Marianne's Heaven On Earth Aurora Chaser Tours Chasethelighttours.co.uk invites you to join them in their quest to find and photograph the Aurora Borealis. Experience the winter wonderland in the Tromsø Area.
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GEMINID METEOR SHOWER--TONIGHT! The annual Geminid meteor shower peaks tonight, Dec. 13-14, as Earth passes through a stream of gravelly debris from "rock comet" 3200 Phaethon. Dark-sky observers in both hemispheres could see as many as 120 meteors per hour during the dark hours between midnight and sunrise on Dec. 14th. Last night, Dec. 12-13, NASA's all-sky meteor network detected 15 Geminid fireballs over the USA. That number will surely grow on peak night--tonight! Got clouds? Listen for Geminid echoes in the audio feed from our live meteor radar.
MAGNETIC STORM ON COMET CATALINA: Earth isn't the only place with geomagnetic storms. Comets can have them, too. Such a storm appears to be underway in the sinuous blue ion tail of Comet Catalina (C/2013 US10). Note the blobs of plasma circled in this Dec. 11th photo taken by Michael Jäger of Jauerling, Austria:
These blobs are a sign of stormy space weather. Observers of comets frequently witness plasma blobs and 'disconnection events' in response to CMEs and gusts of solar wind. In extreme cases, a comet's tail can be completely torn off.
The underlying physics is akin to terrestrial geomagnetic storms. When magnetic fields around a comet bump into oppositely-directed magnetic fields in a CME, those fields can link together or "reconnect." The resulting burst of magnetic energy can make waves, blobs, or even ruptures in the comet's tail. When CMEs hit Earth, a similar process takes place in the planet's magnetosphere powering, among other things, the aurora borealis.
Comet Catalina is brightening in the eastern pre-dawn sky, not yet visible to the naked eye, but an easy target for backyard telescopes. Detailed finder charts may be found in this article from Sky & Telescope. Monitoring is encouraged. Resources: 3D orbit, ephemerides. Aurora alerts: text or voice
Realtime Comet Photo Gallery
HILLSIDE GREEN FLASH: Green flashes are rare and lovely. They are most often seen by people on beaches at the end of the day. As the sun sinks into the waves, temperature gradients in the air above the sea surface magnify tiny differences in atmospheric refraction of red and green light. Voila!--an emerald-green mirage.
Not every green flash, however, requires an ocean. This one, photographed by Daisuke Tomiyasu of Higashinada-ku, Japan, appeared over a hill:
"I saw this green flash at sunrise on Dec. 8th," says Tomiyasu. "Once I knew this hill produced green flashes, I returned the next morning, Dec. 9th, and there it was again!"
Atmospheric optics expert Les Cowley explains what happened: "Green flashes come in several varieties. These could be hillside flashes. When wind blows over a hilly ridge the air streamlines are pushed closer together and any small vertical temperature gradients are strengthened. The bending of sunrays across the gradients gets stronger too and maybe enough to create the mirage conditions that all green flashes need."
Realtime Space Weather Photo Gallery
Realtime Aurora Photo Gallery
Realtime Meteor 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 Dec. 13, 2015, the network reported 29 fireballs.
(15 Geminids, 10 sporadics, 2 December Monocerotids, 1 Quadrantid, 1 alpha Canis Majorid)
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 December 13, 2015 there were potentially hazardous asteroids. 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 |
These measurements are based on regular space weather balloon flights: learn more.
|Situation Report -- Oct. 30, 2015 ||Stratospheric Radiation (+37o N) |
|Cosmic ray levels are elevated (+6.1% above the Space Age median). The trend is flat. Cosmic ray levels have increased +0% in the past month. |
|Sept. 06: 4.14 uSv/hr (414 uRad/hr) |
|Sept. 12: 4.09 uSv/hr (409 uRad/hr) |
|Sept. 23: 4.12 uSv/hr (412 uRad/hr) |
|Sept. 25: 4.16 uSv/hr (416 uRad/hr) |
|Sept. 27: 4.13 uSv/hr (413 uRad/hr) |
|Oct. 11: 4.02 uSv/hr (402 uRad/hr) |
|Oct. 22: 4.11 uSv/hr (411 uRad/hr) |
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. Our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing radiation as 2 to 5 dental X-rays. Here is the data from our latest flight, Oct. 22nd:
Radiation levels peak at the entrance to the stratosphere in a broad region called the "Pfotzer Maximum." This peak is named after physicist George Pfotzer who discovered it using balloons and Geiger tubes in the 1930s. Radiation levels there are more than 80x sea level.
Note that the bottom of the Pfotzer Maximim is near 55,000 ft. This means that some high-flying aircraft are not far from the zone of maximum radiation. Indeed, according to the Oct 22th measurements, a plane flying at 45,000 feet is exposed to 2.79 uSv/hr. At that rate, a passenger would absorb about one dental X-ray's worth of radiation in about 5 hours.
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.
| ||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 |
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