Lights Over Lapland has a brand-new website full of exciting adventures in Abisko National Park, Sweden! Take a look at our aurora activities and book your once-in-a-lifetime trip with us today!
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SOLAR MINIMUM CONDITIONS ARE IN EFFECT: The sun has been without sunspots for 213 days in 2018--that is, 60% of the time. To find a similar stretch of blank suns, you have to go back to 2009 when the sun was experiencing the deepest solar minimum in a century. Solar minimum has returned, bringing extra cosmic rays, long-lasting holes in the sun's atmosphere, and strangely pink auroras. Free: Aurora Alerts.
ULTIMA THULE'S FIRST PUZZLE: NASA's New Horizons spacecraft is 12 million km from Ultima Thule and closing fast. On New Year's Day, it will fly by the mysterious Kuiper Belt Object three times closer than it buzzed Pluto in 2015 revealing ... no one knows what. In fact, the mysteries have already begun.
Long range images of Ultima Thule reveal that it has no light curve. In other words, its brightness is constant.
Above: An artist's concept of Ultima Thule, a double-lobed object in the Kuiper Belt
"It's really a puzzle," says New Horizons Principal Investigator Alan Stern of the Southwest Research Institute. And here's why:
Last year, astronomers watched a distant star pass behind Ultima Thule. Starlight winked in and out in a pattern suggesting an elongated object with two bulbous lobes. Ultima Thule could be a binary system. You would expect the reflected brightness of such an object to vary as it rotates in the sunlight. Yet Ultima Thule does not behave that way.
What's going on? New Horizons science team members have different ideas. "It's possible that Ultima's rotation pole is aimed almost right at the spacecraft," speculates Marc Buie of the Southwest Research Institute. Such an alignment, however, is unlikely.
"Another explanation," says the SETI Institute's Mark Showalter, "is that Ultima may be surrounded by a cloud of dust that obscures its light curve--much the same way that a comet's coma often overwhelms the light reflected by its central nucleus."
"A more bizarre scenario is one in which Ultima is surrounded by many tiny tumbling moons," suggests University of Virginia's Anne Verbiscer, a New Horizons assistant project scientist. "If each moon has its own light curve, then together they could create a jumbled superposition of light curves that make it look to New Horizons like Ultima has a small light curve."
"It's hard to say which of these ideas is right," Stern says. "We'll get to the bottom of this puzzle soon – New Horizons will swoop over Ultima and take high-resolution images on Dec. 31 and Jan. 1, and the first of those images will be available on Earth just a day later. When we see those high--resolution images, we'll know the answer to Ultima's vexing first puzzle. Stay tuned!"
Realtime Space Weather Photo Gallery
BUY A TICKET TO THE EDGE OF SPACE: Need a last-minute Christmas gift? Consider this: 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 an edge of space gift certificate before Dec. 25th and you 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 Dec. 25th. However, the flight can take place at any time in the next 12 months. You'll receive the ticket electronically so you can print it out and give it as a Christmas Day gift.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
Realtime Comet Photo Gallery
Realtime Aurora 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. 22, 2018, the network reported 12 fireballs.
(10 sporadics, 1 Comae Berenicid, 1 December Leonis Minorid)
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 23, 2018 there were 1947 potentially hazardous asteroids.
| |Recent & Upcoming Earth-asteroid encounters:
|Asteroid || |
|2018 XR4 || |
|2018 XC4 || |
|2017 XQ60 || |
|163899 || |
|418849 || |
|2018 XN5 || |
|2018 XE4 || |
|2014 AD16 || |
|2018 XO4 || |
|2016 AZ8 || |
|2013 YM2 || |
|2018 XN || |
|2013 CW32 || |
|2013 RV9 || |
|2017 PV25 || |
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.
|455176 || |
| ||Cosmic Rays in the Atmosphere |
SOMETHING NEW! We have developed a new predictive model of aviation radiation. It's called E-RAD--short for Empirical RADiation model. We are constantly flying radiation sensors onboard airplanes over the US and and around the world, so far collecting more than 22,000 gps-tagged radiation measurements. Using this unique dataset, we can predict the dosage on any flight over the USA with an error no worse than 15%.
E-RAD lets us do something new: Every day we monitor approximately 1400 flights criss-crossing the 10 busiest routes in the continental USA. Typically, this includes more than 80,000 passengers per day. E-RAD calculates the radiation exposure for every single flight.
The Hot Flights Table is a daily summary of these calculations. It shows the 5 charter flights with the highest dose rates; the 5 commercial flights with the highest dose rates; 5 commercial flights with near-average dose rates; and the 5 commercial flights with the lowest dose rates. Passengers typically experience dose rates that are 20 to 70 times higher than natural radiation at sea level.
To measure radiation on airplanes, we use the same sensors we fly to the stratosphere onboard Earth to Sky Calculus cosmic ray balloons: neutron bubble chambers and X-ray/gamma-ray Geiger tubes sensitive to energies between 10 keV and 20 MeV. These energies span the range of medical X-ray machines and airport security scanners.
Column definitions: (1) The flight number; (2) The maximum dose rate during the flight, expressed in units of natural radiation at sea level; (3) The maximum altitude of the plane in feet above sea level; (4) Departure city; (5) Arrival city; (6) Duration of the flight.
SPACE WEATHER BALLOON DATA: 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 18% since 2015:
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.
En route to the stratosphere, our sensors also pass through aviation altitudes:
In this plot, 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.
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.
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 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 |
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