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<<back forward>> -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
Solar wind
speed: 489.4 km/sec
density: 4.7 protons/cm3
explanation | more data
Updated: Today at 2349 UT
X-ray Solar Flares
6-hr max: B1
2121 UT Apr23
24-hr: B1
1311 UT Apr23
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 23 Apr 16
Sunspot AR2533 has a stable magnetic field that poses no threat for strong solar flares. Credit: SDO/HMI

Sunspot number: 22
What is the sunspot number?
Updated 23 Apr 2016

Spotless Days
Current Stretch: 0 days
2016 total: 0 days (0%)
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 23 Apr 2016

The Radio Sun
10.7 cm flux: 77 sfu
explanation | more data
Updated 23 Apr 2016

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation
Planetary K-index
Now: Kp= 3 quiet
24-hr max: Kp= 3
explanation | more data
Interplanetary Mag. Field
Btotal: 9.8 nT
Bz: 6.5 nT north
explanation | more data
Updated: Today at 2349 UT
Coronal Holes: 23 Apr 16
Solar wind flowing from the indicated coronal hole should reach Earth on April 23-24. Credit: SDO/AIA.
Noctilucent Clouds The southern season for noctilucent clouds began on Dec. 13, 2015. It is expected to end in late February or March 2016.
Switch view: Ross Ice Shelf, Antarctic Peninsula, East Antarctica, Polar
Updated at: 02-12-2016 16:55:02
NOAA Forecasts
Updated at: 2016 Apr 23 2200 UTC
0-24 hr
24-48 hr
01 %
01 %
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: 2016 Apr 23 2200 UTC
0-24 hr
24-48 hr
25 %
20 %
05 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
30 %
25 %
30 %
25 %
Saturday, Apr. 23, 2016
What's up in space

Looking for a unique Mother's Day gift? How about Space Roses? Proceeds from the sale of these far-out blooms support student space weather research.


GEOMAGNETIC STORM IN PROGRESS: The solar wind is having an effect on Earth, after all. A mild G1-class geomagnetic storm is in progress on April 23rd as Earth moves through a stream of solar wind flowing from a coronal hole on the sun. High-latitude sky watchers should be alert for auroras. Aurora alerts: text or voice

THE MICRO-MOON: We've all heard of supermoons--full Moons that are extra big and bright because they occur close to Earth. This week's full moon was the opposite--a micro-moon. April's full Moon was as much as 14% smaller than other full Moons of 2016. Marek Nikodem photographed the shrunken orb over a cement factory in Piechcin, Poland:

"Hot smoke rising over the factory distorted the shape of the lunar disk and made it seem that the Moon was being drawn into the smokestack," says Nikodem. Not even a micromoon, however, is small enough to fit inside a chimney. Photos taken moments later reveal the disk floating free.

Full Moons vary in size because of the oval shape of the Moon's orbit. The Moon follows an elliptical path around Earth with one side ("perigee") about 50,000 km closer than the other ("apogee"). Full Moons that occur on the apogee side of the Moon's orbit seem a bit smaller and dimmer than usual. That's what happened on April 22nd. The Moon became full at 05:24 UT only 13 hours after apogee--a coincience that reduced the size of the lunar orb.

The supermoon will return on Nov. 14 when the Moon becomes full at perigee. Stay tuned for that.

Realtime Space Weather Photo Gallery

SPACE WEATHER PROBE TAKES SELFIE: Last December, Joyce and Tad Lhamon of Seattle, Washington, bought their 12-year-old grandson Barrett a far-out Christmas gift--that is, a trip to the edge of space. In exchange for this gift certificate, Barrett could fly any experiment he wanted to the stratosphere onboard an Earth to Sky Calculus helium balloon. He thought about it for months and, after discarding many ideas, Barrett decided to fly a convex mirror. The payload's cameras could look into the mirror and take a new kind of "space selfie." Would it work? On April 17th, we flew Barrett's experiment, and the results were better than anyone dreamed:


" and the students of Earth to Sky Calculus have flown more than 150 missions to the edge of space monitoring cosmic rays and stress-testing microbes. We've never seen our payload quite like this before.

A particularly interesting sequence of images shows the balloon exploding above the payload 117,100 feet above Earth. The following video frames are separated by only 1/30th of a second: #1, #2, #3, #4. Note how the payload remains motionless during the explosion. It takes more than a second for the shock wave from the explosion to propagate down the long cord connecting the payload to the balloon.

Congratulations, Barrett, on a very successful experiment!

Realtime Space Weather 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. 23, 2016, the network reported 26 fireballs.
(18 sporadics, 8 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 23, 2016 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2016 GB222
Apr 21
4.4 LD
20 m
2016 GC1
Apr 21
8.8 LD
20 m
2016 GZ220
Apr 21
10.1 LD
25 m
2016 GV221
Apr 21
8.6 LD
43 m
2016 HA
Apr 22
6.5 LD
26 m
2016 GD207
Apr 22
4.4 LD
29 m
2016 FH12
Apr 23
7.9 LD
21 m
2016 GC222
Apr 24
14 LD
31 m
2016 FY3
Apr 25
6.4 LD
310 m
2001 VG5
Apr 28
52.4 LD
1.8 km
2016 HK
May 1
4.6 LD
52 m
2014 US115
May 1
9.4 LD
52 m
2008 TZ3
May 5
13.1 LD
355 m
2014 JG55
May 8
7.6 LD
7 m
2016 GS2
May 18
3.4 LD
109 m
2009 DL46
May 24
6.2 LD
215 m
1997 XF11
Jun 10
70 LD
1.8 km
2015 XZ378
Jun 13
9.7 LD
16 m
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
Situation Report -- Oct. 30, 2015 Stratospheric Radiation (+37o N)
Cosmic ray levels are elevated (+6.1% above the Space Age median). The trend is flat. Cosmic ray levels have increased +0% in the past month.
Sept. 06: 4.14 uSv/hr (414 uRad/hr)
Sept. 12: 4.09 uSv/hr (409 uRad/hr)
Sept. 23: 4.12 uSv/hr (412 uRad/hr)
Sept. 25: 4.16 uSv/hr (416 uRad/hr)
Sept. 27: 4.13 uSv/hr (413 uRad/hr)
Oct. 11: 4.02 uSv/hr (402 uRad/hr)
Oct. 22: 4.11 uSv/hr (411 uRad/hr)
These measurements are based on regular space weather balloon flights: learn more.

Approximately once a week, 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. Our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing radiation as 2 to 5 dental X-rays. For example, here is the data from a flight on Oct. 22, 2015:

Radiation levels peak at the entrance to the stratosphere in a broad region called the "Pfotzer Maximum." This peak is named after physicist George Pfotzer who discovered it using balloons and Geiger tubes in the 1930s. Radiation levels there are more than 80x sea level.

Note that the bottom of the Pfotzer Maximim is near 55,000 ft. This means that some high-flying aircraft are not far from the zone of maximum radiation. Indeed, according to the Oct 22th measurements, a plane flying at 45,000 feet is exposed to 2.79 uSv/hr. At that rate, a passenger would absorb about one dental X-ray's worth of radiation in about 5 hours.

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.

  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
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