| | Switch to: Europe, USA, New Zealand, Antarctica Credit: NOAA/Ovation Planetary K-index Now: Kp= 4 unsettled 24-hr max: Kp= 4 unsettled explanation | more data Interplanetary Mag. Field Btotal: 4.1 nT Bz: -3.1 nT south more data: ACE, DSCOVR Updated: Today at 2351 UT Coronal Holes: 26 Dec 17 Earth is inside a stream of solar wind flowing from the indicated coronal hole.. Credit: SDO/AIA Noctilucent Clouds Latest images from NASA's AIM spacecraft show that the 2017 northern summer season for noctilucent clouds has finished. Switch view: Europe, USA, Asia, Polar Updated at: 12-26-2017 18:45:52 SPACE WEATHER NOAA Forecasts | | Updated at: 2017 Dec 26 2200 UTC FLARE | 0-24 hr | 24-48 hr | CLASS M | 01 % | 01 % | 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 Dec 26 2200 UTC Mid-latitudes | 0-24 hr | 24-48 hr | ACTIVE | 30 % | 10 % | MINOR | 05 % | 05 % | SEVERE | 01 % | 01 % | High latitudes | 0-24 hr | 24-48 hr | ACTIVE | 20 % | 20 % | MINOR | 25 % | 20 % | SEVERE | 20 % | 15 % | | | | | | | | | | | | All-inclusive Northern Lights trips in Tromsø, Norway. Small groups, big experiences! Highly qualified guides ensure unique and unforgettable adventures with a personal touch. Visit Explore the Arctic | | | EXITING THE SOLAR WIND STREAM: Earth is exiting a fast-moving stream of solar wind that lit up the Arctic Circle with auroras on Dec. 25th. As the solar wind subsides, NOAA forecasters have reduced the odds of polar geomagnetic storms on Dec. 26th to only 25%. Free: Aurora alerts. POLAR STRATOSPHERIC CLOUDS: Are we heading for a outbreak of polar stratospheric clouds (PSCs)? Winter has barely begun, yet sky watchers around the Arctic Circle have already witnessed several colorful apparitions. Moreover, the clouds appear to be spreading to lower latitudes. On Dec. 23rd, Alan C Tough saw their aurora-like colors peeking through a gap in ordinary rainclouds over Elgin, Scotland, a full 10 degrees below the Arctic Circle: The next night, Dec. 24th, Ivo Dinsbergs saw them from Riga, Latvia--like Tough's sighting, they were 10 degrees below the Arctic Circle. "Type I PSCs are not very often visible at these latitudes," says Dinsbergs. "The last time when they were observed in Latvia was 7 years ago." Polar stratospheric clouds are a sign of extraordinarily cold temperatures in the stratosphere. Colorful Type II PSCs require temperatures around -85º C to form. The stratosphere is drier than almost any desert on Earth. Only when the air up there becomes profoundly cold do widely-spaced water molecules coalesce to form ice crystals--the "stuff" of PSCs. High-altitude sunlight shining through these ice particles produces the clouds' characteristic bright iridescent colors. In recent years, some photographers sending their images to Spaceweather.com have expressed their impression that PSCs are appearing earlier in winter and spreading over a greater range of latitudes. So far, the polar stratospheric clouds of 2017-2018 are conforming to those reports. Stay tuned for more sightings as northern winter deepens. Realtime PSC Photo Gallery GREEN CHRISTMAS: Some people wish for a White Christmas. In Abisko, Sweden, aurora tour guide Sarah Skinner was hoping for a different color: Green. "I got my wish!" she says. "I headed out with my Lights over Lapland group on Christmas night, and we were bathed in auroras for more than 3 hours." At the peak of the display, the whole landscape turned green: "I will never forget this tour," she says. "There were bright auroras overhead, one guest enjoying their birthday and, to top it off, a marriage proposal. Christmas doesn't get much better than that!" The reason for the display, and possibly the marriage proposal, was the solar wind. A stream of gaseous material flowing from a hole in the sun's atmosphere hit Earth on Christmas Eve, causing energetic particles from space to rain down on our planet's upper atmosphere. Green auroras were observed all around the Arctic Circle. Free: Aurora alerts. Realtime Aurora Photo Gallery EXTENDED! STUDENT CHRISTMAS SPECIAL: For the holiday season only, we're reducing the cost of payload space on Earth to Sky Calculus balloons from $500 to only $299. Buy a ticket to space on or before Jan. 1st and your student can send an experiment, photo, or keepsake item to the stratosphere, completely supported by an Earth to Sky Calculus launch and recovery team. This is not only a great Christmas gift, but also a good kickstarter for science fair projects. Experiments will be flown and returned along with video footage, GPS tracking, temperature, pressure, altimetry and radiation data. To take advantage of the discounted rate, payment must be received before Jan. 1st. However, the flight can take place at any time in the next 12 months. Conditions: No mammals. Plants and non-pathogenic microbes are allowed. Generally speaking, experiments should weigh less than a few hundred grams and occupy a volume less than that of a school lunchbox. A brainstorming session is included with each certificate. Dr. Tony Phillips and other members of the Earth to Sky team will chat with recipients to help them craft an experiment that will work in the harsh environment of the stratosphere. Far Out Gifts: Earth to Sky Store All proceeds support hands-on STEM education Realtime Space Weather 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 Dec. 26, 2017, the network reported 20 fireballs. (18 sporadics, 2 December Leonis Minorids) 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 December 26, 2017 there were 1872 potentially hazardous asteroids. | Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) | 2017 YN1 | 2017-Dec-20 | 8.4 LD | 8.1 | 21 | 2017 YT1 | 2017-Dec-20 | 8 LD | 21.1 | 39 | 2017 YP1 | 2017-Dec-20 | 5.7 LD | 13.6 | 26 | 2017 YO3 | 2017-Dec-20 | 2.1 LD | 8.2 | 8 | 2017 WX12 | 2017-Dec-21 | 10 LD | 11.4 | 135 | 2017 XR60 | 2017-Dec-21 | 13 LD | 6.2 | 48 | 2017 XQ60 | 2017-Dec-21 | 13.4 LD | 15.7 | 46 | 2017 YE | 2017-Dec-22 | 2.9 LD | 4.7 | 7 | 2017 TS3 | 2017-Dec-22 | 18.1 LD | 10.2 | 136 | 418849 | 2017-Dec-22 | 15.3 LD | 17.4 | 257 | 2015 YQ1 | 2017-Dec-22 | 17.3 LD | 11.1 | 9 | 2017 YW | 2017-Dec-22 | 7.9 LD | 8.3 | 16 | 2017 YS1 | 2017-Dec-24 | 1.9 LD | 3.4 | 6 | 2017 WZ14 | 2017-Dec-24 | 7.6 LD | 4.9 | 34 | 2017 YR3 | 2017-Dec-25 | 8.5 LD | 6.5 | 30 | 2017 YQ1 | 2017-Dec-26 | 5.1 LD | 21.1 | 43 | 2017 YD2 | 2017-Dec-27 | 2.2 LD | 8.3 | 6 | 2017 XG1 | 2017-Dec-29 | 16.3 LD | 9.9 | 38 | 2017 QL33 | 2017-Dec-30 | 13.3 LD | 8.2 | 193 | 2017 YU1 | 2017-Dec-30 | 7.8 LD | 7.6 | 20 | 2017 YD | 2018-Jan-01 | 19.1 LD | 4.1 | 30 | 2015 RT1 | 2018-Jan-02 | 19.7 LD | 9 | 30 | 2017 XT61 | 2018-Jan-08 | 11.4 LD | 10.8 | 83 | 2004 FH | 2018-Jan-10 | 20 LD | 8.5 | 26 | 2017 YU3 | 2018-Jan-14 | 18.1 LD | 13.2 | 53 | 306383 | 2018-Jan-22 | 14.4 LD | 17.4 | 178 | 2002 CB19 | 2018-Feb-02 | 10.5 LD | 15.6 | 36 | 276033 | 2018-Feb-04 | 11 LD | 34 | 646 | 2015 BN509 | 2018-Feb-09 | 12.9 LD | 17.7 | 257 | 1991 VG | 2018-Feb-11 | 18.4 LD | 2.1 | 7 | 2014 WQ202 | 2018-Feb-11 | 15.1 LD | 19.8 | 62 | 2016 CO246 | 2018-Feb-22 | 15.3 LD | 5.4 | 21 | 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 13% 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 | | 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 | | Reviews here can help you to pick up best memory foam mattresses. | | These links help Spaceweather.com stay online. Thank you to our supporters! | | | | | | | | | | | | ©2017 Spaceweather.com. All rights reserved. This site is penned daily by Dr. Tony Phillips. | |