You are viewing the page for Apr. 20, 2016
  Select another date:
<<back forward>>
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 358.8 km/sec
density: 5.9 protons/cm3
explanation | more data
Updated: Today at 2349 UT
X-ray Solar Flares
6-hr max: B4
2145 UT Apr20
24-hr: B8
0236 UT Apr20
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 20 Apr 16
Big sunspot AR2529 is about to rotate off the solar disk, leaving the face of the sun mostly blank and quiet. Credit: SDO/HMI

Sunspot number: 28
What is the sunspot number?
Updated 20 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 20 Apr 2016


The Radio Sun
10.7 cm flux: 89 sfu
explanation | more data
Updated 20 Apr 2016

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation
Planetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 2
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 7.7 nT
Bz: 1.4 nT north
explanation | more data
Updated: Today at 2349 UT
Coronal Holes: 20 Apr 16
Solar wind flowing from the indicated coronal hole should reach Earth on April 24-25. 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
SPACE WEATHER
NOAA Forecasts
Updated at: 2016 Apr 20 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
01 %
01 %
CLASS X
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 20 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
05 %
05 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
20 %
20 %
SEVERE
20 %
20 %
 
Wednesday, Apr. 20, 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.

 

LYRID METEOR SHOWER: Earth is approaching a stream of debris from Comet Thatcher, source of the annual Lyrid meteor shower. Normally, sky watchers would see 10 to 20 meteors per hour when the shower peaks on April 21-22. This year, however, visible meteor rates will be sharply reduced by the glare of the full Moon. If you can't see the Lyrids, try listening to them as meteor radar echoes on Space Weather Radio.

SUNSPOT MIRAGE: For many photographers, departing sunspot AR2529 was an irresistible target at sunset. The sunspot's heart-shaped core beamed through the rosy twilight, marking the sun for a unique shot. On April 16th in San Francisco, California, it got a little weird. "Both the sun and the sunspot were stretched and distorted as the sun sank behind the waves of the Pacific Ocean," says Mila Zinkova, who photographed the mirage:


"Notice the vertical stretching of the sunspot," says she. "It was amazing to watch how the appearance of the sun changed as sunset progressed.  Here is the full video."

Atmospheric optics expert Les Cowley explains what happened: "Each sunspot on Mila's picture is a mini mirage. The California Coast is famous for its temperature inversions. Air cooled by the offshore ocean current lies beneath warm air from inland. Sunset sunlight between the layers bends and splits into three mirage images. Two sun slices descend and one upside-down one rises. Nature is not always so simple though. In the case of Mila's sunset, there were multiple small inversion layers. Each inversion layer sliced up the sun like the corrugations of a Chinese lantern. If the air were steady enough we might see that some of the heart shaped sunspots were upside down."

Today, AR2529 has left the disk of the sun.  Good-bye, and thanks for all the photo-ops.

Realtime Space Weather Photo Gallery

A DASH OF GREEN IN ARCTIC TWILIGHT: Around the Arctic Circle, night is vanishing as the summer sun rises over the polar realm. This is creating a short-lived mixture of colors in the sky: aurora green and twilight blue. Aleksander Chernucho sends this picture of the phenomenon from Russia's Kola peninsula:

.

"I think summer vacation is about to begin," says Chernucho, "because these are the last auroras of the 2015-2016 season."

Or, maybe, the second-to-last. An incoming solar wind stream on April 24-25 could add one more dash of green to the twilight before the Arctic sun finally overwhelms the Northern Lights. Monitor the aurora gallery for last-chance sightings.

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 Spaceweather.com.

On Apr. 20, 2016, the network reported 24 fireballs.
(23 sporadics, 1 April Lyrid)

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 20, 2016 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Size
2016 GM2
Apr 16
12.6 LD
41 m
2016 FY12
Apr 17
5.8 LD
24 m
2016 GP221
Apr 18
1.5 LD
29 m
2016 FN13
Apr 19
13.9 LD
13 m
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
23 m
2016 GV221
Apr 21
8.6 LD
42 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
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, 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. 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.
STEREO
  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
Heliophysics
  the underlying science of space weather
IQ Option trading: Find the best binary options brokers and signals from binaryoptionrobotinfo.com
  sponsored link
Kotton Grammer, Search Engine Marketing
  sponsored link
Synergy Spray Foam Insulation of Houston TX
  Protection from the Sun!
  more links...
©2016 Spaceweather.com. All rights reserved. This site is penned daily by Dr. Tony Phillips.
©2013 Spaceweather.com. All rights reserved.