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SUNSET PLANETS: When the sun goes down tonight, step outside and look west. Venus and Mercury are shining through the twilight side-by-side. At closest approach on Jan. 10th the two planets will be only 0.7o apart, so close you can hide them both behind the tip of your pinky finger held at arm's length. The photo gallery shows what to expect.
MAGNETIC STORM ON COMET LOVEJOY? Around the world, observers of bright Comet Lovejoy (C/2014 Q2) are reporting activity in the comet's sinuous blue ion tail. Last night, Italian photographer Rolando Ligustri used a remotely-controlled telecope in Spain to capture this 'plasma blob' billowing down the tail, away from the comet's core:
This could be a sign that a magnetic storm in underway. 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.
For readers who wish to monitor the effects of space weather on Lovejoy, the comet is easy to find. It is shining like a 4th magnitude star (barely visible to the unaided eye and an easy target for backyard telescopes) not far from the constellation Orion in the midnight sky. For accurate pointing of telescopes, please use this ephemeris from the Minor Planet Center.
Realtime Comet Photo Gallery
FLYING WITH COSMIC RAYS: In an ongoing experiment to measure space radiation inside commercial airplanes, Dr. Tony Phillips flew from Phoenix to Reno on Jan. 5th, then repeated the trip in reverse on Jan. 6th. Onboard both flights he carried a pair of ionizing radiation detectors sensitive to energies typical of medical X-rays. At cruising altitudes near 39,000 feet, he measured dose rates approximately 40 times higher than at ground level:
The radiation comes from space. Cosmic rays are subatomic particles accelerated to nearly light speed by supernovas, active galactic nuclei, and solar flares. Earth is peppered with this kind of radiation, every day, from all directions. Cosmic rays penetrate our planet's atmosphere, producing a spray of secondary particles that air travelers routinely (and mostly unknowingly) absorb as they fly. According to the rates Phillips measured, a passenger flying for 5 hours would be exposed to about as much radiation as a dental X-ray.
The data for Jan. 5th and Jan. 6th are in good agreement--as they should be. The two planes cruised at almost exactly the same altitude, took off at the same time of day, and traced the same path between Reno and Phoenix. Nevertheless, there is growing evidence of variability. Phillips took the same flight from Reno to Phoenix on Nov. 11, 2014. He measured 40% more radiation then vs. now. The difference is not fully understood.
Stay tuned as the investigation continues.....
Realtime Space Weather Photo Gallery
FLYING WITH AURORAS: Space weather can be very unpredictable. Jan. 7th was a case in point. A coronal mass ejection (CME) that no one knew was coming hit Earth's magnetic field, sparking a strong (Kp=7) geomagnetic storm. Spaceweather.com reader Jun Lao was flying on a plane when the storm erupted:
"I had the good fortune being on a Delta Airlines flight from Tokyo to Detroit on Wednesday, Jan. 7, and had an economy window seat on the left," reports Lao. "At around 8 a.m. EST, I looked out the window and noticed some diffuse light to the plane's north and east that were above the wing of the plane. I took out my Nikon D7000 and clicked away - they turned out green - aurora borealis! At that time, the plane was flying northwest of Anchorage, Alaska in what I believe was about 4 a.m. Alaskan Standard Time." Soon, the display intensified, and this is what appeared in the window:
"The display changed quite rapidly, probably due in part to the plane moving rapidly and changing my perspective," continues Lao "My fellow passengers were probably wondering why I was clicking away with a camera and the airplane blanket around it, to block the lights and video monitor reflections on the double pane airplane window. Alas, as the display started to fade and the sky was turning lighter, the plane lights went on for the crew to serve the 'midnight' snack." And so the show came to an end...
"When I got home in Mason, Ohio later in the evening, I checked Spaceweather.com and found that an unexpected geomagnetic storm had occured that day! What a nice blessing it was for me to be flying back to the US during the event." Aurora alerts: text, voice
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 Jan. 9, 2015, the network reported 15 fireballs.
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 January 9, 2015 there were 1532 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 || |
|2014 YE42 || |
|2014 YP34 || |
|2007 EJ || |
|1991 VE || |
|2004 BL86 || |
|2008 CQ || |
|2000 EE14 || |
| ||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 |