Lights Over Lapland has a brand-new website full of exciting adventures in Abisko National Park, Sweden! Take a look at our aurora activities and book your once-in-a-lifetime trip with us today! | | |
ATMOSPHERIC COSMIC RAYS ARE INCREASING: So you thought Solar Minimum was boring? Think again. High-altitude balloon flights show that atmospheric radiation is intensifying from coast to coast over the USA--a direct result of low solar activity. Get the full story.
A NEW SPACE WEATHER METRIC: The Thermosphere Climate Index (TCI) is now on Spaceweather.com. TCI is a relatively new space weather metric that tells us how the top of Earth's atmosphere (or "thermosphere") is responding to solar activity. During Solar Max the top of our atmosphere heats up and expands. Right now the opposite is happening. Solar minimum is here and the thermosphere is cooling off:
TCI was invented by Martin Mlynczak of the Langley Research Center along with other NASA and university colleagues. For the past 17 years they have been using the SABER instrument onboard NASA's TIMED satellite to monitor the wattage of infrared emissions from the top of the atmosphere. Recently, they realized that these measurements could be used to summarize the state of the thermosphere in a single daily number–the TCI. Moreover, they learned to calculate TCI going back in time all the way to the 1940s, thus placing current conditions in a historical context.
So where do we stand? Right now TCI=4.6x1010 W. That means the top of Earth's atmosphere is approximately 10 times cooler than it was during the record-setting Solar Max of 1957-58 (TCI=49.4x1010 W). The current record low, TCI=2.1x1010 W, was set in 2009 less than ten years ago during the previous Solar Minimum. We're not quite there yet, but were getting close.
You can monitor daily values of TCI right here on SpaceWeather.com. TCI not only tracks the slow progression of the 11-year solar cycle, but also it can change suddenly in response to solar flares and geomagnetic storms. As these events occur, we'll be writing about them to raise awareness of the many ways the sun can dump energy into Earth's atmosphere. Stay tuned!
Realtime Space Weather Photo Gallery
A MOONSTONE IN THE STRATOSPHERE: Are you looking for a far-out gift? Nothing says "I love you" like a moonstone from the edge of space. On June 12th, the students of Earth to Sky Calculus flew this moonstone wrapped in a sterling silver Celtic love knot 34.1 km (111,877 feet) above Earth's surface:
You can have it for $149.95. The students are selling these pendants to support their cosmic ray ballooning program. Each one comes with a greeting card showing the item in flight and telling the story of its journey to the edge of space. 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
AFRICAN ICE HALO: You never know what you might see when you go on safari. "Earlier this week I was riding through Choose National Park in Botswana," says George Kourounis. "While the rest of the people in the vehicle were scanning the bushes, looking for lions and leopards, I was looking up in the sky at this complex solar halo."
"It was almost like a giant eye in the sky looking down at us," says Kourounis. "I've never seen anything like it."
Halos like this are caused ice crystals in high cirrus clouds. Shaped like pencils, long and thin with 6 sides, the crystals bend and refract sunlight into a variety of shapes. Shown above is a 22-degree circular halo, a circumscribed halo, and a fraction of a full parhelic circle.
Some people think ice halos are rare in Africa--but they are not. The air 10 km high is freezing over Africa just like everywhere else. Safari-goers should definitely look up, from time to time.
INFERIOR CONJUNCTION OF VENUS: Today, Oct. 26th, Venus is at inferior solar conjunction. In other words, Venus is passing almost directly between Earth and the sun. Shahrin Ahmad photographed Venus in broad daylight from Kuala Lumpur, Malaysia:
"Venus was a mere 6 deg 24 min from the sun!" says Ahmad. "The sky around it was super blue and clear."
During inferior conjunction, Venus turns its night side toward Earth, showing itself only by dint of sunlight scattered in a thin crescent around the edge of its atmosphere. When Venus is very close to the sun, that crescent can close upon itself, making a complete circle. "The horns or cusps of Venus have already gone beyond 180º, but they have not completely closed," notes Ahmad.
This is arguably the most beautiful time to observe Venus, but also the most perilous. The glare of the nearby sun magnified by a telescope can damage the eyes of anyone looking through the eyepiece.
Anthony J. Cook of the Griffith Observatory has some advice for observers: "I have observed Venus at conjunction, but only from within the shadow of a building, or by adding a mask to the front end of the telescope to fully shadow the optics from direct sunlight. This is tricky with a refractor or a catadioptric, because the optics start at the front end of the tube. Here at Griffith Observatory, I rotate the telescope dome to make sure the lens of the telescope is shaded from direct sunlight, even through it means that the lens will be partially blocked when aimed at Venus. With our Newtonian telescope, I add a curved cardboard mask at the front end of the tube to shadow the primary mirror."
Realtime Venus Photo Gallery
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 Oct. 26, 2018, the network reported 30 fireballs.
(21 sporadics, 7 Orionids, 1 epsilon Geminid, 1 Leonis Minorid)
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 26, 2018 there were 1936 potentially hazardous asteroids.
|
Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
2018 US1 | 2018-Oct-21 | 2.3 LD | 7.1 | 14 |
2018 UC2 | 2018-Oct-23 | 9.4 LD | 19.4 | 152 |
2018 UH1 | 2018-Oct-24 | 5.3 LD | 13 | 35 |
2018 TT5 | 2018-Oct-24 | 15.9 LD | 10.2 | 29 |
2018 UE | 2018-Oct-25 | 17.3 LD | 16.1 | 44 |
475534 | 2018-Oct-29 | 7.5 LD | 18.1 | 204 |
2018 UC | 2018-Oct-30 | 5.4 LD | 9.3 | 22 |
2018 UY1 | 2018-Nov-04 | 7.4 LD | 8.3 | 56 |
2002 VE68 | 2018-Nov-04 | 14.7 LD | 8.6 | 282 |
2018 TF3 | 2018-Nov-05 | 7.8 LD | 20.6 | 302 |
2010 VQ | 2018-Nov-07 | 15.6 LD | 3.8 | 10 |
2018 UQ1 | 2018-Nov-13 | 9.4 LD | 12.3 | 151 |
2009 WB105 | 2018-Nov-25 | 15.2 LD | 18.9 | 71 |
2008 WD14 | 2018-Nov-27 | 7.4 LD | 9.3 | 93 |
2001 WO15 | 2018-Nov-28 | 13.6 LD | 11.7 | 107 |
2018 TG6 | 2018-Dec-02 | 3.9 LD | 1.4 | 12 |
2013 VX4 | 2018-Dec-09 | 4.1 LD | 6.6 | 65 |
2015 XX169 | 2018-Dec-13 | 17 LD | 5.8 | 12 |
2017 XQ60 | 2018-Dec-21 | 11.3 LD | 15.6 | 47 |
163899 | 2018-Dec-22 | 7.4 LD | 6.2 | 1232 |
418849 | 2018-Dec-23 | 16.6 LD | 17.6 | 269 |
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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