Space Weather Update: 01/10/2017
By Spaceweather.com, 01/10/2017
EXITING THE SOLAR WIND STREAM: After almost a week inside, Earth is exiting a stream of solar wind that has sparked bright auroras around the Arctic Circle. Another stream is coming. NOAA forecasters estimate a 40% chance of G1-class geomagnetic storms on Jan. 12th when the solar wind arrives. Free:Aurora Alerts
PILEUS CLOUDS: On Jan. 6th, Peter Lowenstein observed a rainbow-colored saucer over Mutare, Zimbabwe–but it wasn’t a UFO. “This is a classic example of a pileus cloud,” he says.
Pileus clouds form on sunny afternoons when the heat of the summer sun causes cumulus clouds to boil upwards. Roiling toward the sky, cumulus clouds push layers of moist air above them where they cool and condense to form droplet-rich cloud caps or ‘pileus’ (Latin for cap).
Sometimes, as in Mutare on Jan. 6th, pileus clouds form very quickly. In such cases their water droplets tend to be all the same size–the perfect condition for iridescent colors.
Lowenstein took four pictures over a period of just three minutes. “They show the cloudappearing, then changing shape and color,” he says. “One minute later it had disappeared behind the summit of the growing cumulonimbus cloud.”
CORONAL HOLE: A relatively small hole has opened in the sun’s atmosphere. On the sun, “small” means 25 times wider than Earth. NASA’s Solar Dynamics Observatory took this picture of the coronal hole (CH) on Jan. 10th:
Coronal holes are places in the sun’s atmosphere where the magnetic field opens up and allows solar wind to escape. A stream of solar wind flowing from this hole should reach Earth on Jan. 12th. Because the hole is small, the emerging solar wind stream is narrow. Earth will be inside it for only a day or so.
Coincidentally, Earth is expected to cross a fold in the heliospheric current sheet at about the same time. This will boost the chances of a polar geomagnetic storm to 40%, according to NOAA forecasters. Arctic sky watchers should be alert for auroras on Thursday and Friday nights. Free: Aurora Alerts
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 Jan. 10, 2017, the network reported 22 fireballs.
(19 sporadics, 2 Quadrantids, 1 lambda Bootid)
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 January 10, 2017 there were 1759 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
Readers, thank you for your patience while we continue to develop this new section of Spaceweather.com. We’ve been working to streamline our data reduction, allowing us to post results from balloon flights much more rapidly, and 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 over California.
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.
speed: 532.9 km/sec
density: 4.9 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 1801 UTX-ray Solar Flares
6-hr max: B8 1300 UT Jan10
24-hr: B8 1300 UT Jan10
explanation | more data
Updated: Today at: 1800 UTDaily Sun: 10 Jan 17The sun is blank–no sunspots. Credit: SDO/HMI
Sunspot number: 0
What is the sunspot number?
Updated 10 Jan 2017
Current Stretch: 6 days
2017 total: 8 days (89%)
2016 total: 32 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 10 Jan 2017
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: 4.1 nT
Bz: -2.7 nT south
more data: ACE, DSCOVR
Updated: Today at 1759 UTCoronal Holes: 10 Jan 17
Solar wind flowing from this minor coronal hole should reach Earth on or about Jan.12th. Credit: NASA/SDO.Noctilucent Clouds The southern season for noctilucent clouds began on Nov. 17th. Come back to this spot every day to see the “daily daisy” from NASA’s AIM spacecraft, which is monitoring the dance of electric-blue around the Antarctic Circle.
Switch view: Ross Ice Shelf, Antarctic Peninsula, East Antarctica, PolarUpdated at: 01-10-2017 16:55:04
Updated at: 2017 Jan 09 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2017 Jan 09 2200 UTCMid-latitudes