Space Weather Update: 07/31/2016
By Spaceweather.com, 07/31/2016
COSMIC RAYS AND HEART DISEASE: A new study just published in the journal Scientific Reports concludes that Apollo astronauts who traveled to the Moon were 4 to 5 times more likely to die of cardiovascular disease than astronauts who never went beyond low Earth orbit. The culprit: cosmic rays. According to the authors “[space radiation] induces a sustained vascular endothelial cell dysfunction. Such impairment is known to lead to occlusive artery disease, and may be an important risk factor for cardiovascular disease among astronauts exposed to deep space radiation.” Something to think about if you’re planning a trip to Mars….
INCOMING SOLAR STORM: During the late hours of July 28th, a filament of magnetism erupted on the sun, slingshotting a cloud of plasma (CME) into space. Scroll past the movie of the CME to learn when it will hit Earth:
NOAA analysts have computer-modeled the trajectory of this CME, and they say it is likely to strike Earth’s magnetic field late on August 1st. This is not a major storm cloud, but it is not alone. A solar wind stream is following closely behind it. The double blow could strongly disturb Earth’s polar magnetic field. NOAA forecasters say there is a 70% chance of G1 or G2-class geomagnetic storms on Aug. 2nd. Aurora alerts: text or voice
A MYSTERIOUS FORM OF AURORA: Humans have been watching the aurora borealis for thousands of years, with scientific studies of the phenomenon underway for centuries. Despite all that watching and studying, however, there are still some auroral forms that remain a mystery–namely, the “proton arc.” This one appeared over the Grande Cache area of Alberta, Canada, on July 29th:
“As I was driving to the Kakwa river, I saw a purple ‘proton arc’ crossing the sky from east to west, pulsing and dancing with the Northern lights,” says photographer Catalin Tapardel. “Quite a show….”
Aurora photographers see these structures from time to time–tight ribbons of light, sometimes red, sometimes green, writhing across the night sky. They are commonly called “proton arcs.”
Yet aurora scientists say they probably have nothing to do with protons.
“My opinion, and I believe the consensus of most aurora scientists, is that these arcs are not proton related, ” says Jason Ahrns, a researcher at the University of Alaska Fairbanks, “but I don’t know what does cause them.”
“Ordinary auroras we see from the ground and space are caused by electrons precipitating down into the atmosphere,” says Dennis Gallagher of the NASA Marshall Space Flight Center. “Protons can cause auroras, too, but they are different. For one thing, proton auroras are brightest in the UV part of the spectrum, invisible to the human eye.”
There is some visible light from proton auroras, but the structures they make are not tight and filamentary, but rather broad and diffuse–“in part because thegyroradius of protons is large,” says Ahrns. In other words, massive protons circle around magnetic fields in broad lazy arcs unlike lightweight electrons, which can tightly circle magnetic fields to form narrow structures.
Ahrns photographed an authentic proton aurora in February 2014: photo. “It appearance matched the description of proton arcs in the scientific literature – ‘a dim and diffuse glow’ with ‘very little structure in the observed brightness’ with a total brightness of only a few kiloRayleighs, which is just on the verge of visual threshold (Lummerzheim 2001).”
So what are the “proton arcs” often photographed by amateur aurora chasers? “I don’t know,” says Ahrns, “but it is something many of us would like to get to the bottom of!” For more examples of this mystery in the sky, browse theProton Arc Photo Gallery.
WHERE NO DUCK HAS GONE BEFORE: Yes, that really is a Vulcan rubber duck! The students of Earth to Sky Calculus flew the pointy-eared water bird to the stratosphere on July 19, 2016, as part of their ongoing program to monitor cosmic rays in the stratosphere. Here he is at the apex of the flight, 109,580 ft:
“Mr Squawk” hitchhiked on a helium balloon payload that carried an array of X-ray/gamma-ray sensors. By launching these sensors 3 or 4 times a month, the students have shown that cosmic rays are intensifying–a trend that affects mountain climbers, air travelers, high-altitude drones and astronauts on the International Space Station.
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 Jul. 31, 2016, the network reported 66 fireballs.
(56 sporadics, 5 Perseids, 3 alpha Capricornids, 2 Southern delta Aquariids)
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 August 1, 2016 there were 1714 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: 359.9 km/sec
density: 4.5 protons/cm3
explanation | more data
Updated: Today at 2249 UTX-ray Solar Flares
6-hr max: B2 2141 UT Jul31
24-hr: B2 2141 UT Jul31
explanation | more data
Updated: Today at: 2359 UTDaily Sun: 31 Jul 16Sunspot AR2570 is small and quiet. Solar activity remains low. Credit: SDO/HMI
Sunspot number: 13
What is the sunspot number?
Updated 31 Jul 2016
Current Stretch: 0 days
2016 total: 18 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 31 Jul 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: 3.3 nT
Bz: 2.8 nT north
explanation | more data
Updated: Today at 2250 UTCoronal Holes: 31 Jul 16
Solar wind flowing from the indicated coronal hole should reach Earth on ~Aug. 3rd. 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: 07-29-2016 16:04:17
Updated at: 2016 Jul 31 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2016 Jul 31 2200 UTCMid-latitudes