You are viewing the page for May. 21, 2015
  Select another date:
<<back forward>>
You entered an invalid date. This is yesterday's edition.
SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids Internet Shopping Sites high quality binoculars excellent weather stations all-metal reflector telescopes rotatable microscopes
 
Solar wind
speed: 387.9 km/sec
density: 1.7 protons/cm3
explanation | more data
Updated: Today at 2348 UT
X-ray Solar Flares
6-hr max: B4
1704 UT May21
24-hr: C1
0706 UT May21
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 21 May 15
Not one of these sunspots poses a threat for strong flares. Solar activity is low. Credit: SDO/HMI

Sunspot number: 61
What is the sunspot number?
Updated 21 May 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 May 2015


The Radio Sun
10.7 cm flux: 106 sfu
explanation | more data
Updated 21 May 2015

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 1
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 5.1 nT
Bz: 0.8 nT north
explanation | more data
Updated: Today at 2349 UT
Coronal Holes: 21 May 15

There are no large coronal holes on the Earthside of the Sun. Credit: SDO/AIA.
Noctilucent Clouds The northern season for NLCs is about to begin. Readers should monitor the "daily daisies" below for first sightings from NASA's AIM spacecraft.
Switch view: Europe, USA, Asia, Polar
Updated at: 05-20-2015 17:55:02
SPACE WEATHER
NOAA Forecasts
Updated at: 2015 May 21 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: 2015 May 21 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
10 %
MINOR
01 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
20 %
20 %
MINOR
20 %
20 %
SEVERE
10 %
10 %
 
Thursday, May. 21, 2015
What's up in space
 

Learn to photograph Northern Lights like a pro. Sign up for Peter Rosen's Aurora Photo Courses in Abisko National Park.

 
Lapland tours

QUIET SUN: With no sunspots actively flaring, solar activity is low. According to NOAA, the odds of a significant solar flare (M- or X-class) today are no more than 1%. Solar flare alerts: text, voice

SATURN'S RINGS TO SURGE IN BRIGHTNESS: This Friday night, May 22nd, Saturn will be "at opposition"--that is, opposite the sun in the skies of Earth. The ringed planet rises in the east at sunset and soars through the southern sky at midnight, a golden "star" in the constellation Scorpius. [sky map]

Whenever Saturn is at opposition, its rings surge in brightness. Why? Scroll down for the explanation. On the way, check out these photos taken by amateur astronomer Anthony Wesley on May 19th:

"This is an animation of two Saturn images about 10 minutes apart," says Wesley, who used a 16-inch telescope in Australia. It shows gaps in Saturn's rings, clouds in the planet's atmosphere, and a famous hex-shaped storm around Saturn's north pole.

Getting such Hubblesque results from a backyard telescope requires a combination of good seeing and long years of experience. Wesley is one of the world's top amateur astrophotographers and he routinely produces images like this. Observers with less experience can take good photos, too, especially in the nights ahead as Saturn's rings brighten.

The brightening of Saturn's rings is called the "opposition effect." Saturn's rings are made of frozen chunks ranging in size from dust to houses. Sunlight directly backscattered from those ice particles causes the ring system to shine even more than usual for a few days around opposition. The exact mechanism involves shadow-hiding and possibly coherent backscattering.

If you have a telescope, take a look! Or sign up for a live view of Saturn from Slooh--no telescope required.

Realtime Space Weather Photo Gallery

SPRITE SEASON BEGINS: High above Earth in the realm of meteors and noctilucent clouds, a strange and beautiful form of lightning dances at the edge of space. Researchers call the bolts "sprites"; they are red, fleeting, and tend to come in bunches. Note to sky watchers: Sprite season is underway. Martin Popek photographed these specimens over Nydek, Czech republic, on May 13th:

One night later, May 14th, near Santa Fe, New Mexico, "I captured my first sprites of the season," reports photographer Jan Curtis. "The thunderstorm that produced them was about 200 miles to my south-southwest."

Because sprites are associated with thunderstorms, they tend to occur in late spring and summer. Thunderstorm season is sprite season.

"Sprites are a true space weather phenomenon," explains lightning scientist Oscar van der Velde of the Technical University of Catalonia, Spain. "They develop in mid-air around 80 km altitude, growing in both directions, first down, then up. This happens when a fierce lightning bolt draws lots of charge from a cloud near Earth's surface. Electric fields [shoot] to the top of Earth's atmosphere--and the result is a sprite. The entire process takes about 20 milliseconds."

Although sprites have been seen for at least a century, most scientists did not believe they existed until after 1989 when sprites were photographed by cameras onboard the space shuttle. Now "sprite chasers" routinely photograph sprites from their own homes. "I used up a Watec 910HX security camera with UFOCapture software to catch my sprites," says Popek. Give it a try!

diagram: How to Look for Sprites (used with permission of sky-fire.tv)

Realtime Sprite 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 Spaceweather.com.

On May. 19, 2015, the network reported 13 fireballs.
(13 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 May 21, 2015 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Size
2015 KG
May 18
14.3 LD
18 m
2015 JF
May 18
9 LD
24 m
2015 HT9
May 25
12.1 LD
28 m
2015 KH
May 29
14.3 LD
53 m
2005 XL80
Jun 4
38.1 LD
1.0 km
2012 XB112
Jun 11
10.1 LD
2 m
2005 VN5
Jul 7
12.6 LD
18 m
2015 HM10
Jul 7
1.1 LD
73 m
1994 AW1
Jul 15
25.3 LD
1.4 km
2011 UW158
Jul 19
6.4 LD
565 m
2013 BQ18
Jul 20
7.9 LD
38 m
1999 JD6
Jul 25
18.8 LD
1.6 km
2005 NZ6
Aug 6
76.5 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.
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
Space Weather Alerts
   
  more links...
©2015 Spaceweather.com. All rights reserved. This site is penned daily by Dr. Tony Phillips.
©2013 Spaceweather.com. All rights reserved.