Space Weather Update: 10/11/2016
By Spaceweather.com, 10/11/2016
EARTH-DIRECTED CME: A magnetic filament in the sun’s northern hemisphere erupted on Oct. 8th, hurling a faint CME (movie) into space. NOAA analysts say the storm cloud could deliver a glancing blow to Earth’s magnetic field on Oct. 13th. Atthis time of year, even a minor CME impact can spark bright polar auroras, so stay tuned. Free: Aurora Alerts.
SURFING THE HELIOSPHERIC CURRENT SHEET: Yesterday, Oct. 10th, Earth passed through a fold in the heliospheric current sheet. The crossing sparked bright auroras around the Arctic Circle. “The lights were fantastic,” reports Helge Mortensen, who photographed the display over Kattfjordvannet, Norway:
“This little pond had a thin layer of ice,” he points out. “I guess winter is getting closer.”
Many people have never heard of the heliospheric current sheet. It is one of the biggest things in the solar system–a vast undulating system of electrical currents shaped like the skirt of a ballerina: picture. Earth dips in and out of it all the time.
URSUS STRATOSPHERUS: To fund their cosmic ray research, the students of Earth to Sky Calculus have flown 20 pairs of brown bears to the edge of space. Get your own pair for only $39.95–space helmets included. They make great gifts and Christmas stocking stuffers. Each adorable duo comes with a greeting card showing the bears in flight and certifying their trip to the stratosphere.
More funky edge-of-space gifts may be found in the Earth to Sky store. All proceeds support cosmic ray balloon launches and STEM education.
THE INTERCONTINENTAL SWx BALLOON NETWORK: For the past 2 years, Spaceweather.com and the students of Earth to Sky Calculus have been launching “space weather balloons” to measure cosmic rays in the atmosphere. Regular flights over California show that atmospheric radiation is intensifying in response to changes in the solar cycle. Now, our monitoring program is going global. In recent months we have been developing launch sites in multiple US states as well as South America and Europe. This is what the Intercontinental Space Weather Balloon Network looks like in October 2016:
Recent additions expand our coverage north of the Arctic Circle (Sweden) and closer to the core of the South Atlantic Anomaly (Argentina). We also hope to add a site in Antarctica in early 2018.
Why launch balloons from so many places? Deep-space cosmic rays bombard Earth from all directions, day and night. A single launch site is not enough to reveal the uneven shielding of our planet’s magnetic field and the complicated response of our atmosphere to changes in solar activity.
Our first test of the network validated these ideas. During a 48 hour period from August 20th-22nd we launched 4 balloons in quick succession from southern Chile, California, Oregon, and Washington. The ascending payloads sampled atmospheric radiation (X-rays and gamma-rays, 10 keV – 20 MeV) from ground level to the stratosphere over a geographical range of more than 10,000 km. Here are the results:
The curves show radiation levels vs. altitude for each of the four sites. Numbers in parentheses are magnetic latitude–a measure of distance from Earth’s magnetic equator.
At a glance, we can see that atmospheric radiation is a strong function of magnetic latitude. Washington State at +53o registered more than twice the dose rate of southern Chile at -29o. Why is Washington so high? Of all the sites, it is closest to Earth’s magnetic north pole, which provides less shielding against incoming cosmic rays. The more interesting question may be, Why is Chile so low? The Chilean balloon flew into the outskirts of the South Atlantic Anomaly, a zone of high space radiation. Bob Schaefer of the Johns Hopkins University Applied Physics Lab, who recently mapped the South Atlantic Anomaly from space, has a possible answer: “Earth’s magnetic field lines over central South America are nearly horizontal, which deflects lower energy vertically downward particles before they make it to your balloon’s detector.”
To explore these findings further, we are planning additional network launches every month from now on, adding new sites as often as possible. A launch planned from inside the Arctic Circle in January 2017 is especially noteworthy. Stay tuned for updates from the Intercontinental SWx Balloon Network.
Cosmic Rays in the Atmosphere
Updated: Sept. 29 2016 // Next Flight: Oct. 1, 2016
Sept. 20, 2016: Readers, thank you for your patience while we continue to develop this new section of Spaceweather.com. We’ve been working to streamline our data reduction, allowing us to post results from balloon flights much more rapidly, and we have developed a new data product, shown here:
This plot displays radiation measurements not only in the stratosphere, but also at aviation altitudes. Dose rates are expessed as multiples of sea level. For instance, we see that boarding a plane that flies at 25,000 feet exposes passengers to dose rates ~10x higher than sea level. At 40,000 feet, the multiplier is closer to 50x. These measurements are made by our usual cosmic ray payload as it passes through aviation altitudes en route to the stratosphere over California.
What is this all about? 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. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Our latest measurements show that cosmic rays are intensifying, with an increase of more than 12% since 2015:
Why are cosmic rays intensifying? The main reason is the sun. Solar storm clouds such as coronal mass ejections (CMEs) sweep aside cosmic rays when they pass by Earth. During Solar Maximum, CMEs are abundant and cosmic rays are held at bay. Now, however, the solar cycle is swinging toward Solar Minimum, allowing cosmic rays to return. Another reason could be the weakening of Earth’s magnetic field, which helps protect us from deep-space radiation.
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 data points in the graph above correspond to the peak of the Reneger-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth’s atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.
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 Oct. 11, 2016, the network reported 30 fireballs.
(25 sporadics, 2 Southern Taurids, 2 October delta Aurigids, 1 Orionid)
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 October 11, 2016 there were 1733 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.
speed: 391.2 km/sec
density: 6.7 protons/cm3
explanation | more data
Updated: Today at 1947 UTX-ray Solar Flares
6-hr max: B4 1320 UT Oct11
24-hr: B4 1320 UT Oct11
explanation | more data
Updated: Today at: 1900 UTDaily Sun: 11 Oct 16All of these sunspots are quiet and stable. Solar flare activity remains very low. Credit: SDO/HMI
Sunspot number: 64
What is the sunspot number?
Updated 11 Oct 2016
Current Stretch: 0 days
2016 total: 21 days (8%)
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 11 Oct 2016
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/OvationPlanetary K-index
Now: Kp= 0 quiet
24-hr max: Kp= 1 quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 5.7 nT
Bz: 3.8 nT north
explanation | more data
Updated: Today at 1946 UTCoronal Holes: 11 Oct 16
There are no large coronal holes on the Earthside of the sun. Credit: NASA/SDO.Noctilucent Clouds NASA’s AIM spacecraft has suffered an anomaly, and a software patch is required to fix it. As a result, current noctilucent cloud images will not return until late September 2016.
Switch view: Europe, USA, Asia, PolarUpdated at: 08-06-2016 16:55:02
Updated at: 2016 Oct 10 2200 UTC
Probabilities for significant disturbances in Earth’s magnetic field are given for three activity levels: active, minor storm, severe stormUpdated at: 2016 Oct 10 2200 UTCMid-latitudes