SpaceWeather.com -- News and information about meteor showers, solar flares, auroras, and near-Earth asteroids

Solar wind
speed: 530.8 km/sec
density: 3.32 protons/cm³
more data: ACE, DSCOVR
Updated: Today at 0446 UT

X-ray Solar Flares
6-hr max: C2 1310 UT May20
24-hr: C5 0554 UT May20
explanation | more data
Updated: Today at: 1650 UT

Daily Sun: 20 May 25

Expand: labels | no labels

Sunspot 4087 is decaying and no longer poses a significant threat for X-class solar flares. NASA/SDO

Sunspot number: 66
What is the sunspot number?
Updated 20 May 2025

Spotless Days
Current Stretch: 0 days
2025 total: 0 days (0%)
2024 total: 0 days (0%)
2023 total: 0 days (0%)
2022 total: 1 day (<1%)
2021 total: 64 days (18%)
2020 total: 208 days (57%)
2019 total: 281 days (77%)
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 20 May 2025

Thermosphere Climate Index
today: 23.61x10¹⁰ W Warm
Max: 49.4x10¹⁰ W Hot (10/1957)
Min: 2.05x10¹⁰ W Cold (02/2009)
explanation | more data: gfx, txt
Updated 19 May 2025

The Radio Sun
10.7 cm flux: 117 sfu
explanation | more data
Updated 20 May 2025

Cosmic Rays Solar Cycle 25 is intensifying, and this is reflected in the number of cosmic rays entering Earth's atmosphere. Neutron counts from the University of Oulu's Sodankyla Geophysical Observatory show that cosmic rays reaching Earth are slowly declining--a result of the yin-yang relationship between the solar cycle and cosmic rays.

Oulu Neutron Counts
Percentages of the Space Age average:
today: -5.6% Low
48-hr change: -0.2%
Max: +11.7% Very High (12/2009)
Min: -32.1% Very Low (06/1991)
explanation | more data
Updated 20 May 2025 @ 0700 UT

Current Auroral Oval:

Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation

Planetary K-index
Now: Kp= 3.00 quiet
24-hr max: Kp= 3.00 quiet
explanation | more data

Interplanetary Mag. Field
B_total: 9.29 nT
B_z: -2.54 nT south
more data: ACE, DSCOVR
Updated: Today at 0446 UT

Coronal Holes: 20 May 25

Solar wind flowing from this large southern coronal hole should reach Earth on May 20-21. Credit: NASA/SDO | more data

Polar Stratospheric Clouds
Colorful Type II polar stratospheric clouds (PSC) form when the temperature in the stratosphere drops to a staggeringly low -85C. NASA's MERRA-2 climate model predicts when the air up there is cold enough:

On May 20, 2025, the Arctic stratosphere is much too hot for polar stratospheric clouds. | more data.

Noctilucent Clouds
The southern season for noctilucent clouds (NLCs) is finished. The first clouds were detected over Antarctica on Nov. 19, 2024, and they vanished again on Feb. 21, 2025. The action will shift to the north pole in late May 2025. Until then, the map will remain blank.

Updated: Feb. 21, 2025
An instrument onboard NOAA 21 (OMPS LP) is able to detect NLCs (also known as "polar mesospheric clouds" or PMCs). In the daily map, above, each dot is a detected cloud. As the season progresses, these dots will multiply in number and shift in hue from blue to red as the brightness of the clouds intensifies.

SPACE WEATHER
NOAA Forecasts

Updated at: 2025 May 19 2200 UTC

FLARE	0-24 hr	24-48 hr
CLASS M	35 %	35 %
CLASS X	05 %	05 %

Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm

Updated at: 2025 May 19 2200 UTC

Mid-latitudes

	0-24 hr	24-48 hr
ACTIVE	30 %	30 %
MINOR	15 %	15 %
SEVERE	01 %	01 %

High latitudes

	0-24 hr	24-48 hr
ACTIVE	15 %	15 %
MINOR	30 %	30 %
SEVERE	45 %	45 %


		Tuesday, May. 20, 2025
	What's up in space	Tuesday, May. 20, 2025

This is an AI Free Zone: AI isn't all bad. Large language models are good writers with access to vast stores of data. There's still no substitute for a human being with decades of space weather forecasting experience. This website is 100% human.

POSSIBLE GLANCING-BLOW CME THIS WEEK: Yesterday, a magnetic filament lifted off the sun's northern hemisphere and hurled a CME into space. NOAA forecasters say it could deliver a glancing blow to Earth's magnetic field on May 23rd. If so, the impact would increase already existing odds of a G1-class geomagnetic storm. See below. Aurora alerts: SMS Text

A BIG HOLE IN THE SUN'S ATMOSPHERE: Minor G1-class geomagnetic storms are possible for the next 3 days (May 20-22) as Earth passes through a stream of solar wind. The gaseous material is flowing from a hole in the sun's atmosphere, which stretches across most of the sun's southern hemisphere. The million-kilometer-wide structure is shown in this extreme ultraviolet image from NASA's Solar Dynamics Observatory:

This is a "coronal hole"--a region in the sun's atmosphere where magnetic fields have opened up, allowing solar wind to escape. Coronal holes look dark because hot glowing gas normally contained there is missing. In this case, it is en route to Earth.

We've seen this coronal hole before--approximately every 28 days since February. Here it is in March, and again in April. It has been spinning around with the sun, emitting a stream of material akin to a giant lawn sprinkler. The stream encounter was particularly effective in March when it sparked auroras across many northern-tier US states. Aurora alerts: SMS Text

Realtime Aurora Photo Gallery
Free: Spaceweather.com Newsletter

JALAPEñO PEPPERS FROM SPACE: These are the first Jalapeño seeds ever flown to the edge of space. On May 14, 2025, the students of Earth to Sky Calculus launched them onboard a cosmic ray research balloon. They spent 3 hours in the stratosphere exposed to Mars-like temperatures (-62 C) and cosmic rays:

You can have them for $99.95. Also included are packets of Cayenne, Cubanelle, Orange Habanero ... 10 varieties in all. These seeds make a great DIY science project. Each space-flown packet of seeds comes with an identical control packet, which remained on Earth during the flight. Plant them side by side to discover the difference space travel makes.

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

Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter

Realtime Comet 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 May 19, 2025, the network reported 4 fireballs.
(4 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 May 20, 2025 there were 2349 potentially hazardous asteroids.

Recent & Upcoming Earth-asteroid encounters:

Asteroid	Date(UT)	Miss Distance	Velocity (km/s)	Diameter (m)
2025 DT50	2025-May-14	16 LD	6.4	105
2025 HD19	2025-May-17	7.3 LD	9	28
2025 KA	2025-May-17	4.2 LD	11.8	23
2025 KD	2025-May-18	3.6 LD	6.7	25
2008 ST	2025-May-20	13.5 LD	2.5	14
2025 JE1	2025-May-20	11.4 LD	1.4	23
2025 KC	2025-May-23	2.7 LD	7.5	17
387746	2025-May-24	17.4 LD	8.3	339
2014 KF22	2025-May-25	9.1 LD	11.5	19
390725	2025-May-25	18.4 LD	13.5	410
2025 JP	2025-May-27	13.4 LD	7	25
2025 JR	2025-May-28	12.1 LD	11.3	76
2025 FU5	2025-May-28	13.4 LD	7.3	92
2022 KP3	2025-May-30	10.2 LD	7.7	7
424482	2025-Jun-05	9.1 LD	6.2	421
2020 LQ	2025-Jun-06	17.3 LD	11.8	34
2018 LE4	2025-Jun-07	12.2 LD	13.3	62
2014 LL26	2025-Jun-08	8 LD	5.2	31
2022 KQ5	2025-Jun-12	13.6 LD	5.1	5
2023 XO15	2025-Jun-15	17.8 LD	3.4	24
2025 HN6	2025-Jun-16	6.4 LD	2.3	24
2000 LF3	2025-Jun-17	18.9 LD	14.5	169
2023 XU2	2025-Jun-18	11.1 LD	15.6	32
2003 AY2	2025-Jun-22	14.2 LD	15.9	386
2014 DH	2025-Jun-28	17.1 LD	12.1	17
2019 JM	2025-Jul-09	16.6 LD	6.9	14
2019 NW5	2025-Jul-09	15.2 LD	16.5	65
2005 VO5	2025-Jul-11	15.9 LD	14.4	382
2022 YS5	2025-Jul-17	17.4 LD	6.1	38

Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU.

Cosmic Rays in the Atmosphere

SPACE WEATHER BALLOON DATA: Almost 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 sensors that detect secondary cosmic rays, a form of radiation from space that can penetrate all the way down to Earth's surface. Our monitoring program has been underway without interruption for 10 years, resulting in a unique dataset of in situ atmospheric measurements.

Latest results (Nov. 2024): Atmospheric radiation is sharply decreasing in 2024. Our latest measurements in November registered a 10-year low:

What's going on? Ironically, the radiation drop is caused by increasing solar activity. Solar Cycle 25 has roared to life faster than forecasters expected. The sun's strengthening and increasingly tangled magnetic field repels cosmic rays from deep space. In addition, solar coronal mass ejections (CMEs) sweep aside cosmic rays, causing sharp reductions called "Forbush Decreases." The two effects blend together to bring daily radiation levels down.

.Who cares? Cosmic rays are a surprisingly "down to Earth" form of space weather. They can alter the chemistry of the atmosphere, trigger lightning, and penetrate commercial airplanes. According to a study from the Harvard T.H. Chan school of public health, crews of aircraft have higher rates of cancer than the general population. The researchers listed cosmic rays, irregular sleep habits, and chemical contaminants as leading risk factors. A number of controversial studies (#1, #2, #3, #4) go even further, linking cosmic rays with cardiac arrhythmias and sudden cardiac death.

Technical notes: 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.

Data points in the graph labeled "Stratospheric Radiation" correspond to the peak of the Regener-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 Regener and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.

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.

SolarMonitor.org

information about sunspots based on the latest NOAA/USAF Active Region Summary

Starlink Satellite Statistics

current counts of failed and deployed Starlink satellites from Jonathan's Space Page. See also, all satellite statistics.

The Aerospace Corporation

Authoritative predictions of space junk and satellite re-entries

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

Live Aurora Webcam

from Lights over Lapland

Heliophysics

the underlying science of space weather

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T CrB NOVA WATCH
today: m=10.6 (May 20.5)
yesterday: m=10.1
more: AAVSO data

Explanation: When the nova explodes, the visual magnitude of the star (m) will jump from +10 (invisible to the naked eye) to +2 (about as bright as the North Star).