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Solar wind
speed: 321.2 km/sec
density: 1.9 protons/cm3
explanation | more data
Updated: Today at 2347 UT
X-ray Solar Flares
6-hr max: B6
1809 UT Apr27
24-hr: B7
0038 UT Apr27
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 27 Apr 14
None of these magnetically-simple sunspots poses a threat for strong solar flares. Credit: SDO/HMI
Sunspot number: 46
What is the sunspot number?
Updated 27 Apr 2014

Spotless Days
Current Stretch: 0 days
2014 total: 0 days (0%)
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%)

27 Apr 2014

The Radio Sun
10.7 cm flux: 130 sfu
explanation | more data
Updated 27 Apr 2014

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 1
explanation | more data
Interplanetary Mag. Field
Btotal: 3.2 nT
Bz: 0.7 nT south
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 27 Apr 14
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA. posts daily satellite images of noctilucent clouds (NLCs), which hover over Earth's poles at the edge of space. The data come from NASA's AIM spacecraft. The north polar "daisy" pictured below is a composite of near-realtime images from AIM assembled by researchers at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP).
Noctilucent Clouds
Switch view: Europe, USA, Asia, Polar
Updated at: 02-28-2014 16:55:02
NOAA Forecasts
Updated at: 2014 Apr 27 2200 UTC
0-24 hr
24-48 hr
10 %
10 %
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: 2014 Apr 27 2200 UTC
0-24 hr
24-48 hr
05 %
20 %
01 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
20 %
15 %
30 %
05 %
30 %
Sunday, Apr. 27, 2014
What's up in space

Listen to radar echoes from satellites and meteors, live on listener-supported Space Weather Radio.

Spaceweather Radio is on the air

QUIET SUN: Solar activity is low. Only a few sunspots are facing Earth, and none has the kind of complex magnetic field that harbors energy for strong explosions. NOAA forecasters estimate a waning 10% chance of M-class flares and only a 1% chance of X-flares on April 27th. Solar flare alerts: text, voice

MYSTERIOUS SUN PILLAR ECHOS: Many of us have witnessed sun pillars--columns of light that lance upwards from the horizon just as the sun is rising or setting. They are caused by plate-shaped ice crystals in clouds that bend the rays of the low-hanging sun. While sun pillars are frequently seen, in all seasons and at all latitudes, elusive companions of sun pillars may have been frequently overlooked. They are called sun pillar "echos":

Image credit: Jon Inghram. Larger images: #1, #2

Atmospheric optics expert Les Cowley explains: "13 years ago in Finland, three halo experts saw peculiar 'echoes' straddling an otherwise ordinary sun pillar. They could not be explained and there the matter rested for want of confirmation by another observation. Then, last week, Jon Inghram sent me several sun pillar images. He too had noticed faint 'echoes' on each side of his pillar – the mysterious ice halo was at last confirmed!"

"More details and pictures may be found in an article here. But we still cannot explain them. The Finland observers, Jon and I have each tried simulations using the flattened pyramid crystals invoked to account for elliptical halos. They do not work at all well. We need many more observations! Take plenty of pictures of each pillar. The echoes are easily overlooked or mistaken for cloud patches and have probably been seen many times. Observations under different conditions could help unravel their mystery."

Realtime Space Weather Photo Gallery

RADIO BLACKOUT: An X-class solar flare on April 25th irradiated Earth's upper atmosphere with extreme ultraviolet radiation. Waves of ionization rippled around the dayside of the planet, causing a widespread blackout of shortwave radio transmissions. Radio astronomer Dick Flagg recorded the event at his observatory at the Windward Community College on Oahu:

"This is a dynamic spectrum," explains Flagg. "The vertical axis is frequency (MHz) and the horizontal axis is time (UTC)." All of the horizontal lines corresponding to terrestrial radio stations vanished in the aftermath of the flare.

The active region responsible for the flare rotated off the solar disk yesterday, so even if it flares again, another radio blackout is unlikely this weekend. NOAA forecasters estimate the odds of an X-flare on April 27th to be a scant 1%. Solar flare alerts: text, voice

Realtime Space Weather Photo Gallery

DOOMED MOON OF MARS: Mars has two small moons: Phobos and Deimos. One of them is doomed. Phobos orbits so close to Mars - about 5,800 kilometers above the surface compared to 400,000 kilometers for our own Moon - that gravitational tidal forces are dragging it down. In 100 million years or so Phobos will likely be shattered by tidal shear, the debris forming a decaying ring around Mars.

With the countdown clock clicking, astrophotographer Peter Rosén was determined to photograph the diminutive moon, and on April 24th he succeeded:

"My previous attempt at photographing Phobos and Deimos resulted in Deimos alone, so I tried again last night, slightly changing my setup," says Rosén. "This time I managed to get the even more elusive Phobos at mag. 11.8 , separated only by 11 arcseconds from the blindingly bright Mars at mag. -1.28."

"I inserted the orbital path of both moons to show how much closer Phobos is to the planet compared to Deimos and also that Phobos is on track."

"So why doesn't Deimos show in this 2-frame animation?," he asks. "It was positioned below the planet at a separation of 15 arcseconds at that time and being a full magnitude dimmer (almost 13) it was just invisible."

Realtime Mars Photo Gallery

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 Apr. 25, 2014, the network reported 9 fireballs.
(9 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]

On Apr. 24, 2014, the network reported 19 fireballs.
(15 sporadics, 4 April Lyrids)

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 April 27, 2014 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2014 HP2
Apr 24
3.8 LD
15 m
2014 HU2
Apr 25
3.7 LD
22 m
2014 HM4
Apr 25
1.6 LD
18 m
2014 HW
Apr 27
2.1 LD
10 m
2007 HB15
Apr 28
6.7 LD
12 m
2014 HL2
Apr 28
8.8 LD
26 m
2014 HE5
Apr 29
9.7 LD
36 m
2014 HV2
Apr 29
1.4 LD
30 m
2014 HT46
May 4
7 LD
23 m
2010 JO33
May 17
4 LD
43 m
2005 UK1
May 20
36.7 LD
1.1 km
1997 WS22
May 21
47.1 LD
1.5 km
2002 JC
May 24
48.7 LD
1.4 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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