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HUGE BLUE CLOUD CIRCLES THE NORTH POLE: A huge blue cloud of frosted meteor smoke is pinwheeling around the Arctic Circle. NASA's AIM spacecraft spotted its formation on May 20th, and it has since circled the North Pole one and a half times, expanding in size more than 200-fold.
"These are noctilucent clouds," says Cora Randall of the AIM science team at the University of Colorado. "And they are going strong."
Noctilucent clouds (NLCs) in May are nothing unusual. They form every year around this time when the first wisps of summertime water vapor rise to the top of Earth's atmosphere. Molecules of H2O adhere to specks of meteor smoke, forming ice crystals 80 km above Earth's surface. When sunbeams hit those crystals, they glow electric-blue.
But these NLCs are different. They're unusually strong and congregated in a coherent spinning mass, instead of spreading as usual all across the polar cap.
"This is most likely a sign of planetary wave activity," says Randall.
Planetary waves are enormous ripples of temperature and pressure that form in Earth's atmosphere in response to Coriolis forces. They are responsible in part for undulations in the jet stream and can have a major influence on global weather. All rotating planets with atmospheres have these kind of waves.
Data from NASA's Microwave Limb Sounder (MLS) instruments show that, indeed, a planetary wave is circling the North Pole in sync with the blue cloud:
"The region of coldest temperatures migrates clockwise around the hemisphere, making one complete lap in about 5 days," notes Lynn Harvey of the AIM science team who processed the data. "This is where the NLCs are forming."
Because of planetary wave activity, the 2019 season is shaping up to be unusually good. The clouds have already made an appearance in the USA–something that usually doesn't happen until late June or July.
"Last night, I took my dog out an hour and twenty minutes after sunset and was happily surprised to see these noctilucent clouds," reports Shelley Johnson of Anacortes, Washington, who took this picture on May 30th:
NLCs have also been sighted in Europe–highlighted by a bright display in Germany. "This is my earliest observation of noctilucent clouds and, considering the fact that it's only May, they were exceptionally bright and well structured," reports Laura Kranich of Kiel, Germany. "Seems like this is going to become a great season!"
If the 2019 NLC season continues to develop this quickly, even mid-latitude observers may soon be seeing this polar phenomenon. Observing tips: Look west 30 to 60 minutes after sunset when the sun has dipped below the horizon. If you see luminous blue-white tendrils spreading across the sky, you may have spotted a noctilucent cloud.
Realtime Noctilucent Cloud Photo Gallery
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FISHING IN THE STRATOSPHERE: Father's Day is less than 3 weeks away. Just in time for giftgiving, we present the first fishing lure in space. This unique hook, inscribed with the message "I love you more than you love fishing," hitched a ride onboard an Earth to Sky Calculus cosmic ray balloon on May 17, 2019, reaching an altitude of 117,454 feet:
You can have it for $99.95. The students are selling these lures to support their cosmic ray ballooning program--an increasing necessity because of the worldwide helium shortage. Each hook comes with a greeting card showing the item in flight and telling the story of its journey to the edge of space and back.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
MAMMATUS CLOUDS OVER SAO PAULO: It is a curious fact of Nature that the underbelly of an exhausted thunderstorm resembles the underbelly of a cow. These are called "mammatus clouds":
Willian Souza took the picture yesterday in Sao Paulo, Brazil--"just after sunset," he says. It was once thought that this type of cloud signaled the approach of bad weather, but research shows the opposite is true. Mammatus clouds are most often seen when storms are breaking up. Indeed, the Sao Paulo display came at the end of a thunderstormy day.
What exactly causes mammatus clouds? It's a big undulating mystery. For details, see "The Mysteries of Mammatus Clouds," D. M. Schultz et al, Journal of the Atmospheric Sciences, Volume 63, Issue 10 (October 2006).
Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter
Realtime Aurora Photo Gallery
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. 31, 2019, the network reported 17 fireballs.
(17 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]
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 31, 2019 there were 1983 potentially hazardous asteroids.
|
Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
2019 KK3 | 2019-May-26 | 8.5 LD | 4.5 | 16 |
2019 JD8 | 2019-May-26 | 14.8 LD | 15.1 | 43 |
2019 KN | 2019-May-26 | 4 LD | 10.3 | 23 |
2019 KT | 2019-May-28 | 0.8 LD | 11.6 | 17 |
2003 LH | 2019-May-28 | 15.6 LD | 7.4 | 32 |
2019 JH8 | 2019-May-28 | 9.1 LD | 6.9 | 18 |
2019 KV | 2019-May-29 | 7.1 LD | 5.6 | 21 |
2019 KH | 2019-May-29 | 15.4 LD | 9.8 | 51 |
2011 HP | 2019-May-30 | 12.3 LD | 8.4 | 135 |
2019 KG2 | 2019-May-30 | 2.7 LD | 12 | 24 |
2019 KJ2 | 2019-May-31 | 13.7 LD | 1.7 | 13 |
2019 KL2 | 2019-Jun-01 | 8.7 LD | 4.5 | 11 |
2019 KU | 2019-Jun-01 | 16.1 LD | 6.1 | 18 |
2019 KH1 | 2019-Jun-02 | 10.6 LD | 18.5 | 29 |
2012 KZ41 | 2019-Jun-03 | 3.8 LD | 12 | 34 |
2019 KE2 | 2019-Jun-04 | 19.9 LD | 9.3 | 46 |
2019 KY | 2019-Jun-04 | 5.5 LD | 6.2 | 19 |
2019 KS | 2019-Jun-04 | 12.3 LD | 17.6 | 36 |
2019 KA3 | 2019-Jun-06 | 4 LD | 3.9 | 9 |
2019 JX2 | 2019-Jun-06 | 13.8 LD | 7 | 42 |
2014 MF18 | 2019-Jun-06 | 8.8 LD | 3 | 22 |
2019 KG3 | 2019-Jun-11 | 16.4 LD | 6.8 | 27 |
2013 YA14 | 2019-Jun-14 | 14.7 LD | 11.1 | 65 |
2019 KJ | 2019-Jun-14 | 12.6 LD | 8.1 | 68 |
441987 | 2019-Jun-24 | 7.7 LD | 12.6 | 178 |
2008 KV2 | 2019-Jun-27 | 17.8 LD | 11.4 | 195 |
2016 NN15 | 2019-Jun-28 | 9.6 LD | 8.4 | 16 |
2015 XC352 | 2019-Jul-01 | 11.9 LD | 4.1 | 26 |
2016 OF | 2019-Jul-07 | 12.8 LD | 8.5 | 85 |
2016 NO56 | 2019-Jul-07 | 3.4 LD | 12.2 | 26 |
2019 KD3 | 2019-Jul-12 | 15.5 LD | 8 | 89 |
2016 NJ33 | 2019-Jul-12 | 15 LD | 4.5 | 32 |
2015 HM10 | 2019-Jul-24 | 12.2 LD | 9.5 | 68 |
2010 PK9 | 2019-Jul-26 | 8.2 LD | 16.5 | 155 |
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.
| The official U.S. government space weather bureau |
| The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. |
| 3D views of the sun from NASA's Solar and Terrestrial Relations Observatory |
| Realtime and archival images of the Sun from SOHO. |
| from the NOAA Space Environment Center |
| fun to read, but should be taken with a grain of salt! Forecasts looking ahead more than a few days are often wrong. |
| from the NOAA Space Environment Center |
| the underlying science of space weather |
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