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Solar wind
speed: 650.7 km/sec
density: 0.4 protons/cm3
explanation | more data
Updated: Today at 2348 UT
X-ray Solar Flares
6-hr max: B4
2148 UT Mar21
24-hr: C1
0811 UT Mar21
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 21 Mar 15
Neither of these sunspots poses a threat for strong solar flares. Credit: SDO/HMI

Sunspot number: 27
What is the sunspot number?
Updated 21 Mar 2015

Spotless Days
Current Stretch: 0 days
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 21 Mar 2015

The Radio Sun
10.7 cm flux: 115 sfu
explanation | more data
Updated 21 Mar 2015

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 4
explanation | more data
Interplanetary Mag. Field
Btotal: 10.2 nT
Bz: 8.9 nT north
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 21 Mar 15

There are no large equatorial coronal holes on the Earthside of the sun. Credit: SDO/AIA.
Noctilucent Clouds The southern season for NLCs has come to an end. The last clouds were observed by NASA's AIM spacecraft on Feb. 20, 2015. Now attention shifts to the northern hemisphere, where the first clouds of 2015 should appear in mid-May.
Switch view: Ross Ice Shelf, Antarctic Penninsula, East Antarctica, Polar
Updated at: 02-28-2015 02:55:03
NOAA Forecasts
Updated at: 2015 Mar 21 2200 UTC
0-24 hr
24-48 hr
05 %
05 %
01 %
01 %
Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2015 Mar 21 2200 UTC
0-24 hr
24-48 hr
40 %
40 %
25 %
25 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
10 %
10 %
25 %
25 %
60 %
60 %
Saturday, Mar. 21, 2015
What's up in space

Come to Tromsø and share Marianne's passion for rural photography: invites you to experience "Heaven on Earth" with an aurora, fjord, fishing, whale watching, photography or sightseeing tour.

Chase the Light Tours

WEEKEND GEOMAGNETIC ACTIVITY: Earth's magnetic field above the Arctic Circle is experiencing intermittent geomagnetic storms. These are, essentially, reverberations from the March 17th CME impact amplified to storm-strength by the action of a passing solar wind stream. Polar sky watchers should remain alert for auroras. Aurora alerts: text, voice

SNAPSHOTS FROM THE ECLIPSE: What are the odds? Yesterday, March 20th, just as the Moon was passing in front of the Sun, producing a deep solar eclipse over Europe, the International Space Station flew directly through the eclipse zone. Thierry Legault photographed the split-second transit from Fregenal de la Sierra, Spain:

"I had to drive a lot to find clear skies," says Legault, "but I managed to catch the ISS during the eclipse. The duration of the visible part of the transit was only 0.6s." See the Youtube video!

Meanwhile in the ionosphere.... The eclipse had a dramatic effect on the ionization of Earth's upper atmosphere. Normally, during the day, solar UV radiation breaks apart atoms and molecules, creating a layer of ionized gas hundreds of kilometers above Earth's surface. The Moon, however, blocked those UV rays. Subsequent changes to the ionization structure of atmosphere altered the propagation of radio waves in the eclipse zone. Take a look at these data from Rudolf Slošiar, who operates a VLF (very low frequency) radio monitoring station in Bojnice, Slovakia:

"During the solar eclipse, significant changes in the the D layer of the ionosphere affected the transmission of radio stations I record using my SID monitor, " says Slošiarl. Signals from Iceland were boosted, while radio stations in France and Puerto Rico dropped out.

For more anecdotes from the eclipse, monitor's realtime photo gallery:

Realtime Space Weather Photo Gallery

SPACE YEAST: On March 17th, during the strongest geomagnetic storm of the current solar cycle, and the students of Earth to Sky Calculus launched a Space Weather Buoy to measure the effect of the CME's impact on cosmic rays in the stratosphere. Along with radiation detectors and other sensors, the payload carried some hitchhikers--brewer's and baker's yeast:

During their ascent to the stratosphere, the yeast experienced temperatures as low as -60 C, air pressures only 1% of sea level, and cosmic ray dose rates 40 times Earth-normal.

What can you do with Space Yeast? Bake space bread, brew space beer, or whip up any recipe that calls for yeast. Also, teachers and homeschoolers can conduct some cool classroom experiments.

If you would like a packet of space yeast, you can have one by making a donation of $49.95 to Earth to Sky Calculus. Every flown packet of baker's yeast comes with a control packet that remained behind on Earth during the flight, so you can conduct a properly-controlled scientific experiment. All proceeds support student space weather research. Contact Dr. Tony Phillips to place your order.

AURORAL CHORUS: Earth is a natural radio. Plasma waves coursing through the magnetosphere produce a symphony of "tweeks," "whistlers" and "sferics." Radio receivers operating at very low frequencies (0.1 to 10 kHz) pick up these otherworldy sounds on a daily basis. On March 17th, the symphony reached fever pitch. Radio observer Kevin Palivec reports from Hawley, Texas: "During this week's powerful geomagnetic storm, I picked up a very low frequency (VLF) radio phenomena called 'auroral chorus' for the first time." Click to listen to a sample recording:

"It sounds like birds chirping with the bacon frying in the background," he describes. "I never thought I would detect these signals as far south as Texas. This was one strong magnetic storm."

Readers who wish to monitor Earth's natural radio emisions for themselves can buy a NASA VLF radio receiver kit from the INSPIRE project. It's a fun project for scientists of all ages.

Realtime Aurora Photo Gallery

Realtime Comet Photo Gallery

  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

On Mar. 21, 2015, the network reported 3 fireballs.
(3 sporadics)

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 March 21, 2015 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2015 FK
Mar 19
3.6 LD
37 m
2015 FF
Mar 20
4.2 LD
20 m
2015 EG7
Mar 20
2.7 LD
15 m
2015 FM
Mar 23
6.1 LD
26 m
2015 FW33
Mar 23
9.5 LD
25 m
2015 FC
Mar 26
2.9 LD
20 m
2015 FP
Mar 28
9.6 LD
37 m
2015 FN33
Apr 6
9.8 LD
26 m
2063 Bacchus
Apr 7
76 LD
1.6 km
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.
  Essential web links
NOAA Space Weather Prediction Center
  The official U.S. government space weather bureau
Atmospheric Optics
  The first place to look for information about sundogs, pillars, rainbows and related phenomena.
Solar Dynamics Observatory
  Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever.
  3D views of the sun from NASA's Solar and Terrestrial Relations Observatory
Solar and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
Daily Sunspot Summaries
  from the NOAA Space Environment Center
  the underlying science of space weather
Space Weather Alerts
  more links...
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