Spotless Days Current Stretch: 4 days 2020 total: 126 days (73%) 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 Jun 2020
Thermosphere Climate Index today: 2.68x1010W Cold Max: 49.4x1010 W Hot (10/1957) Min: 2.05x1010W Cold (02/2009) explanation | more data:gfx, txt Updated 20 Jun 2020
Cosmic RaysSolar minimum is underway. The sun's magnetic field is weak, allowing extra cosmic rays into the solar system. Neutron counts from the University of Oulu's Sodankyla Geophysical Observatory show that cosmic rays reaching Earth in 2020 are near a Space Age peak. Oulu Neutron Counts Percentages of the Space Age average: today: +9.6% High 48-hr change: -0.3% Max: +11.7% Very High (12/2009) Min: -32.1% Very Low (06/1991) explanation |more data Updated 20 Jun 2020 @ 1600 UT
Interplanetary Mag. Field Btotal: 2.7 nT Bz: 1.5 nT north more data: ACE, DSCOVR Updated: Today at 2345 UT
Coronal Holes: 20 Jun 20
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA
Noctilucent CloudsNLC season has begun. NASA's AIM spacecraft detected a blue cloud over the north pole on May 17th--one of the earliest starts in the spacecraft's 14 year history. Check here for daily images from AIM.
Geomagnetic Storms: Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2020 Jun 20 2200 UTC
Saturday, Jun. 20, 2020
What's up in space
When the pandemic is over, Marianne Bergli would like to show you something: The Northern Lights. Marianne's team at Heaven on Earth Aurora Tours is eager to see you when flights to Norway resume--perfect for small groups/families.
NOCTILUCENT CLOUDS ARE SPREADING SOUTH: Noctilucent clouds (NLCs) have descended to their lowest latitude of the 2020 season: +44 N in Bend, Oregon. "I woke up at 3:30 am on June 18th to a very bright sky shining through the shades," reports Bend resident Roy Reynolds, who photographed the glowing clouds. NLCs usually descend even lower after the summer solstice--that is, after today. So be alert for electric blue.
'RING OF FIRE' SOLAR ECLIPSE: The sun is about to turn into a "ring of fire." On June 21st, the Moon will pass directly in front of the sun, producing an annular solar eclipse over Earth's eastern hemisphere. Graphic artist Larry Koehn created this animated preview:
Annular eclipses are not total. Only about 99% of the solar disk will be covered. The remainder juts out around the Moon, creating a "ring of fire." The narrow path of annularity stretches from east Africa to the Pacific Ocean, with greatest coverage occurring over the Himalaya of northern India at 06:41 UT.
A partial eclipse, in which a smaller fraction of the sun is covered, can be seen across a much wider area including parts of Europe, the Middle East, India, almost all of Asia, and northernmost Australia. Observers, be careful! A partially eclipsed sun is still dangerously bright and should not be looked at through magnifying optics. Try projection techniques instead.
Because annular eclipses are not, technically, total, they are sometimes considered to be lesser events. Decide for yourself ... after watching this video of an annular eclipse at sunrise over western Australia on May 10, 2013:
Because of the COVID-19 pandemic, many eclipse chasers are "grounded" for this event. However, it is still possible to watch the eclipse thanks to a number of live webcasts: #1, #2, #3.
Photographers in the eastern hemisphere, if you have images of the eclipse, please submit them here!
RARE TRIPLE CONJUNCTION: Yesterday morning (June 19th) in Europe, the crescent Moon eclipsed Venus in broad daylight. About an hour before the occultation began, astronomer Thierry Legault photographed something even more unusual. "The International Space Station (ISS) flew by , creating a 'triple conjunction' with the Moon and Venus," he says.
A resident of France, Legault traveled almost 1000 km to Parma, Italy, to record this rare event. The results were worth the trip. More rare view of the occultation may be found in the Realtime Photo Gallery.
APOLLO 11 PROOF SILVER DOLLAR (COLLECTOR'S ITEM): Are you looking for a far-out gift? Consider this: On July 20, 2019 (the 50th anniversary of the Apollo 11 Moon landing), the students of Earth to Sky Calculus flew this rare proof silver dollar to the stratosphere:
The US Mint created the coins to celebrate the first Moon landing--but you can no longer buy them from the Mint. You can, however, get one from Earth to Sky Calculus. The students are selling the collector's item for $229.95 to support their cosmic ray ballooning program.
The silver dollar is curved and reproduces the helmet of astronaut Buzz Aldrin. Reflected in Buzz's visor are Neil Armstrong, the United States flag, and the lunar lander. The opposite side of the coin shows Neil's iconic footprint on the Moon. Included is a greeting card showing the coin in flight and a certificate of authenticity.
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 June 20, 2020, the network reported 18 fireballs. (18 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 June 20, 2020 there were 2037 potentially hazardous asteroids.
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 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 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.