| Marianne's Arctic Xpress supports World Cancer Day by donating 50% of the price paid on all bookings Feb. 3-5 to cancer research. Arctic clothing and semi-pro cameras included. Groups of 2 to 8 welcome. Book Now | |
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SUNSET SKY SHOW: When the sun goes down tonight, step outside and look southwest. The crescent Moon is joining bright Venus and red Mars to form a triangle in the sunset sky. Try to catch them before the sky fades to black. A conjunction of bright planets framed by twilight blue is extra beautiful.
Sky maps:Jan. 30,
31.
A HOLE IN THE SUN'S ATMOSPHERE: A large, canyon-shaped hole has opened in the sun's atmosphere, and it is spewing a stream of solar wind directly toward Earth. NASA's Solar Dynamics Observatory photographed the structure, which stretches more than halfway across the face of the sun:
This is a "coronal hole" (CH)--a region where the sun's magnetic field opens up and allows solar wind to escape. NASA's STEREO spacecraft recently sampled the stream flowing from this hole and the velocity was unusually high: nearly 750 km/s. Such a fast-moving stream will likely spark Arctic auroras when it arrives on
Feb. 1st. Stay tuned!
Free: Aurora alerts.
A VISIT FROM THE ANCESTORS: "Things are getting spooky around the Arctic Circle," reports Markus Varik. Last night, he photographed this apparition over Tromsø, Norway:
"According to the local indigenous Sami people, Northern Lights represent the souls of ancestors. When teased, the spirits descend and pick up the teaser--never to be seen again," says Varik. "Working as a seasoned Northern Lights guide, I have done my fair share of teasing. This time, luckily, I was released after a short inspection."
In addition to teasing, another factor may have played a role in conjuring these auroras: Earth passed through a fold in the
heliospheric current sheet. Many people have never heard of the heliospheric current sheet, yet 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. Earth dips in and out of it all the time. These crossings are called "solar sector boundary crossings," and they have been known to spark bright Arctic lights.
FAR-OUT VALENTINE'S GIFT: Nothing says "I love you" like a bear from space. To raise money for their
cosmic ray research program, the students of Earth to Sky Calculus have flown a payload-full of Valentine's bears to the edge of space. This was a special flight, timed to photograph the bears at sunset in the stratosphere, wrapped in the romantic light of the fading sun 98,000 feet above Earth's surface:
You can
have one for $49.95. Each bear comes with a Valentine's card showing the bears in flight and telling the story of their trip to the stratosphere.
More far-out Valentine's gifts may be found in the
Earth to Sky store. All proceeds support cosmic ray balloon flights and STEM education.
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. 31, 2017, the network reported 29 fireballs.
(29 sporadics)
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 31, 2017 there were 1770 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 |
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.
| | 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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| | the underlying science of space weather |
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