| | Switch to: Europe, USA, New Zealand, Antarctica Credit: NOAA/Ovation Planetary K-index Now: Kp= 1 quiet 24-hr max: Kp= 2 quiet explanation | more data Interplanetary Mag. Field Btotal: 4.1 nT Bz: -1.1 nT south more data: ACE, DSCOVR Updated: Today at 0004 UT Coronal Holes: 16 Apr 17 Solar wind flowing from the indicated coronal hole should reach Earth on April 16-17. Credit: NASA/SDO. Noctilucent Clouds The southern season for noctilucent clouds began on Nov. 17, 2016. Come back to this spot every day to see the "daily daisy" from NASA's AIM spacecraft, which is monitoring the dance of electric-blue around the Antarctic Circle. Switch view: Ross Ice Shelf, Antarctic Peninsula, East Antarctica, Polar Updated at: 02-24-2017 17:55:02 SPACE WEATHER NOAA Forecasts | | Updated at: 2017 Apr 16 2200 UTC FLARE | 0-24 hr | 24-48 hr | CLASS M | 05 % | 05 % | CLASS X | 01 % | 01 % | Geomagnetic Storms: Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm Updated at: 2017 Apr 16 2200 UTC Mid-latitudes | 0-24 hr | 24-48 hr | ACTIVE | 40 % | 40 % | MINOR | 20 % | 20 % | SEVERE | 01 % | 01 % | High latitudes | 0-24 hr | 24-48 hr | ACTIVE | 10 % | 10 % | MINOR | 20 % | 25 % | SEVERE | 55 % | 55 % | | | | | | | | | | | | 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! | | | ASTEROID FLYBY: Approaching from the direction of the sun, mountain-sized asteroid 2015 JO25 will fly past Earth on April 19th approximately 1.8 million km away. NASA says there is no danger of a collision. This unusually bright space rock is about twice as reflective as the Moon. Amateur astronomers may be able to see it in backyard telescopes as a magnitude 11 speck of light during and after the flyby. Got an image? Submit it here. SOLAR WIND STREAM APPROACHES EARTH: A hole has opened in the sun's atmosphere and it is directly facing Earth. NASA's Solar Dynamics Observatory photographed the structure bisecting the solar disk on April 16th: This is a "coronal hole"--a place where the sun's magnetic field opens up and allows solar wind to escape. Solar wind emerging from this hole could reach Earth as early as April 17th. NOAA forecasters estimate a 55% chance of polar geomagnetic storms when the solar wind arrives on April 17-18. Arctic twilight will mute the visibility of Northern Lights, but might not overwhelm them completely if the auroras are bright. Monitor the aurora gallery for sightings. Free: Aurora Alerts. Realtime Aurora Photo Gallery DOUBLE RAINBOW: Whenever you see one rainbow, look for another, because rainbows always come in pairs. Consider this example, photographed by Kamila Mazurkiewicz Osiak of Trzcianki, Poland, on April 13th: "This huge double rainbow appeared after an intense rainstorm passed through our area," says Osiak. "It was raining so hard, it looked like the clouds were walking on the ground." The bright inner rainbow is the primary bow, caused by sunbeams reflecting once inside falling raindrops. It's the bow you usually see. The less-bright outer rainbow is the secondary bow, caused by sunbeams reflecting twice inside raindrops. Secondary bows often go unnoticed, because they are usually very faint, but they are always there. In Osiak's case, "you couldn't miss it," she says. Bright sunlight lancing through the clearing clouds struck droplet-laden air behind the retreating storm, resulting in an unusually intense secondary bow. Realtime Space Weather 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. 16, 2017, the network reported 3 fireballs. (3 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 April 16, 2017 there were 11 potentially hazardous asteroids. | Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) | 2017 GO4 | 2017-Apr-15 | 13.8 LD | 6 | 34 | 2014 UR | 2017-Apr-19 | 18.8 LD | 4.4 | 17 | 2014 JO25 | 2017-Apr-19 | 4.6 LD | 33.6 | 852 | 2017 GL4 | 2017-Apr-20 | 17.5 LD | 7.4 | 22 | 2017 GM4 | 2017-Apr-20 | 13.1 LD | 16.6 | 143 | 2017 FH101 | 2017-Apr-24 | 18.8 LD | 9.9 | 103 | 2017 FE157 | 2017-Apr-29 | 18.6 LD | 8.6 | 64 | 2015 VD1 | 2017-May-07 | 18.2 LD | 10.5 | 34 | 2012 EC | 2017-May-16 | 19.5 LD | 4.5 | 74 | 2017 CS | 2017-May-29 | 8 LD | 9.1 | 468 | 418094 | 2017-Jun-01 | 8 LD | 23.2 | 490 | 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." 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