Space Weather Update: 09/07/2016
By Spaceweather.com, 09/07/2016
ASTEROID FLYBY: Today, Sept. 7th, a truck-sized asteroid is flying past Earth only 21,000 miles above our planet’s surface. At closest approach, 2016 RB1 will actually skim the orbital-zone of geosynchronous satellites. The odds of an impact with any spacecraft are, however, negligibly low. Gianluca Masi photographed the 12-meter-wide space rock from Ceccano, Italy, just hours ago: image.
WHY ARE JUPITER’S AURORAS SO RED? Many readers have asked why Jupiter’s auroras, described in a news item below, are so impressively red. In fact, they are infra-red. Juno science team member Alberto Adriani explains:
“The colors of auroras are determined by the gas that is present in the atmosphere. On Earth the gas generating the beautiful red or green auroras is oxygen. On Jupiter, the atmospheric gas is hydrogen. Two distinct auroras coexist over the poles of Jupiter: Ultraviolet auroras created by hydrogen in its molecular form (H2) and infrared auroras created by the hydrogen ion H3+.”
AURORAS ON JUPITER: On Aug. 27th, for the first time ever, NASA’s Juno spacecraft swooped over Jupiter’s south pole. The flyby revealed an astonishing vortex of infra-red light:
“While we knew that the flyby of Jupiter’s south pole might reveal the planet’s southern aurora, we were still amazed to see it for the first time,” says Alberto Adriani from the Istituto di Astrofisica e Planetologia Spaziali in Rome. Adriani is a co-investigator on the Jovian Infrared Auroral Mapper (JIRAM), the instrument that took the picture.
Another instrument on Juno named “Waves” detected low-frequency (<100 kHz) radio signals coming from Jupiter’s aurora-zone. To make these signals audible, mission scientists at the University of Iowa shifted the signals into the frequency range of human hearing. The audio begins about 30 seconds into this movie:
If the auroras of Jupiter sound mysterious–that’s because they are.
Unlike Earth, which lights up in response to solar activity, Jupiter makes its own auroras. The power source is the giant planet’s own rotation. Although Jupiter is ten times wider than Earth, it manages to spin around 2.5 times as fast as our little planet. As any freshman engineering student knows, if you spin a magnet you’ve got an electric generator. And Jupiter is a very big magnet. Induced electric fields accelerate particles toward Jupiter’s poles where the aurora action takes place. Remarkably, many of the particles that rain down on Jupiter’s poles appear to be ejecta from volcanoes on Io. How this complicated system actually works is a puzzle.
DIAMOND DUST ICE HALOS IN ANTARCTICA: In the icy lands around the south pole, ordinary things take on an exotic quality. Count sundogs among them. B. Sudarsan Patro photographed these from the Bharati Indian Base Station in the Larsemann Hills of Antarctica on Sept. 5th:
Sundogs–that is, rainbow colored splashes of light on either side of the sun–are seen around the world on a daily basis. They are caused by ice crystals in high cirrus clouds.
Ice crystals in the air around Antarctica, however, are special. They are “diamond dust.” These tiny, jewel-like crystals of ice form on cold days in the air near ground level. When they catch the rays of the low-hanging sun, the results can be spectacular, with sundogs that glitter intensely as the dust drifts by. A close up of Patro’s sundogs shows this effect in action:
Each speck and circle of light in this image is sunlight glistening through an individual crystal of diamond dust.
“Sept. 5th marked the Ganesh Chatrurthi, the Hindu festival in honor of the elephant-headed god, Ganesha,” says Patro. “We went outside to celebrate and saw this diamond dust halo in the sky. It was wonderful.”
For more wonderful shots from around the world, browse the realtime photo gallery:
Cosmic Rays in the Atmosphere
Updated: Sept.3, 2016 // Next Flight: Sept. 10, 2016
Sept. 3, 2016: On Sept. 2nd, Spaceweather.com and the students of Earth to Sky Calculus conducted a successful transcontinental launch of two space weather balloons–one from New Hampshire and another from California. The New Hampshire balloon recorded the highest levels of atmospheric radiation since our monitoring program began two years ago. Students are reducing the data now, and we will report the results in the coming week.
While you wait, here is a shot of the Atlantic coast of Maine taken during the Sept. 2nd balloon flight from an altitude of 118,000 feet:
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 almost 13% 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.
THIS RESEARCH IS CROWD-FUNDED: The cosmic ray research presented on Spaceweather.com is done by students, driven by curiosity, and funded entirely by readers. Our latest flight over California on Aug. 21st was sponsored by World Tech Toys of Valencia CA. In exchange for their generous donation of $750, we flew a toy Striker Drone to the edge of space:
HD video and poster-quality images of the drone in space are now being used by World Tech Toys for marketing and outreach–an out-of-this-world bargain.
Our next flights on Sept. 2nd and Sept. 10th need sponsors. Would you like to assist? Contact Dr. Tony Phillips to make arrangements.
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. 7, 2016, the network reported 41 fireballs.
(38 sporadics, 1 September epsilon Perseid, 1 alpha Aurigid, 1 Northern iota Aquariid)
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 7, 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: 498.2 km/sec
density: 2.4 protons/cm3
explanation | more data
Updated: Today at 2121 UTX-ray Solar Flares
6-hr max: B1 1742 UT Sep07
24-hr: B6 1040 UT Sep07
explanation | more data
Updated: Today at: 2100 UTDaily Sun: 07 Sep 16Sunspot AR2585 is large but quiet. Solar activity remains low. Credit: SDO/HMI
Sunspot number: 32
What is the sunspot number?
Updated 07 Sep 2016
Current Stretch: 0 days
2016 total: 20 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 07 Sep 2016
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 3 quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 4.7 nT
Bz: 0.4 nT north
explanation | more data
Updated: Today at 2125 UTCoronal Holes: 07 Sep 16
Earth is exiting a broad 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 06 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 06 2200 UTCMid-latitudes