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! | | |
COSMIC RAY UPDATE: Note to astronauts: 2019 is not a good year to fly into deep space. In fact, it's shaping up to be one of the worst of the Space Age. According to a new paper just published in the journal Space Weather, cosmic rays are flooding into the solar system as the sun's magnetic field weakens, posing a health risk to space travelers. Full story.
THE CRATERS OF APOLLO 11: 50 years ago, astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins were hurtling toward the Sea of Tranquility, preparing themselves for the first Moon landing. With memories of Apollo 11 on his mind, Australian amateur astronomer Dennis Simmons turned his telescope toward their landing site last night, and this is what he saw:
"I managed to pinpoint and image the craterlets Armstrong, Aldrin and Collins located in Mare Tranquillitatis, using my 201mm diameter telescope from my back yard in Brisbane," says Simmons.
These three craters were named after the astronauts following the successful Apollo 11 mission. They're all small, with diameters of 4.6 kilometers (Armstrong), 3.4 km (Aldrin) and 2.4 km (Collins). Amateur astronomers often use the craters as guides to find the landing site itself by "triangulating" it with, say, Armstrong and Aldrin.
"Was it really 50 years ago when I watched this stupendous achievement of my neighbor's B&W TV in the early hours of the morning…?" marvels Simmons. "What a moment in history."
NOCTILUCENT CLOUD SIGHTINGS: As the summer solstice recedes, darkness is slowly returning to far-northern skies--just enough to see noctilucent clouds (NLCs). P-M Hedén photographed this display over Vallentuna, Sweden, on July 18th:
"The NLCs were really strong ," says Hedén. "I went to a local lake with totally calm water and could capture the strings of NLC as reflections in the water. NLCs are peaking here in the middle of Sweden!"
NLCs are Earth's highest clouds. They form every year in June and July when 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 ~83 km high. When sunbeams hit those crystals, they glow electric-blue.
2019 has been a remarkable year for NLCs, with sightings as far south as New Mexico and southern California. The retreat of Arctic twilight is now allowing Scandinavian observers a good view as well.
News! NASA's AIM spacecraft, launched in 2007 to study noctilucent clouds (NLCs), suffered a minor anomaly this week. Members of the science team are optimistic that normal operations will be restored soon. Meanwhile, there may be a gap in Spaceweather.com's "Daily Daisy" coverage of NLCs around the north pole. Aurora alerts: SMS Text
Realtime Noctilucent Cloud Photo Gallery
Note: Spaceweather.com Newsletter
APOLLO 11 ANNIVERSARY SILVER DOLLAR: The 50th anniversary of the Apollo 11 Moon landing is only one day away. To mark the occasion, the students of Earth to Sky Calculus have been flying commemorative Apollo 11 silver dollars to the stratosphere and selling them to support their cosmic ray balloon program. Buy one this week and we will fly it to the stratosphere on July 20, 2019, exactly 50 years after Neil Armstrong set foot on the Moon.
We plan to fly only a small number of these coins to the edge of space on July 20, 2019. Reserve yours for $197.95.
Created by the US Mint, the proof-quality 99% 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 coin comes with a greeting card showing the item in flight on the 50th anniversary of the Moon landing and a certificate of authenticity.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter
Realtime Aurora Photo Gallery
Free: Spaceweather.com Newsletter
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 Jul. 19, 2019, the network reported 14 fireballs.
(13 sporadics, 1 alpha Capricornid)
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 July 19, 2019 there were 1983 potentially hazardous asteroids.
|
Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
2019 NQ5 | 2019-Jul-14 | 11.5 LD | 9.9 | 34 |
2019 NR3 | 2019-Jul-14 | 16.8 LD | 4.8 | 20 |
2019 NB7 | 2019-Jul-15 | 2.3 LD | 12.8 | 12 |
2019 OB | 2019-Jul-16 | 2.7 LD | 14.9 | 23 |
2019 NF1 | 2019-Jul-17 | 19.3 LD | 10 | 56 |
2019 NJ2 | 2019-Jul-19 | 13.4 LD | 13.5 | 38 |
2015 HM10 | 2019-Jul-24 | 12.2 LD | 9.5 | 68 |
2010 PK9 | 2019-Jul-26 | 8.2 LD | 16.5 | 155 |
2019 NT1 | 2019-Jul-27 | 19 LD | 3.7 | 14 |
2019 NN4 | 2019-Jul-29 | 6.6 LD | 3.8 | 25 |
2006 QQ23 | 2019-Aug-10 | 19.4 LD | 4.7 | 339 |
454094 | 2019-Aug-12 | 17 LD | 8.2 | 148 |
2018 PN22 | 2019-Aug-17 | 17.1 LD | 2.3 | 11 |
2016 PD1 | 2019-Aug-26 | 11.4 LD | 5.9 | 65 |
2002 JR100 | 2019-Aug-27 | 19.4 LD | 8.4 | 49 |
2018 DE1 | 2019-Sep-03 | 12.7 LD | 6.6 | 28 |
2019 GT3 | 2019-Sep-06 | 19.5 LD | 13.6 | 227 |
2010 RM82 | 2019-Sep-13 | 18.2 LD | 14.6 | 23 |
2013 CV83 | 2019-Sep-13 | 15.7 LD | 13.1 | 62 |
504800 | 2019-Sep-14 | 13.9 LD | 14.4 | 155 |
467317 | 2019-Sep-14 | 13.9 LD | 6.4 | 389 |
2019 JF1 | 2019-Sep-16 | 11.2 LD | 4.3 | 61 |
2018 FU1 | 2019-Sep-16 | 18.4 LD | 4.7 | 16 |
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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