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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 478.1 km/sec
density: 3.6 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 2350 UT
X-ray Solar Flares
6-hr max: A7
1809 UT Jul31
24-hr: A7
0757 UT Jul31
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 31 Jul 19
The sun is blank--no sunspots. Credit: SDO/HMI

Sunspot number: 0
What is the sunspot number?
Updated 31 Jul 2019

Spotless Days
Current Stretch: 8 days
2019 total: 140 days (66%)
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 31 Jul 2019


Thermosphere Climate Index
today: 2.61
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 31 Jul 2019

The Radio Sun
10.7 cm flux: 66 sfu
explanation | more data
Updated 31 Jul 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: 7.2 nT
Bz: 6.0 nT north
more data: ACE, DSCOVR
Updated: Today at 2348 UT
Coronal Holes: 31 Jul 19


Earth may be entering a stream of solar wind flowing from the indicated coronal hole.
Credit: SDO/AIA

Noctilucent Clouds The northern season for noctilucent clouds is underway. Monitor the daily images from NASA's AIM spacecraft to see how the clouds spread around the Arctic Circle as northern summer unfolds.
Switch view: Europe, USA, Asia, Polar
Updated at: 07-18-2019 14:55:02
SPACE WEATHER
NOAA Forecasts
Updated at: 2019 Jul 31 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 Jul 31 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
10 %
MINOR
05 %
01 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
25 %
20 %
SEVERE
25 %
20 %
 
Wednesday, Jul. 31, 2019
What's up in space
       
 

Special Offer: SAVE 600nok per person. Book a combination aurora borealis chase and scenic day tour during the months of September, October or November 2019 for the special price of 1800 kr. Check Marianne's webpage for details!

 

THE SOLAR WIND HAS ARRIVED: As predicted, a stream of solar wind has reached Earth on July 31st and is gently buffeting our planet's magnetic field. The gaseous material is flowing from a hole in the sun's atmosphere. High-latitude sky watchers should be alert for auroras, especially in the southern hemisphere where winter darkness favors visibility. Aurora alerts: SMS Text.

THE PERSEID METEOR SHOWER IS UNDERWAY: Earth is entering a stream of debris from Comet Swift-Tuttle, source of the annual Perseid meteor shower. Forecasters expect the shower to peak on Aug. 12-13 with many fireballs slicing through the light of a nearly full Moon. It's not even August yet, but NASA's network of all-sky cameras is already detecting a few Perseid fireballs every night--rates which will surely increase in the weeks ahead.

Comet Swift-Tuttle is a giant. It's nucleus is 26 km in diameter, or two-and-a-half times the size of the asteroid that wiped out the dinosaurs. Most other comets are much smaller, with nuclei only a few kilometers across. As a result of its size, Comet Swift-Tuttle produces a large number of meteoroids, many of which are hefty enough to produce fireballs.

Indeed, a 6-year study by NASA's Meteoroid Environment Office found that the Perseids produce more fireballs than any other annual shower:

During the shower, which lasts for weeks, debris particles a few cm wide hit the atmosphere with a speed of 59.6 km/s (133,350 mph). The average magnitude of the resulting fireballs is -3.7, about as bright as Venus.

The luminosity of Perseids is important this year. In 2019 the shower peaks only a few nights before the full Moon, so meteors need to be extra bright to be seen through the glare. Some experts recommend watching a bit earlier than usual, on Aug. 9th, 10th, and 11th when the Moon is less full. The peak nights of Aug. 12th and 13th will be tempered by lunar interference. Whatever night you select, the best time to look is during the hours before sunrise when the shower's radiant is high in the sky. [sky map]

Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter

A GOOD NIGHT FOR GREEN AIRGLOW: Nights around the New Moon are special to astrophotographers. They reveal things normally overwhelmed by moonlight. Last night, Ruslan Merzlyakov saw one of those things over Denmark--ripples of green airglow:

"The sky was filled with green airglow," says Merzlyakov. "It crissed-crossed the Milky Way above the island of Møn."

Airglow looks like the aurora borealis, but it is not the same. Airglow is caused by a complex assortment of chemical reactions in Earth's upper atmosphere. These reactions get started during daylight hours when the atmosphere is bathed in strong UV radiation from the sun.  At night we see the afterglow, colored green by oxygen atoms 90-100 km high or sometimes red by hydroxyl ions 86-87 km high.

"The airglow was corrugated by gravity waves propagating upward from a nearby thunderstorm," adds  Merzlyakov.  This phenomenon is quite common during the season for summer storms, and gives most airglow a dramatic rippling structure.

"Now I can't wait for the first Perseids!" he says.

THE STARSHIP ENTERPRISE IN THE STRATOSPHERE: Last week, the students of Earth to Sky Calculus launched the starship Enterprise to the stratosphere. Riding onboard a high-altitude cosmic ray balloon, the laser-etched crystal spaceship traveled 34.7 km (113,845 feet) above Earth's surface:

You can have it for $149.95. The students are selling the Enterprise to support their cosmic ray ballooning program. Each starship comes with a greeting card showing the item in flight and telling the story of its journey to the edge of space. Also included is a multi-colored LED illuminated stand (shown in the picture above). This creates a colorful visual effect and allows the Enterprise to be used as a far-out night light.

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


Realtime Aurora 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 Jul. 31, 2019, the network reported 36 fireballs.
(25 sporadics, 7 Southern delta Aquariids, 3 Perseids, 1 alpha Capricornid)

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 July 31, 2019 there were 1983 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Velocity (km/s)
Diameter (m)
2010 PK9
2019-Jul-26
8.2 LD
16.5
155
2019 NT1
2019-Jul-27
19 LD
3.7
14
2019 OD3
2019-Jul-28
0.5 LD
18.1
15
2019 OM3
2019-Jul-28
2.6 LD
12.8
18
2019 OB1
2019-Jul-28
2 LD
6.9
9
2019 ON3
2019-Jul-29
0.6 LD
14.2
10
2019 NN4
2019-Jul-29
6.6 LD
3.8
26
2019 ON
2019-Aug-01
6.8 LD
4.7
33
2019 OJ3
2019-Aug-02
11.4 LD
16.2
60
2006 QQ23
2019-Aug-10
19.4 LD
4.7
339
454094
2019-Aug-12
17 LD
8.2
148
2018 PN22
2019-Aug-17
17.1 LD
2.3
11
2016 PD1
2019-Aug-26
11.4 LD
5.9
65
2002 JR100
2019-Aug-27
19.4 LD
8.4
49
2019 OU1
2019-Aug-28
2.7 LD
13.2
92
2019 OF2
2019-Sep-03
18 LD
10.5
49
2018 DE1
2019-Sep-03
12.7 LD
6.6
28
2019 GT3
2019-Sep-06
19.5 LD
13.6
227
2010 RM82
2019-Sep-13
18.2 LD
14.6
23
2013 CV83
2019-Sep-13
15.7 LD
13.1
62
504800
2019-Sep-14
13.9 LD
14.4
155
467317
2019-Sep-14
13.9 LD
6.4
389
2019 JF1
2019-Sep-16
11.2 LD
4.3
61
2018 FU1
2019-Sep-16
18.4 LD
4.7
16
2017 SL16
2019-Sep-21
7.9 LD
6.5
25
2017 SM21
2019-Sep-21
11.5 LD
9.6
20
2006 QV89
2019-Sep-23
15.9 LD
4.2
31
523934
2019-Sep-24
10.9 LD
22.3
257
2017 KP27
2019-Sep-26
6.2 LD
4.8
25
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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