Space Weather Update: 01/06/2017
By Spaceweather.com, 01/06/2017
SURROUNDED BY SOLAR WIND: Earth is now fully inside a stream of solar wind flowing from a large hole in the sun’s atmosphere. As a result, NOAA forecasters say there is a 60% chance of polar geomagnetic storms on Jan. 6th. Arctic sky watchers should remain alert for auroras on Friday night. Free: Aurora Alerts
Last night in Scandinavia, solar wind gusts of 700+ km/s sparked bright green Northern Lights. Rayann Elzein sends this picture from Inari, Finland, some 350 km inside the Arctic Circle:
“What a night up here in the Finnish Lapland,” says Elzein. “One glance at the sky was enough to show that we are still inside the solar wind stream. It feels really good to be in the north when such a great show appears.”
SUNSPOTS VANISH, SPACE WEATHER CONTINUES: As 2017 begins, one thing is clear. Sunspots are vanishing. So far, the sunspot number has been zero almost every day: Jan. 1st, 2nd, 4th, 5th, and 6th. A close look at today’s sun reveals no dark cores at all:
The increasingly-blank face of the sun is a herald of Solar Minimum. Sunspot numbers rise and fall with an ~11-year period, slowly oscillating between Solar Max and Solar Min. In 2017, the pendulum is swinging toward minimum.
Contrary to popular belief, space weather does not stop when sunspots vanish. The last few nights are proof: Auroras have been raging around the Arctic Circle. The cause of the display is a solar wind stream flowing from a large hole in the sun’s atmosphere. Such “coronal holes” are common during solar minimum. No sunspots? No problem.
In fact, a lot of interesting things happen during solar minimum. For instance, as sunspots vanish, the extreme ultraviolet output of the sun decreases. This causes the upper atmosphere of Earth to cool and collapse. With less air “up there” to cause orbital decay, space junk accumulates around our planet.
Also during solar minimum, the heliosphere shrinks, bringing interstellar space closer to Earth. Galactic cosmic rays penetrate the inner solar system with relative ease. Indeed, a cosmic ray surge is already underway. Goodbye sunspots, hello deep-space radiation.
See? That blank sun is more interesting than it looks. Stay tuned for updates as the solar cycle changes.
FANTASTIC SUN PILLAR: When the air gets very cold, fantastic things can happen to the setting sun. Peter Rosén of Stockholm, Sweden, witnessed one of them on Jan. 5th. “With freezing temperatures, thermometers reading -10°C, and ice crystals floating in the air, we got a fantastic sun pillar at sunset this afternoon.”
Sun pillars are caused by ice in the air. Plate-shaped crystals ice fluttering down from cirrus clouds catch the rays of the setting sun and spread it into a vertical column.
“Watch a leaf or piece of paper flutter and wobble as it falls,” says atmospheric optics expert Les Cowley. “Ice crystals in the air wobble, too, and this smears the sun’s reflection into a vertical line.”
All around the world, the atmosphere is cold enough 5 to 10 km high to produce these ice crystals. That means sun pillars can be seen anywhere. However, the odds of sighting one improve in cold places like Sweden. Residents of the north should be alert for these beautiful pillars as winter unfolds.
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. 6, 2017, the network reported 6 fireballs.
(5 sporadics, 1 Quadrantid)
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 6, 2017 there were 1757 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: 676.8 km/sec
density: 4.0 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 1845 UTX-ray Solar Flares
6-hr max: A7 1251 UT Jan06
24-hr: A8 0409 UT Jan06
explanation | more data
Updated: Today at: 1800 UTDaily Sun: 06 Jan 17The sun is blank–no sunspots. Credit: SDO/HMI
Sunspot number: 0
What is the sunspot number?
Updated 06 Jan 2017
Current Stretch: 2 days
2017 total: 4 days (67%)
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 06 Jan 2017
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 3 quiet
24-hr max: Kp= 4 unsettled
explanation | more data
Interplanetary Mag. Field
Btotal: 3.6 nT
Bz: -1.0 nT south
more data: ACE, DSCOVR
Updated: Today at 1845 UTCoronal Holes: 06 Jan 17
Solar wind flowing from this major coronal hole should reach Earth on Jan 4th-5th. 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: 01-05-2017 16:55:04
Updated at: 2017 Jan 05 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 05 2200 UTCMid-latitudes