Space Weather Update: 11/25/2015
By Spaceweather.com, 11/25/2015
FULL FROSTY MOON: There is a full Moon tonight, and it has a special name–the “Frosty Moon.” It gets its name from northern autumnal ground frost, which glistens beautifully in pale moonlight. Go outside tonight, look up and down, and enjoy the show. [photo gallery]
THANKSGIVING SKIES: Thanksgiving is the biggest travel holiday of the year in the United States. Millions of people board airplanes and fly long hours to visit friends and family. Dreading the trip? Think of it as a sky watching opportunity. There are some things you can see only through the window of an airplane, like this:
This is called “the glory“–a bulls-eye of softly colored rings surrounding the shadow of the airplane cast on cloudtops.
Atmospheric optics expert Les Cowley explains what causes it: “These rings are formed when light is scattered backwards by individual water droplets in the clouds. The more uniform the size of the droplets, the more rings you will see. They swell and contract as you travel over clouds with smaller or larger droplets.”
In this article, Cowley describes even more things you can see through the airplane window. Happy Thanksgiving!
JAPANESE ROCKET SURPRISES SKY WATCHERS: Unbeknownst to most people in North America, on Nov. 24th Japan launched an H-2A rocket carrying the Telstar 12 Vantage communications satellite. The resulting display surprised sky watchers in at least half a dozen states. “I was observing Comet Catalina before sunrise, when I noticed this thing halfway up towards Venus,” reports Glen Wurden of Los Alamos, New Mexico:
“It lasted for at least a half an hour after 5:40 AM,” he adds. “It was huge, easily naked eye, and kind of scary!”
SUNRISE COMET CATALINA: Discovered in 2013 by the Catalina Sky Survey, Comet Catalina (C/2013 US10) is making a one-time trip through the inner solar system. It swung around the sun on Nov. 15th and is now emerging in the dawn skies of the northern hemisphere. Peter Rosén photographed the comet over Stockholm, Sweden, on Nov. 23rd:
“I woke up very early this morning to catch a first glimpse of comet Catalina,” says Rosén. “While I waited for the comet to appear in the sunrise twilight, I spent my time observing Venus and Jupiter. As so often happens in Stockholm, the clouds rolled in and started covering the sky. I thought about giving up, but I noticed that there was still a strip of clear sky at the eastern horizon. Patience payed off and Comet Catalina even showed a thin tail at less than 3° above the horizon.”
Technically, Comet Catalina is a 6th magnitude object visible to the unaided eye. In practice, morning twilight overwhelms the comet’s faint glow. You need a telescope to see it. “The inset is shot with a Canon Eos5D through my WilliamOptics FLT-110 at prime focus,” says Rosén. Sky maps and observing tips are available from Sky & Telescope.
This is Comet Catalina’s first visit to the inner solar system–and its last. The comet’s close encounter with the sun in mid-November has placed it on a slingshot trajectory toward interstellar space. It will become easier to see in the weeks ahead as it recedes from the sun, possibly brightening to 5th magnitude in December. A date of special interest is Dec. 7th when the comet pairs up with the planet Venus and the waning crescent Moon in the early morning sky. Catalina will be about 4odegrees away from the Venus-Moon combo. Stay tuned for more information about that, and meanwhile browse the realtime comet gallery for more sightings.
AURORAS, FOR NO PARTICULAR REASON: Nov. 21st was a day of quiet space weather. There were no intense solar flares, no CMEs, and no geomagnetic storms. The auroras appeared anyway. Liselotte Kahns saw them over Sweden’s Abisko National Park:
“Despite the extremely low level of solar activity, Abisko’s clear sky demonstrated a nice aurora display tonight,” says Kahns. “[It’s] a good illustration of why this place is rated as one of the best places on Earth to see auroras.”
Indeed, it is not unusual for auroras to appear over Abisko even when the forecast calls for no magnetic activity. Aurora tour guides and photographers naturally gravitate toward the Park because of its frequently-green skies. The reason is Abisko’s location beneath Earth’s persistent auroral oval. A gentle rain of solar wind electrons, guided to Earth by our planet’s curved magnetic field, creates a polar ringof Northern Lights that intersects the latitude of Abisko, more often than not. Browse the realtime gallery for more sightings:
All Sky Fireball Network
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 Nov. 25, 2015, the network reported 15 fireballs.
(14 sporadics, 1 omicron Eridanid)
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]
Near Earth Asteroids
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 November 25, 2015 there were 1637 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:Asteroid
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
Situation Report — Oct. 30, 2015Stratospheric 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)
These measurements are based on regular space weather balloon flights: learn more.
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.
speed: 264.5 km/sec
density: 3.2 protons/cm3
explanation | more data
Updated: Today at 1637 UTX-ray Solar Flares
6-hr max: B7 1044 UT Nov25
24-hr: C1 0827 UT Nov25
explanation | more data
Updated: Today at: 1600 UTDaily Sun: 25 Nov 15Sunspot AR2457 has a ‘beta-gamma’ magnetic field that harbors energy forM-class solar flares. Credit: SDO/HMI
Sunspot number: 66
What is the sunspot number?
Updated 25 Nov 2015
Current Stretch: 0 days
2015 total: 0 days (0%)
2014 total: 1 day (<1%)
2013 total: 0 days (0%)
2012 total: 0 days (0%)
2011 total: 2 days (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
Updated 25 Nov 2015
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 0 quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 4.4 nT
Bz: 2.9 nT north
explanation | more data
Updated: Today at 1637 UTCoronal Holes: 25 Nov 15
There are no large coronal holes on the Earthside of the sun. Credit: SDO/AIA.Noctilucent Clouds The northern season for NLCs is finished. According to NASA’s AIM spacecraft, the last clouds were observed over Greenland on Aug. 27th. Now the waiting begins for the southern season expected to begin in November.
Switch view: Ross Ice Shelf, Antarctic Peninsula, East Antarctica, PolarUpdated at: 11-24-2015 22:55:03
Updated at: 2015 Nov 24 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2015 Nov 24 2200 UTCMid-latitudes