Spotless Days Current Stretch: 0 days
2019 total: 14 days (64%)
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 22 Jan 2019
Thermosphere Climate Index
today: 3.18x1010W Cold
Max: 49.4x1010 W Hot (10/1957)
Min: 2.05x1010W Cold (02/2009) explanation | more
Updated 22 Jan 2019
Geomagnetic Storms: Probabilities for significant
disturbances in Earth's magnetic field are given for three activity levels: active, minor
Updated at: 2019 Jan 22 2200 UTC
Wednesday, Jan. 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!
CHANCE OF STORMS: NOAA forecasters say there is a 60% chance of G1-class geomagnetic storms on Jan. 24th when a stream of solar wind is expected to hit Earth's magnetic field. The gaseous material is flowing ~600 km/s from a hole in the sun's atmosphere. Arctic auroras are likely this Thursday. Aurora Alerts:SMS text, email.
A METEOROID HITS THE MOON DURING LUNAR ECLIPSE: On Jan. 21st at 04:41:43 UT, a meteoroid slammed into the Moon. We know this because many amateur astronomers witnessed or photographed the explosion. Petr Horálek was one of them; he captured the fireball from Boa Vista, one of the islands of Cape Verde:
"As I was sorting through my pictures of the eclipse, I was trying to avoid images with dusty specks or hot pixels," says Horálek. "Upon closer inspection, I realized this was no hot pixel. It was a flash of light on the Moon--and other astronomers had photographed it as well."
At least a dozen reliable still images and videos of the impact have surfaced so far. Analyzing a sharp image taken by Christian Fröschlin of the Netherlands, geologist and amateur astronomer Justin Cowart has estimated the selenographic coordinates of the impact site: 29.47S, 67.77W +/- 4km. This puts it just to the west of the lunar crater Lagrange H. NASA's Lunar Reconnaissance Orbiter may be able to use such coordinates to target its cameras and photograph the crater.
Meteoroids hit the Moon all the time. Literally. NASA has been observing the impact flashes since 2005. Recently, other groups in Europe have joined the hunt. Flashes are typically observed once every 2 or 3 hours of observing time. Impactors range in size from softballs to boulders, liberating energies equal to tons of TNT when they strike.
Spain's MIDAS survey recorded this video of the Jan 21st lunar meteor strike
The rare thing about this strike is that it was photographed during a full Moon, when lunar glare usually overwhelms the glow of any fireball. During the eclipse, Earth's shadow turned lunar day into almost-night for an hour, allowing the fireball to be seen.
Readers, were you taking pictures of the eclipse around 04:41 UT? Inspect your images! You might have captured an explosion. Submit your images here.
FULL MOON VALENTINE'S GIFT: Poets, lovers, and artists have long known this simple truth: Nothing is more romantic than a full Moon. Now you can give the full Moon as a Valentine's Gift--the full Moon space pendant, that is. This one flew to the stratosphere on Dec. 26, 2018, onboard an Earth to Sky Calculus cosmic ray balloon:
You can have it for $119.95. The students are selling these spherical glass pendants to support their cosmic ray ballooning program. Each one comes with a Valentine's card showing the pendant in flight and telling the story of its journey to the edge of space and back again.
THE BLUE LUNAR ECLIPSE: Lunar eclipses are supposed to be red, yet when the Moon passed through Earth's ruddy shadow on Jan. 20th, many observers witnessed a different color: turquoise blue. Heiko Ulbricht and Dirk Landrock photographed the phenomenon from Radebeul, Germany:
"The colors were wonderful--red and blue," says Ulbricht.
The source of the turquoise is ozone. Prof. Richard Keen, an atmospheric scientist from the University of Colorado explains: "During a lunar eclipse, most of the light illuminating the Moon passes through the stratosphere, and is reddened by scattering. However, light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer." This can be seen, he says, as a turquoise fringe around the red.
Blue appears during every total eclipse of the Moon. Naked-eye observers often miss it because it is fleeting, best seen only during the opening and closing minutes of totality. Binoculars and telescopes improves visibility. "We used a 14-inch Maksutov-Newton telescope," notes Ulbricht.
Every night, a network
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 Jan. 21, 2019, the network reported 10 fireballs.
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]
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 January 23, 2019 there were 1947 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 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.