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SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids
 
Solar wind
speed: 383.0 km/sec
density: 3.3 protons/cm3
more data: ACE, DSCOVR
Updated: Today at 2346 UT
X-ray Solar Flares
6-hr max: A6
1817 UT Sep25
24-hr: A7
0323 UT Sep25
explanation | more data
Updated: Today at: 2300 UT
Daily Sun: 25 Sep 19
The sun is blank--no sunspots. Credit: SDO/HMI

Sunspot number: 0
What is the sunspot number?
Updated 25 Sep 2019

Spotless Days
Current Stretch: 22 days
2019 total: 193 days (72%)
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 25 Sep 2019


Thermosphere Climate Index
today: 4.28
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 25 Sep 2019

The Radio Sun
10.7 cm flux: 67 sfu
explanation | more data
Updated 25 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= 2
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 4.6 nT
Bz: -1.7 nT south
more data: ACE, DSCOVR
Updated: Today at 2346 UT
Coronal Holes: 25 Sep 19


Solar wind flowing from this large coronal hole should reach Earth on Sept. 27-28.
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 25 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 25 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
20 %
30 %
MINOR
05 %
35 %
SEVERE
01 %
20 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
20 %
05 %
MINOR
30 %
20 %
SEVERE
25 %
65 %
 
Wednesday, Sep. 25, 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!

 

GEOMAGNETIC STORM WARNING: A large hole in the sun's atmosphere is facing Earth and spewing solar wind in our direction. Estimated time of arrival: Sept. 27-28. NOAA forecasters say G1- to G2-class geomagnetic storms are possible when the gaseous material arrives. Aurora alerts: SMS Text.

A SUMMER WITHOUT SUNSPOTS: Could northern summer 2019 go down in history as "the summer without sunspots"? From June 21st until Sept 22nd, the sun was blank more than 89% of the time. During the entire season only 6 tiny sunspots briefly appeared, often fading so quickly that readers would complain to Spaceweather.com, "you've labeled a sunspot that doesn't exist!" (No, it just disappeared.) Not a single significant solar flare was detected during this period of extreme quiet.


The sun on Sept. 22, 2019--as blank as a billiard ball. Credit: NASA/SDO

This is a sign that Solar Minimum is underway and probably near its deepest point. For 2019 overall (January through September), the sun has been blank 72% of the time, comparable to annual averages during the century-class Solar Minimum of 2008 (73%) and 2009 (71%). The current Solar Minimum appears to be century-class as well, meaning you have to go back to the beginning of the 20th century to find lulls in solar activity this deep.

Contrary to the sound of it, "Solar Minimum" is not boring. During this phase of the solar cycle, the sun's magnetic field weakens, allowing cosmic rays to enter the solar system. This doses astronauts and possibly air travelers with extra radiation. The sun also dims, especially at extreme ultraviolet wavelengths, causing the upper atmosphere to cool and collapse. Space junk accumulates in Earth orbit as a result. Finally, streams of solar wind punch through the sun's weakening magnetic field, lashing Earth with gaseous material that can cause geomagnetic storms. (One such stream is due later this week on Sept. 27-28.)

Interestingly, the summer of 2019 also brought us a sign that Solar Minimum is coming to an end. One of the numbered sunspots that briefly appeared on July 7th had a reversed magnetic polarity:


A magnetic map of the sun's surface (AR2744 inset) from NASA's Solar Dynamics Observatory

According to Hale's Law, sunspots switch polarities from one solar cycle to the next. This small summertime sunspot was +/- instead of the usual -/+, marking it as a member of the next solar cycle, Solar Cycle 25. Solar Minimum won't last forever!

Solar cycles always mix together at their boundaries. We can expect to see more new-cycle sunspots in the months ahead as Solar Cycle 24 dies out and Solar Cycle 25 slowly comes to life. If forecasters are correct, the next Solar Maximum will be in full swing by 2023.

Realtime Aurora Photo Gallery
Free:
Spaceweather.com Newsletter

PURPLE HEART SPACE PENDANT: Nothing says "I Love You" like a heart-shaped pendant from the edge of space. Last week, the students of Earth to Sky Calculus flew an array of cosmic ray sensors to the stratosphere onboard a giant helium balloon. This purple heart went along for the ride:

You can have it for $129.95. The students are selling these pendants as a fund-raiser for their cosmic ray monitoring program. They make great anniversary, birthday and Christmas gifts. Each pendant comes with a greeting card showing the jewelry in flight and telling the story of its journey to the stratosphere and back again.

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. 25, 2019, the network reported 31 fireballs.
(31 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 25, 2019 there were 2018 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Velocity (km/s)
Diameter (m)
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
2019 SU2
2019-Sep-21
0.2 LD
11.9
4
2017 SM21
2019-Sep-21
11.5 LD
9.6
20
2019 SD1
2019-Sep-21
0.7 LD
24.1
7
2019 SS2
2019-Sep-21
0.3 LD
8.8
3
2019 RE2
2019-Sep-21
19.7 LD
8.7
43
2019 SR2
2019-Sep-21
17.4 LD
8.3
29
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 SW1
2019-Sep-24
3 LD
12.7
13
2019 QY3
2019-Sep-26
13.9 LD
8.4
40
2019 SP2
2019-Sep-26
5.7 LD
9.4
59
2017 KP27
2019-Sep-26
4.2 LD
4.7
25
2006 QV89
2019-Sep-27
18.1 LD
4.1
31
2019 SO1
2019-Sep-29
11.3 LD
7.5
16
2019 SH3
2019-Sep-30
3.1 LD
14.1
24
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
30
2019 SE2
2019-Oct-12
19.3 LD
10.2
55
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
481394
2019-Nov-21
11.3 LD
7.9
372
2008 EA9
2019-Nov-23
10.5 LD
2.2
10
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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