Come to Tromsø and share Marianne's passion for rural photography: Chasethelighttours.co.uk invites you to experience "Heaven on Earth" with an aurora, fjord, fishing, whale watching, photography or sightseeing tour.
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CHANCE OF STORMS: A stream of solar wind has been blowing around our planet all weekend. So far, however, the action of the stream has not sparked a geomagnetic storm. NOAA forecasters estimate a 30% chance that a storm will finally break out before the weekend is over. Aurora alerts: text or voice.
NEUTRONS ON A PLANE: Want to experience space weather? It's easy. Just step onboard an airplane. Recently, Spaceweather.com and the students of Earth to Sky Calculus have been monitoring cosmic radiation levels in the cabins of commercial jets. Measurements of X-rays and gamma-rays show that travelers absorb the equivalent of one or more dental X-rays on a typical flight across the USA. But X-rays and gamma-rays represent only a fraction of the total radiation evnvironment. On July 23, 2015, for the first time, they carried a neutron bubble chamber onboard. Here is what the chamber looked like at the end of a 5 hour flight from Boston to Las Vegas:
Each of the bubbles is formed by an energetic neutron passing through the chamber. By counting the bubbles, it is possible to estimate the total dose of neutron radiation. The answer, for this particular flight, was 1240 microRads (energy range 200 keV - 15 MeV). How does this compare to ionizing radiation? X-ray and gamma-ray sensors carried onboard the same plane accumulated a lesser dose of 860 microRads (energy range 10 keV to 20 MeV).
Lesson: When characterizing the radiation environment inside an airplane, neutrons are at least as important as X-rays and gamma-rays.
Among researchers it is well known that neutrons are an important form of cosmic rays, providing much of the biologically effective radiation dose at altitudes of interest to aviation and space tourism. Low-energy neutrons also cause single-event upsets in aircraft avionics, especially devices that contain Boron 10.
During the five hours of the July 23rd flight, the radiation sensors accumulated a total dose of 2100 microRads (neutrons + X-rays + gamma-rays). This is ~140 times the dose of cosmic rays at sea level during the same 5 hours.
Stay tuned for updates as we continue our measurements of atmospheric radiation.
WHAT COLOR WAS THE BLUE MOON? On Friday night, sky watchers around the world witnessed the second full Moon of July. According to modern folklore, it was a "Blue Moon." So much for folklore. In most places, the rising Moon turned red:
Bill Metallinos sends this picture from Corfu, Greece. "The amber-colored Blue Moon rose behind the the Fortress of San Marco while little Constantina, my niece, waved hello to us with her mother and father," he says.
Many people think Moons cannot turn blue. In fact, ash from volcanoes can do the trick. Volcanic aerosols of just the right size, about 1 micron in diameter, scatter all the red out of moonlight and turn the lunar disk blue.
More often, however, the Moon turns red. It happens for the same reason that sunsets are red. The everyday atmosphere is full of aerosols much smaller than the ones injected by volcanoes. These aerosols scatter blue light, while leaving the red behind.
A red Blue Moon? It may sound absurd, but that's what Blue Moons are all about. Browse the realtime photo gallery for more examples:
Realtime Space Weather Photo Gallery
Realtime Aurora Photo Gallery
Realtime Sprite Photo Gallery
Realtime NLC 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 Aug. 2, 2015, the network reported 27 fireballs.
(15 sporadics, 7 Perseids, 5 alpha Capricornids)
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 August 2, 2015 there were potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters: 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.
|Asteroid || |
|2005 NZ6 || |
|2005 JF21 || |
|2004 BO41 || |
|1991 CS || |
|2014 KS76 || |
|2004 TR12 || |
| ||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 |
| ||the underlying science of space weather |
| ||Web-based high school science course with free enrollment |