Looking for a far-out Mother's Day gift? Find something truly out of this world in the Earth to Sky Store. Space roses, Cosmic Reindeer, Arctic space pendants, and more!
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EXITING THE SOLAR WIND STREAM: Earth is beginning to exit a stream of solar wind that has sparked bright auroras around both poles in recent days. We're not out of the stream yet, though. NOAA forecasters estimate a 60% chance of minor G1-class geomagnetic storms on April 25th and 26th as the solar wind pressure slowly subsides. Free: Aurora Alerts
A QUAKE IN EARTH'S MAGNETIC FIELD: When a CME from the sun struck Earth on April 22nd, our planet's magnetic field reverberated from the impact. A day later, a stream of solar wind arrived, hit, and had the same effect. In Lancashire, England, a magnetometer operated by Stuart Green captured the quaking of Earth's magnetic field:
"The data clearly show when the relative calm was shattered on April 21st at around 16:30 (UT) when the CME struck, being quickly followed by fast flowing solar wind from a large and persistent coronal hole," says Green. "The rumblings have been continuing through the intervening days."
Vibrations in the magnetic field allow particles normally trapped in our planet's magnetosphere to rain down around the poles, igniting auroras. Thomas J. Spence was camping in the Boundary Waters Canoe Area of northern Minnesota on April 22nd when the sky suddenly lit up:
"I ventured into the BWCA less than 24 hours after the ice was gone from Kawihiwi Lake--and coincidentally not long after the CME impact," says Spence. "The aurora began soon after sunset and continued until first light. It was an incredible first spring trip into this amazing wilderness."
Realtime Aurora Photo Gallery
DRIPPING SUN MIRAGE: When a swimmer steps out of the sea, he or she naturally drips into the water below. This morning over the Mediterranean, the rising sun appeared to do the same thing. Mohamad Soltanolkotabi photographed the dripping orb from Mataro, Spain:
"The strange shape of the sun, known as the Omega Sun, is an atmospheric phenomena. The lower sun is not a reflection from the water," Soltanolkotabi explained. "It is a mirage caused by warm air and a strong temperature gradient just above the Mediterranean sea surface."
"The current sunspot AR2652 may also seen on the face of the sun," he points out.
Warning: Even when the low-hanging sun is dimmed by clouds or haze, it can still damage your eyes. Sunlight magnified by unfiltered optics is dangerously bright. If you chose to photograph the low sun, as Soltanolkotabi did, use the camera's LCD screen for safe viewfinding. Never look into the eyepiece of an unfiltered camera or telescope when the sun is in the field of view.
Realtime Space Weather Photo Gallery
THESE PENDANTS HAVE TOUCHED SPACE: These pendants have touched space--and returned to Earth in time for Mother's Day. On April 15, 2017, the students of Earth to Sky Calculus flew a payload-full of heart-shaped Venus pendants to the stratosphere onboard a high-altitude helium balloon. Here's one, 111,550 feet above the Sierras of central California:
These blue jewels make great Mother's Day gifts--and you have have one for $99.95. Each glittering pendant comes with a greeting card showing the jewelry in flight and telling the story of its journey to the stratosphere and back again.
More far-out Mother's Day gifts may be found in the Earth to Sky Store. All proceeds support atmospheric radiation monitoring and hands-on STEM education.
Realtime Aurora Photo Gallery
Realtime Comet 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 Apr. 25, 2017, the network reported 20 fireballs.
(16 sporadics, 4 April Lyrids)
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 April 25, 2017 there were 1799 potentially hazardous asteroids.
| |Recent & Upcoming Earth-asteroid encounters:
|Asteroid || |
|2017 HW2 || |
|2017 FE157 || |
|2017 HK1 || |
|2015 VD1 || |
|2012 EC || |
|2017 CS || |
|418094 || |
|2010 VB1 || |
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.
|471984 || |
| ||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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| ||fun to read, but should be taken with a grain of salt! Forecasts looking ahead more than a few days are often wrong. |
| ||from the NOAA Space Environment Center |
| ||the underlying science of space weather |
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