You are viewing the page for Sep. 21, 2014
  Select another date:
<<back forward>> -- 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: 437.4 km/sec
density: 1.9 protons/cm3
explanation | more data
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: B8
1752 UT Sep21
24-hr: C5
1155 UT Sep21
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 21 Sept 14
None of these sunspots pose a threat for strong flares. Solar activity remains low. Credit: SDO/HMI
Sunspot number: 75
What is the sunspot number?
Updated 21 Sep 2014

Spotless Days
Current Stretch: 0 days
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%)

Update 21
Sep 2014

The Radio Sun
10.7 cm flux: 119 sfu
explanation | more data
Updated 21 Sep 2014

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Planetary K-index
Now: Kp= 2 quiet
24-hr max: Kp= 3
explanation | more data
Interplanetary Mag. Field
Btotal: 4.7 nT
Bz: -0.0 nT
explanation | more data
Updated: Today at 2347 UT
Coronal Holes: 21 Sep 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: 09-02-2014 12:55:12
NOAA Forecasts
Updated at: 2014 Sep 21 2200 UTC
0-24 hr
24-48 hr
35 %
35 %
10 %
10 %
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 Sep 21 2200 UTC
0-24 hr
24-48 hr
10 %
20 %
01 %
05 %
01 %
01 %
High latitudes
0-24 hr
24-48 hr
15 %
15 %
20 %
25 %
10 %
30 %
Sunday, Sep. 21, 2014
What's up in space

When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.

Northern Lights - a Guide

QUIET WEEKEND: Although the sun is peppered with spots, not one them has the type of complex magnetic field that harbors energy for strong explosions. NOAA forecasters estimate a slight 20% chance of M-class solar flares during what should be a quiet weekend. Solar flare alerts: text, voice

AURORAS LOVE EQUINOXES: On Sept. 23th the sun will cross the celestial equator heading south, marking the end of northern summer. That's good news for high-latitude sky watchers because, for reasons researchers do not fully understand, auroras love equinoxes. At this time of year when the seasons are changing, even gentle gusts of solar wind can spark a nice display of Northern Lights:

Harald Albrigtsen took the picture on Sept. 19th from Kvaløya, Norway. There was no geomagnetic storm predicted that night, and indeed no CME struck our planet. Instead a relatively minor fluctuation in the magnetic orientation of the solar wind sparked the display.

NOAA forecasters estimate a 30% chance of polar geomagnetic storms on Sept 21st, and the probability of Arctic auroras is probably even higher than that. Stay tuned to the realtime photo gallery for sightings. Aurora alerts: text, voice

Realtime Aurora Photo Gallery

FIERY SUNSET: Sky watchers in parts of California are finding that, suddenly, they can view sunspots without a solar telescope. Smoke from the epic King Fire is providing a natural filter. David Wheat photographed the fiery sunset from Tuolumne CA:

"Notice the 3 sunspots on the upper left of the solar disk " points out Wheat.

The fire, which began a week ago in a canyon east of Sacramento, has ballooned in size to 80,000 acres, larger than the city of Portland. Dense smoke has grounded planes and choked the air for hundreds of miles around the blaze--including a Sierra peak where the headquarters of is located. Because the fire is only 10% contained, fiery sunsets will likely continue for days to come.

Warning: Even when the sun is dimmed by smoke and low-hanging clouds, do not look at the sun through magnifying optics. Severe eye damage could result. If you are photographing the sunset, use your camera's digital viewscreen to frame the scene, not the camera's optical viewfinder.

Realtime Aurora Photo Gallery

STUDENTS MEASURE 'FORBUSH DECREASE': On Sept. 12th, a CME hit Earth's magnetic field, igniting the most intense geomagnetic storm of the year. The students of Earth to Sky Calculus quickly launched a helium balloon to the stratosphere to see what effect the storm was having on Earth's upper atmosphere. They expected to measure more radiation than usual. Instead, they measured less. This plot shows a sharp drop in high-energy radiation on Sept. 12th compared to previous flights in May, June, and August:

What caused this counterintuitive drop? Answer: When the CME swept past Earth, it swept aside many of the cosmic rays that normally surround our planet. The effect is called a "Forbush Decrease," named after physicist Scott E. Forbush who first described it in the 20th century.

Wherever CMEs go, cosmic rays are deflected by magnetic fields inside the CME. Forbush decreases have been observed on Earth and in Earth orbit onboard Mir and the ISS. The Pioneer 10 and 11 and Voyager 1 and 2 spacecraft have experienced them, too, beyond the orbit of Neptune. Now high school students have detected a Forbush Decrease in the stratosphere using little more than an insulated lunchbox and a helium balloon.

The balloon's lunchbox-payload is shown here suspended more than 100,000 feet above the Sierras of central California:

Inside the payload, there was an ionizing radiation sensor (energy range: 10.0 KeV to 20.0 MeV), a cryogenic thermometer, multiple GPS altimeters and trackers, and three cameras. During the 2.5 hour flight, the buoy collected more than 50 gigabytes of video and science data ranging in altitude from 8500 ft to 113,700 ft above sea level. The analysis is still underway.

The students wish to thank Caisson Biotech LLC for sponsoring this flight. Note their logo on the upper right corner of the payload!

Readers, if you would like to sponsor an upcoming balloon launch and have your logo flown to the edge of space, please contact Dr. Tony Phillips to make arrangements. The cost of sponsorship is $500. Sponsors receive a complete video of the flight along with advertising exposure on

Realtime Space Weather 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 Sep. 21, 2014, the network reported 19 fireballs.
(19 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 September 21, 2014 there were 1501 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Miss Distance
2009 RR
Sep 16
2 LD
34 m
2006 GQ2
Sep 19
65.9 LD
1.1 km
2014 RW18
Sep 20
6.3 LD
28 m
2014 SG1
Sep 20
0.2 LD
7 m
2009 FG19
Sep 26
34.6 LD
1.1 km
2014 NE52
Sep 30
61.2 LD
1.1 km
2001 EA16
Oct 7
35.5 LD
1.9 km
2011 TB4
Oct 9
5.8 LD
34 m
2010 FV9
Oct 11
8.7 LD
36 m
2003 UC20
Oct 31
52.4 LD
1.0 km
2004 JN13
Nov 18
52.4 LD
4.1 km
1998 SS49
Nov 18
73.9 LD
3.2 km
2005 UH3
Nov 22
44.4 LD
1.3 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...
©2010 All rights reserved. This site is penned daily by Dr. Tony Phillips.
©2013 All rights reserved.