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! | | |
THE NEXT STREAM OF SOLAR WIND: A minor stream of solar wind flowing from a southern hole in the sun's atmosphere is expected to reach Earth on Oct. 3rd or 4th. Its impact probably won't spark a full-fledged geomagnetic storm. Lesser geomagnetic unrest and auroras are possible, however, especially around the Arctic Circle. Aurora alerts: SMS Text.
A "STEVE STORM" HITS SCANDINAVIA: When a stream of solar wind hit Earth's magnetic field last Friday, Sept. 27th, forecasters expected an aurora storm around the Arctic Circle. Turns out, it was more of a "STEVE storm." Many sky watchers in Scandinavia saw the mauve ribbon of light for the very first time. Göran Strand photographed the event from Handöl, Sweden:
"I finally got to see STEVE," says Strand, who is a veteran observer of auroras, but had never seen STEVE before. "It all started when I noticed a faint green corona outside our mountain cabin. I grabbed my camera gear and headed out into the night. At my first stop along this road I encountered STEVE."
STEVE (Strong Thermal Emission Velocity Enhancement) looks like an aurora, but it is not. The phenomenon is caused by hot (3000°C) ribbons of gas flowing through Earth’s magnetosphere at speeds exceeding 6 km/s (13,000 mph). These ribbons appear during some geomagnetic storms, revealing themselves by their soft purple/mauve glow.
STEVE normally appears at latitudes around +50N to +55N, on rare occasions dipping down into the +40s. In this case, however, the sightings were at unusually high latitudes, topping +60N in Handöl, Sweden (+63.3N); Ruovesi, Finland (+62.0N); Turku, Finland (+60.5N) and, if we round up a little, Laguja, Estonia (+58.2N). This event shows that the habitat of STEVE may reach farther north than previously thought.
Realtime STEVE Photo Gallery
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A GREEN FLASH ON VENUS: You've heard of green flashes on the sun. But what about green flashes on Venus? They're real, and now is a good time to observe them. All you need is a body of water, a sunset, and a telescope.
"I saw one last week," reports eye-witness Paolo Palma of Rome, Italy. "At the end of the day on Sept. 26th I was watching the sunset from my deck overlooking the Tyrrhenian Sea. A fragment of the setting sun seemed to break away and turn a strong shade of green, like a leaf falling on the nearby sea."
It was a green flash--something that happens fairly often to the setting sun when temperature inversions and strong thermal gradients develop above the sea surface.
"The sky was clear," continues Palma, "and I had my Dobsonian telescope with me. I decided to swing my telescope up to Venus, which itself was only a few degrees above the horizon. As it sank toward the sea, it had a green flash, too!"
Green flashes on the sun happen because the low atmosphere acts like a prism, splitting the solar disk into primary R-G-B colors. Temperature gradients above the sea surface can magnify the green into an eye-catching flash. It's a type of mirage.
The same physics that makes green flashes on the sun can make green flashes on Venus. In fact, green flashes on Venus may be even easier to create.
Atmospheric optics expert Les Cowley explains: "Planets and especially point-source stars need less stringent conditions as evidenced by Paolo's observation of Venus spreading into a color strip while it was still well above the horizon. Mirages just do not get that high. Normal atmospheric refraction is sufficient to do this." When Venus approaches the horizon, mirage conditions kick in, magnifying the green for a truly verdant flash.
Now is a good time to observe Venusian green flashes. The second planet is just emerging from solar conjunction. So, when the sun sets into the waves, Venus is not far behind, sampling the same thermal conditions as the green-flashing sun. Seaside sky watchers should be alert for the phenomenon in the evenings ahead.
Observing tips: Venus may not be easy to find in the bright twilight of sunset. Having trouble? Try using binoculars when the sun is safely below the horizon. Please be very careful not to accidentally look at the sun through unfiltered optics of any kind. Even when the sun is hanging low, magnified sunlight can cause serious eye damage.
Realtime Green Flash Photo Gallery
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CROWD-FUNDING SPACE WEATHER RESEARCH: Did you know that cosmic rays in Earth's atmosphere are intensifying? It's true. We're monitoring the phenomenon with regular space weather balloon flights to the stratosphere. This student science program is not supported by any government grant or corporate sponsorship. Instead, we raise our research funds by selling these:
This pendant, and others like it, have touched the edge of space. We fly them to the stratosphere alongside our cosmic ray sensors for fundraising.
You can have one for $199.95. With a sterling silver backface that says "I Love You to the Moon and Back," these blue jewels make great anniversary, Christmas and birthday gifts. All sales support the Earth to Sky Calculus cosmic ray ballooning program and hands-on STEM research.
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
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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 Oct. 2, 2019, the network reported 24 fireballs.
(23 sporadics, 1 southern Taurid)
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 October 2, 2019 there were 2018 potentially hazardous asteroids.
|
Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
2019 SO8 | 2019-Sep-27 | 7.7 LD | 9.5 | 16 |
2019 SC6 | 2019-Sep-27 | 1.4 LD | 16.5 | 10 |
2019 TB | 2019-Sep-27 | 6.1 LD | 5.9 | 14 |
2006 QV89 | 2019-Sep-27 | 18.1 LD | 4.1 | 31 |
2019 ST8 | 2019-Sep-27 | 7.3 LD | 17 | 32 |
2019 SB9 | 2019-Sep-27 | 2.6 LD | 10.3 | 9 |
2019 SX8 | 2019-Sep-28 | 1 LD | 8.4 | 6 |
2019 SF9 | 2019-Sep-28 | 2 LD | 14.3 | 47 |
2019 TE | 2019-Sep-28 | 0.9 LD | 19.6 | 9 |
2019 TA | 2019-Sep-29 | 1.2 LD | 6.2 | 5 |
2019 SE5 | 2019-Sep-29 | 5.7 LD | 6.6 | 15 |
2019 SO1 | 2019-Sep-29 | 11.3 LD | 7.5 | 16 |
2019 SA5 | 2019-Sep-29 | 19.2 LD | 7.8 | 25 |
2019 TD | 2019-Sep-29 | 0.3 LD | 10.1 | 5 |
2019 TF | 2019-Sep-29 | 18 LD | 10 | 11 |
2019 SN4 | 2019-Sep-29 | 6.5 LD | 19.6 | 48 |
2019 TC | 2019-Sep-29 | 14.5 LD | 12.3 | 17 |
2019 SH3 | 2019-Sep-30 | 3.1 LD | 14.2 | 27 |
2019 SN3 | 2019-Sep-30 | 2.2 LD | 7.7 | 16 |
2019 SP | 2019-Sep-30 | 6.6 LD | 15.1 | 46 |
2019 SJ9 | 2019-Oct-01 | 7.8 LD | 8.4 | 13 |
2019 SM8 | 2019-Oct-01 | 0.4 LD | 14.2 | 5 |
2019 SE8 | 2019-Oct-01 | 2.8 LD | 22.8 | 15 |
2019 SE9 | 2019-Oct-01 | 14.1 LD | 4.1 | 37 |
2018 FK5 | 2019-Oct-01 | 13.3 LD | 10.5 | 8 |
2019 SD8 | 2019-Oct-02 | 1.4 LD | 10.9 | 12 |
2019 SX3 | 2019-Oct-02 | 8.7 LD | 8.7 | 30 |
2019 SA6 | 2019-Oct-02 | 11.8 LD | 16.6 | 30 |
2018 LG4 | 2019-Oct-02 | 13.8 LD | 8.1 | 12 |
2019 SL8 | 2019-Oct-03 | 7.9 LD | 13.3 | 24 |
2019 SP3 | 2019-Oct-03 | 1 LD | 8.7 | 20 |
2019 SH9 | 2019-Oct-03 | 4.6 LD | 14.9 | 10 |
2017 TJ4 | 2019-Oct-05 | 13.5 LD | 8.9 | 32 |
2019 SZ4 | 2019-Oct-06 | 18.7 LD | 6.5 | 25 |
2019 SB6 | 2019-Oct-08 | 7.7 LD | 7.9 | 16 |
2019 RK | 2019-Oct-08 | 16.7 LD | 3 | 30 |
2019 SL7 | 2019-Oct-09 | 1.4 LD | 17.1 | 21 |
2019 SX5 | 2019-Oct-10 | 17.7 LD | 21.8 | 84 |
2019 SK8 | 2019-Oct-12 | 10.5 LD | 8.5 | 21 |
2019 SV9 | 2019-Oct-12 | 8.6 LD | 13.6 | 30 |
2019 SE2 | 2019-Oct-12 | 19.2 LD | 10.2 | 54 |
2019 SR8 | 2019-Oct-16 | 13.5 LD | 9.8 | 26 |
2019 SJ8 | 2019-Oct-20 | 11.6 LD | 7.4 | 47 |
162082 | 2019-Oct-25 | 16.2 LD | 11.2 | 589 |
2017 TG5 | 2019-Oct-25 | 14.4 LD | 11.9 | 34 |
2015 JD1 | 2019-Nov-03 | 12.9 LD | 11.9 | 269 |
2010 JG | 2019-Nov-12 | 19.6 LD | 14.9 | 235 |
481394 | 2019-Nov-21 | 11.3 LD | 7.9 | 372 |
2008 EA9 | 2019-Nov-23 | 10.5 LD | 2.2 | 10 |
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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