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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 341.9 km/sec
density: 2.6 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 2345 UT
X-ray Solar Flares
6-hr max: A6
2021 UT Sep21
24-hr: A6
2021 UT Sep21
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 21 Sep 19
The sun is blank--no sunspots. Credit: SDO/HMI

Sunspot number: 0
What is the sunspot number?
Updated 21 Sep 2019

Spotless Days
Current Stretch: 18 days
2019 total: 187 days (71%)
2018 total: 221 days (61%)
2017 total: 104 days (28%)
2016 total: 32 days (9%)
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%)
2008 total: 268 days (73%)
2007 total: 152 days (42%)
2006 total: 70 days (19%)

Updated 21 Sep 2019


Thermosphere Climate Index
today: 4.18
x1010 W Cold
Max: 49.4
x1010 W Hot (10/1957)
Min: 2.05
x1010 W Cold (02/2009)
explanation | more data: gfx, txt
Updated 21 Sep 2019

The Radio Sun
10.7 cm flux: 67 sfu
explanation | more data
Updated 21 Sep 2019

Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation
Planetary K-index
Now: Kp= 1 quiet
24-hr max: Kp= 3
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 4.0 nT
Bz: -1.4 nT south
more data: ACE, DSCOVR
Updated: Today at 2345 UT
Coronal Holes: 21 Sep 19


Solar wind flowing from this coronal hole could hit Earth's magnetic field on Sept. 23-24.
Credit: SDO/AIA

Noctilucent Clouds The northern season for noctilucent clouds has ended. NASA's AIM spacecraft is no longer detecting electric-blue clouds around the Arctic Circle.
Switch view: Europe, USA, Asia, Polar
Updated at: 09-03-2019 13:55:02 UT
SPACE WEATHER
NOAA Forecasts
Updated at: 2019 Sep 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: 2019 Sep 21 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
05 %
25 %
MINOR
01 %
05 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
15 %
30 %
SEVERE
10 %
30 %
 
Saturday, Sep. 21, 2019
What's up in space
       
 

Solar minimum is here - but even now strangely beautiful auroras are dancing around the poles. Deep inside the Arctic Circle, the expert guides of Aurora Holidays in Utsjoki, Finland, can help you chase them. Book now!

 

THE SOLAR WIND IS COMING: A hole in the sun's atmosphere is facing Earth and spewing a stream of solar wind in our direction. Estimated time of arrival: Sept. 23rd. Arriving on the first day of northern autumn, the gaseous material could spark a nice display of equinox auroras around the Arctic Circle. Aurora alerts: SMS Text.

EQUINOX AURORAS: Auroras love equinoxes. At this time of year even a gentle gust of solar wind can spark bright auroras around the Arctic Circle. Petra Schneider sends this example of the phenomenon from Hamarøy, Norway:

No geomagnetic storm was in progress on Sept. 21st when Schneider took the picture. Instead, a minor solar wind stream was brushing against Earth's magnetic field--barely elevating the background density and speed of gaseous material flowing around our planet.

What happened? It's called the "Russell-McPherron effect."  During weeks around equinoxes, cracks open in Earth's magnetic field, allowing solar wind to enter and ignite Arctic auroras. This effect will continue in the nights ahead as the autumnal equinox approaches and the solar wind continues to blow. Happy Equinox!

Realtime Aurora Photo Gallery
Free:
Spaceweather.com Newsletter
  

SPACE STATION FLIES THROUGH A RAIKOKE SUNSET: On June 22nd, astronauts on board the International Space Station photographed a volcanic eruption so large, it could be seen from Earth orbit. The Raikoke volcano in the Kirul Islands sent a plume of gas all the way up into the stratosphere. Three months later, a photographer from a small village in Iran saw the ISS fly through a purple "Raikoke sunset."

"At the end of the day on Sept. 19th, I was waiting for the space station to appear when the sky turned purple," says Ali Norouzi Varankeshi of Baraghan, Iran. "It was a volcanic sunset, and the ISS flew right through it. I photographed the flyby from a hillside overlooking the city lights of nearby Karaj."

Months after the astronauts first noticed Raikoke, its emissions are still lingering in the upper atmosphere. Fine volcanic aerosols in the stratosphere scatter blue light which, when mixed with ordinary sunset red, produces a purple hue. Last month, the Ulawun volcano in New Guinea also sent sulfurous gases into the stratosphere, enhancing the effect.

People around the world are seeing these purple sunsets--not every night, because the volcanic gas is patchy, but often. The purple color is usually preceded by a yellow arch hugging the horizon. As the sun sets, violet beams emerge from the yellow, overlapping to fill the western sky with a soft purple glow.

Realtime Volcanic Sunset Photo Gallery
Free: Spaceweather.com Newsletter

THE SPACE PEARL: It's the first pearl in the stratosphere. On Aug. 19, 2019, the students of Earth to Sky Calculus launched a cosmic ray balloon to the edge of space, 104,002 ft high. This sterling silver pearl necklace went along for the ride:

You can have it for $169.95. The students are selling these pearls to support their cosmic ray ballooning program. Each cultured "space pearl" comes with greeting card showing the necklace in flight and telling the story of its journey to the edge of space and back again. These make great birthday and Christmas gifts.

Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education


Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter

  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 Sep. 21, 2019, the network reported 22 fireballs.
(20 sporadics, 2 southern Taurids)

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, 2019 there were 2018 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Velocity (km/s)
Diameter (m)
2019 JF1
2019-Sep-16
11.2 LD
4.3
62
2019 SD
2019-Sep-16
5.8 LD
10.2
29
2018 FU1
2019-Sep-16
18.4 LD
4.7
16
2019 SJ
2019-Sep-16
0.6 LD
8.7
11
2019 RC
2019-Sep-16
17.4 LD
15.1
157
2019 SN
2019-Sep-17
19.2 LD
7.4
30
2019 SC
2019-Sep-19
1.4 LD
13.5
13
2019 RP2
2019-Sep-20
8.5 LD
1.6
6
2019 ST
2019-Sep-20
5.5 LD
12.9
46
2017 SL16
2019-Sep-21
7.9 LD
6.5
25
2017 SM21
2019-Sep-21
11.5 LD
9.6
20
2019 SD1
2019-Sep-21
0.7 LD
24.1
7
2019 RE2
2019-Sep-21
19.7 LD
8.7
43
2019 RB3
2019-Sep-21
19 LD
11.8
50
2019 SX
2019-Sep-21
1.1 LD
14.4
4
2019 QZ1
2019-Sep-22
12.5 LD
8.2
77
2019 SG1
2019-Sep-22
2.2 LD
17.4
10
523934
2019-Sep-24
10.9 LD
22.3
257
2019 QY3
2019-Sep-26
13.9 LD
8.4
40
2017 KP27
2019-Sep-26
4.2 LD
4.7
25
2006 QV89
2019-Sep-27
18.1 LD
4.1
31
2019 SP
2019-Sep-30
6.7 LD
14.8
46
2018 FK5
2019-Oct-01
13.3 LD
10.5
8
2018 LG4
2019-Oct-02
13.8 LD
8.1
12
2017 TJ4
2019-Oct-05
13.5 LD
8.9
32
2019 RK
2019-Oct-08
16.7 LD
3.1
31
162082
2019-Oct-25
16.2 LD
11.2
589
2017 TG5
2019-Oct-25
14.4 LD
11.9
34
2015 JD1
2019-Nov-03
12.9 LD
11.9
269
2010 JG
2019-Nov-12
19.6 LD
14.9
235
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

SOMETHING NEW! We have developed a new predictive model of aviation radiation. It's called E-RAD--short for Empirical RADiation model. We are constantly flying radiation sensors onboard airplanes over the US and and around the world, so far collecting more than 22,000 gps-tagged radiation measurements. Using this unique dataset, we can predict the dosage on any flight over the USA with an error no worse than 15%.

E-RAD lets us do something new: Every day we monitor approximately 1400 flights criss-crossing the 10 busiest routes in the continental USA. Typically, this includes more than 80,000 passengers per day. E-RAD calculates the radiation exposure for every single flight.

The Hot Flights Table is a daily summary of these calculations. It shows the 5 charter flights with the highest dose rates; the 5 commercial flights with the highest dose rates; 5 commercial flights with near-average dose rates; and the 5 commercial flights with the lowest dose rates. Passengers typically experience dose rates that are 20 to 70 times higher than natural radiation at sea level.

To measure radiation on airplanes, we use the same sensors we fly to the stratosphere onboard Earth to Sky Calculus cosmic ray balloons: neutron bubble chambers and X-ray/gamma-ray Geiger tubes sensitive to energies between 10 keV and 20 MeV. These energies span the range of medical X-ray machines and airport security scanners.

Column definitions: (1) The flight number; (2) The maximum dose rate during the flight, expressed in units of natural radiation at sea level; (3) The maximum altitude of the plane in feet above sea level; (4) Departure city; (5) Arrival city; (6) Duration of the flight.

SPACE WEATHER BALLOON DATA: 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. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Our latest measurements show that cosmic rays are intensifying, with an increase of more than 18% since 2015:

The data points in the graph above correspond to the peak of the Reneger-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.

En route to the stratosphere, our sensors also pass through aviation altitudes:

In this plot, dose rates are expessed as multiples of sea level. For instance, we see that boarding a plane that flies at 25,000 feet exposes passengers to dose rates ~10x higher than sea level. At 40,000 feet, the multiplier is closer to 50x.

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.

Why are cosmic rays intensifying? The main reason is the sun. Solar storm clouds such as coronal mass ejections (CMEs) sweep aside cosmic rays when they pass by Earth. During Solar Maximum, CMEs are abundant and cosmic rays are held at bay. Now, however, the solar cycle is swinging toward Solar Minimum, allowing cosmic rays to return. Another reason could be the weakening of Earth's magnetic field, which helps protect us from deep-space radiation.

  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
NOAA 27-Day Space Weather Forecasts
  fun to read, but should be taken with a grain of salt! Forecasts looking ahead more than a few days are often wrong.
Aurora 30 min forecast
  from the NOAA Space Environment Center
Heliophysics
  the underlying science of space weather

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