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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 413.5 km/sec
density: 6.7 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 2350 UT
X-ray Solar Flares
6-hr max: A7
1740 UT Apr23
24-hr: A7
1100 UT Apr23
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 23 Apr 19
The sun is blank -- no sunspots. Credit: SDO/HMI

Sunspot number: 0
What is the sunspot number?
Updated 23 Apr 2019

Spotless Days
Current Stretch: 2 days
2019 total: 64 days (57%)
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 23 Apr 2019


Thermosphere Climate Index
today: 4.33
x1010 W Cold
Max: 49.4
x1010 W Hot (10/1957)
Min: 2.05
x1010 W Cold (02/2009)
explanation | more data
Updated 23 Apr 2019

The Radio Sun
10.7 cm flux: 69 sfu
explanation | more data
Updated 23 Apr 2019

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
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 6.2 nT
Bz: -2.8 nT south
more data: ACE, DSCOVR
Updated: Today at 2349 UT
Coronal Holes: 23 Apr 19


Solar wind flowing from this southern coronal hole could reach Earth's magnetic field on April 24-25, causing polar geomagnetic unrest.
Credit: SDO/AIA

Noctilucent Clouds The northern season for noctilicent clouds is little more than a month away. The electric-blue clouds circling the north pole should return in mid- to late May. .
Switch view: Europe, USA, Asia, Polar
Updated at: 03-02-2019 16:55:03
SPACE WEATHER
NOAA Forecasts
Updated at: 2019 Apr 23 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 Apr 23 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
25 %
MINOR
05 %
10 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
20 %
15 %
MINOR
20 %
30 %
SEVERE
20 %
30 %
 
Tuesday, Apr. 23, 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!

 

SOLAR WIND, INCOMING: A southern hole in the sun's atmosphere is spewing a stream of solar wind toward Earth. Minor geomagnetic storms are possible when the gaseous material arrives on April 24-25. NASA's STEREO-A spacecraft has already encountered the solar wind stream and measured its velocity: Between 500 and 600 km/s. Polar auroras may be seen despite waning full moonlight. Aurora alerts: SMS Text.

RECTANGULAR SUNSET: Everyone knows the sun is round. But when Liselotte Kahns photographed the sunset from Vendsyssel, Denmark on April 19th, the shape was definitely rectangular:

"This is a mock mirage sunset caused by temperature inversions," explains atmospheric optics expert Les Cowley. "These inversions can slice the sun, producing multiple images with some rising and some descending. Sometimes they look rectangular."

There's a more extreme version of this called the "Novaya Zemlya" mirage. Observed near the poles, severe temperature inversions can channel the sun's rays all the way around the curvature of the Earth. "In the Novaya Zemlya mirage, the sun looks rectangular and rises minutes early or sets many minutes late," says Cowley. "Liselotte's mirage is not a Novaya Zemlya," but it's the next best thing outside the Arctic Circle.

Realtime Space Weather Photo Gallery

MOTHER'S DAY IS ONLY 3 WEEKS AWAY! Approximately once a week, the students of Earth to Sky Calculus launch a cosmic ray balloon. To help pay their helium bill, they've flown a payload of Northern Light pendants to the edge of space. This one reached an altitude 109,908 feet above Earth's surface:

Northern Lights pendants make great Mother's Day gifts, and you can have one for $99.95. Each pendant comes with a greeting card showing the item in flight and telling the story of its journey to the edge of space. All sales support the Earth to Sky Calculus cosmic ray ballooning program and hands-on STEM research.

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


Free: Spaceweather.com Newsletter

Realtime Aurora 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. 23, 2019, the network reported 51 fireballs.
(30 sporadics, 21 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, 2019 there were 1967 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Velocity (km/s)
Diameter (m)
2019 GC6
2019-Apr-18
0.6 LD
5.6
18
2012 XO134
2019-Apr-18
14.8 LD
11
56
2019 FN2
2019-Apr-18
4.1 LD
7.7
65
522684
2019-Apr-19
19 LD
11.5
214
2019 HE
2019-Apr-20
0.6 LD
12.2
17
2019 GZ3
2019-Apr-20
10.1 LD
14.2
23
2019 GM
2019-Apr-21
19.4 LD
10.4
35
2019 FV2
2019-Apr-22
15.6 LD
2.3
33
2019 GM4
2019-Apr-23
9.1 LD
8.4
71
2019 GF1
2019-Apr-27
4.7 LD
1.9
11
2019 GX5
2019-Apr-28
7.2 LD
10.7
26
2018 KK1
2019-May-05
13.9 LD
13.9
71
2017 RC
2019-May-09
14.5 LD
10.6
9
2008 HS3
2019-May-09
14.6 LD
5.3
162
2018 VX8
2019-May-12
6.2 LD
15.5
118
2019 GT1
2019-May-17
6.1 LD
3.9
36
2012 KT12
2019-May-18
3.3 LD
3.9
20
2015 KQ18
2019-May-25
10.7 LD
13.1
30
66391
2019-May-25
13.5 LD
21.5
1780
2003 LH
2019-May-28
15.6 LD
7.4
32
2011 HP
2019-May-30
12.3 LD
8.4
135
2014 MF18
2019-Jun-06
8.8 LD
3
22
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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