Spotless Days Current Stretch: 0 days 2019 total: 109 days (61%) 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 28 Jun 2019
Thermosphere Climate Index today: 3.48x1010W Cold Max: 49.4x1010 W Hot (10/1957) Min: 2.05x1010W Cold (02/2009) explanation | more data Updated 28 Jun 2019
Interplanetary Mag. Field Btotal: 4.6 nT Bz: -0.5 nT south more data: ACE, DSCOVR Updated: Today at 2347 UT
Coronal Holes: 28 Jun 19
Solar wind flowing from this coronal hole could reach Earth on July 3rd or 4th. Credit: SDO/AIA
Noctilucent CloudsThe northern season for noctilicent 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.
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 Jun 28 2200 UTC
Friday, Jun. 28, 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!
NASA TO SEND HELICOPTER TO ANOTHER PLANET: This could be NASA's most exciting mission--ever. The space agency announced yesterday that they will send a heliocopter to Titan, Saturn's largest moon. Titan is in many ways more like Earth than any other place in the solar system. It has rivers and lakes, a thick atmosphere, and organic compounds that could support the genesis of life. The quad-chopper, named "Dragonfly," will fly between sites on interest, covering more than twice the distance of every Mars rover combined. Get the full story from nasa.gov.
RARE SUNSET ECLIPSE OF THE SUN: Residents of Chile and Argentina are about to witness a rare total eclipse of the sun. On July 2, 2019, the new Moon will pass across the solar disk, creating a black hole in the sky just before sunset in the two South American countries. This animated map, created by space artist Larry Koehn, includes a detailed local timetable of events:
The path of totality cuts across ESO's La Silla Observatory in Chile and barely misses the center of Buenos Aires in Argentina. The Moon's elongated sunset shadow will swallow observers for 1 to 2 minutes depending on their exact location.
Outside the path of totality, the eclipse is partial with significant coverage in large cities such as Santiago, Chile (93%); Montevideo, Uruguay (94%); La Paz, Bolivia (63%); and Lima, Peru (54%). During the partial phase of the eclipse, the sun looks like a crescent, and it casts crescent-shaped shadows on the ground. South Americans should look for them underneath the canopies of leafy trees. Using safe eclipse glasses, it is possible to view the crescent sun directly.
The sun and Moon align for an eclipse once or twice every year. Aligning directly over a major observatory, however, is very rare. This video shows what the eclipse will look like over La Silla:
La Silla is home to some of the world's biggest telescopes and many skilled observers. Observatory staff will host more than a thousand members of the public in a viewing party among the telescope domes. A live high-definition webcast of the eclipse will be available on ESO's website and on ESO's Youtube Channel. The action begins on Tuesday, July 2nd. Stay tuned!
APOLLO 11 PROOF SILVER DOLLAR To celebrate the 50th anniversary of the Apollo 11 Moon landing, the United States Mint has created a commemorative 2019 Proof Silver Dollar. We decided to celebrate even more by flying the coins to the edge of space. On June 23rd, the students of Earth to Sky Calculus launched this 99.9% silver dollar 102,034 feet above Earth's surface:
You can have it for $197.95. The students are selling the coins 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. Each of these coins comes with a greeting card showing the item in flight and a certificate of authenticity.
A NEW SPACE WEATHER SPACECRAFT: There's a new spacecraft in Earth orbit, and it's going where few spacecraft have gone before. Launched by SpaceX on June 25th, DSX is on a mission to explore the gap between the two Van Allen Radiation Belts. Last night, DSX passed over the home of amateur astronomer Scott Tilley in British Columbia, and he received a loud S-band radio transmission:
"A great signal from a spacecraft 8000 km away!" says Tilley, who is famous for tracking and finding satellites using their radio transmissions. "Based on the timing and Doppler shift of the signal, DSX appears to have reached its proper orbit."
DSX is now circling Earth in a region once thought to be safe--but maybe not. Earth is surrounded by two radiation belts seething with energetic particles. The gap between those belts, called the "slot region," is usually empty. In 2013, NASA spacecraft discovered that's not always so. During some solar storms, it can flood with radiation from the adjacent belts, sometimes forming a third belt. How much the slot region changes, and how quickly, remains uncertain.
"There haven't been too many measurements to tell us how bad things get in the slot region," says Michael Xapsos of NASA's Goddard Space Flight Center. "That's why we're going there."
DSX will investigate conditions in the slot region using a variety of onboard sensors and experiments. NASA's tagalong SET experiment, for instance, will expose sample circuit boards to the environment, monitoring accumulated damage to see what might happen to computers on future spacecraft. Another experiment, WPIx, is even more interesting. It will study wave-particle interactions to discover if VLF (very low frequency) radio signals transmitted from Earth could be used to control or eliminate particles in the slot region.
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 Jun. 28, 2019, the network reported 46 fireballs. (44 sporadics, 1 Daytime beta Taurid, 1 Northern June Aquilid)
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 28, 2019 there were 1983 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.