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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RARE BLUE STARTER: We all know what comes out of the bottom of thunderstorms: lightning bolts. But on Oct. 20th, Thomas Ashcraft of New Mexico saw something coming out of the top. "I captured a form of a transient luminous event called a 'blue starter' shooting up from the top of a thunderstorm cloud," he says. "Blue starters are rarely captured from ground level and there are hardly any specimens on the internet."
Lightning scientist Oscar van der Velde explains this phenomenon: "A blue starter is an electric streamer discharge coming out of the top of a thundercloud, fanning out and reaching up to the stratosphere as high as 26 km altitude. First reported by UAF scientists Wescott and Sentman in 1995/1996, they were found to be different from blue jets, which reach 35-40 km height."
"Since then, there have been very few reports of blue starters," continues van der Velde. "It seems that unusual physical circumstances may be required to produce them. Also, geometry can prevent people from seeing blue starters when a cloud is nearby because the underbody of the cloud can block their view. At larger distances the blue/violet light does not make it to the observer due to scattering."
Blue starters and blue jets are cousins of sprites, another form of exotic lightning that shoots up instead of down. Sprites, however, are more frequently observed. Check them out in the realtime photo gallery:
Realtime Sprite Photo Gallery
CME IMPACT SPARKS NO STORMS: Arriving earlier than expected, a coronal mass ejection (CME) hit Earth's magnetic field on Oct. 24th at approximately 1900 UT. NASA's ACE spacecraft, located at the L1 point 1.5 million km upstream from Earth, detected the CME's leading edge about a half hour before it reached Earth:
Solar wind speeds abruptly jumped to more than 500 km/s as the CME passed by. The shockwave rattled Earth's magnetic field and caused electrical currents to flow through the ground of Norway's Lofoten islands: data. However, that's about all that happened. A full-fledged geomagnetic storm did not erupt, and few auroras have been reported. Why was the CME so ineffective? Its internal magnetic field did not connect to Earth's magnetic field; the mismatch mitigated the CME's impact. Aurora alerts: text or voice
Realtime Aurora Photo Gallery
MORNING PLANET SHOW: Set your alarm for dawn. Venus, Jupiter and Mars are gathering for a three-way close encounter in the early morning sky. Yesterday, Kouji Ohnishi woke up early and photographed the convergence from Iiyama, Nagano, Japan. He calls this composition Reverie in Autumn:
"I could see the planets even through deep fog," says Ohnishi. "It was a wonderful morning."
The next five mornings will be equally wonderful. From Oct. 25th to Oct. 29th Venus, Jupiter and Mars will fit together inside a circle only 5o wide (sky maps: #1, #2, #3, #4, #5). Super-bright Venus and Jupiter are visible even after the black pre-dawn sky turns cobalt blue. Once you find them, you will have little trouble locating the dimmer red planet Mars. Enjoy the show!
Realtime Space Weather 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. 25, 2015, the network reported 22 fireballs.
(15 sporadics, 6 Orionids, 1 epsilon Geminid)
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 25, 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. 20, 2015 ||Stratospheric Radiation (+37o N) |
|Cosmic ray levels are elevated (+5.8% 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) |
RADS ON A PLANE: Spaceweather.com and the students of Earth to Sky Calculus regularly fly balloons to the stratosphere to measure cosmic rays. For the past six months, May through Oct. 2015, they have been taking their radiation sensors onboard commercial airplanes, too. The chart below summarizes their measurements on 18 different airplanes flying back and forth across the continental United States.
The points on the graph indicate the dose rate of cosmic rays inside the airplanes compared to sea level. For instance, the dose rate for flights that cruised at 40,000+ feet was more than 50x the dose rate on the ground below. No wonder the International Commission on Radiological Protection (ICRP) classifies pilots as occupational radiation workers.
Cosmic rays come from deep space. They are high energy particles accelerated toward Earth by distant explosions such as supernovas and colliding neutron stars. Astronauts aren't the only ones who have to think about them; flyers do, too. Cosmic rays penetrate deep inside Earth's atmosphere where airplanes travel every day.
This type of radiation is modulated by solar activity. Solar storms and CMEs tend to sweep aside cosmic rays, making it more difficult for cosmic rays to reach Earth. Low solar activity, on the other hand, allows an extra dose of cosmic rays to reach our planet. This is important because forecasters expect solar activity to drop sharply in the years ahead as we approach a new Solar Minimum. Cosmic rays are poised to increase accordingly.
The plot, above, tells us what is "normal" in 2015. How will it change as the solar cycle wanes? Stay tuned for regular updates.
| ||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 |