3 nT
Bz: 2.6 nT south
explanation | more data
Updated: Today at 2010 UTCoronal Holes: 29 May 16Solar wind flowing from the indicated coronal hole could reach Earth on May 30. Credit: SDO/AIA.Noctilucent Clouds Images from NASA’s AIM spacecraft are once again appearing on Spaceweather.com. Check back daily for space-based sightings of noctilucent clouds.
Switch view: Europe, USA, Asia, PolarUpdated at: 05-28-2016 19:55:02
Updated at: 2016 May 28 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2016 May 28 2200 UTCMid-latitudes