Solar minimum is here - but even now strangely beautiful auroras are dancing around the poles. Deep inside the Arctic Circle, the expert guides of Aurora Holidays in Utsjoki, Finland, can help you chase them. Book now! | | |
SOLAR WIND, INCOMING: A southern hole in the sun's atmosphere is facing Earth and spewing a stream of solar wind in our direction. Estimated time of arrival: April 3rd. Minor geomagnetic storms and Arctic auroras are possible when the gaseous material arrives. Aurora alerts: SMS text, email.
SOMETHING NEW ON THE SUN: A new sunspot is growing in the sun's northern hemisphere. Provisionally numbered AR2737, it is inset in this magnetic map of the sun from NASA's Solar Dynamics Observatory:
Sunspots are, essentially, islands of magnetism floating on the surface of the sun. Like all magnets they have poles, + and -. Sunspot AR2737 has a simple bipolar magnetic structure that identifies it as a member of old Solar Cycle 24.
There is a hint of a third pole (-) growing in this sunspot. If it continues to develop, creating a mixture of magnetic polarities, the region could become active. Mixed-polarity magnetic fields can criss, cross, and explode--a process known as "magnetic reconnection" underlying solar flares. So far, however, AR2737 is quiet.
Realtime Space Weather Photo Gallery
DEEP-SKY AURORAS IN THE USA: On March 31st, a minor stream of solar wind buffeted Earth's magnetic field. The gentle pressure was just enough to spark faint auroras over the US-Canadian border--pale and barely visible to the human eye, but an easy target for digital cameras. Kevin Palmer photographed the display from Lake DeSmet, Wyoming:
"I did not expect to see any auroras last night, so this was a pleasant surprise," says Palmer.
Brendan Lawrence of Kinsey, Montana, saw them, too. "I noticed the northern sky looking a bit brighter than usual," says Lawrance. "A 20-second exposure using my Nikon D800 confirmed that the aurora borealis was indeed visible all the way into southeastern Montana!"
These are called "deep sky auroras" because like other deep-sky objects (e.g., galaxies and nebulae) they are best seen using optics and timed exposures. More of them could be in the offing. A solar wind stream is approaching Earth and expected to arrive on April 3rd or 4th. A nearly-new Moon on those dates will make the night sky dark enough for long exposures. Photographers, grab your cameras and be alert for auroras.
A note to Spaceweather ALERT subscribers: Deep-sky auroras occur mainly during weak geomagnetic storms. To maximize your chances of photographing the phenomenon, sign up for the Pro Plan of Space Weather Alerts. When you receive a text message saying that the K-index is 4 or 5, deep sky auroras may be overhead.
Realtime Aurora Photo Gallery
A GIFT FROM THE EDGE OF SPACE: On August 16, 2018, the students of Earth to Sky Calculus launched a cosmic ray balloon to the stratosphere. This laser-etched Moon cube went along for the ride, ascending to an altitude of 101,140 feet:
You can have it for $119.95. The students are selling these cubes as a fund-raiser for their cosmic ray ballooning program. It's an authentic representation of the Moon, with all of the craters, mountains and lava plains accurately portrayed.
Each Moon-cube comes with a unique gift card showing the item floating at the top of Earth's atmosphere. The interior of the card tells the story of the flight and confirms that this gift has been to the edge of space and back again.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
Realtime Space Weather 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 Mar. 31, 2019, the network reported 6 fireballs.
(6 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 March 31, 2019 there were 1967 potentially hazardous asteroids.
|
Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
2019 FU1 | 2019-Mar-26 | 2 LD | 19.9 | 12 |
2019 FK1 | 2019-Mar-26 | 8.3 LD | 9.2 | 32 |
2019 EN | 2019-Mar-27 | 9.7 LD | 15.2 | 205 |
2019 FC1 | 2019-Mar-28 | 0.3 LD | 25.9 | 27 |
2019 FX | 2019-Mar-28 | 5.4 LD | 5 | 24 |
2019 FW | 2019-Mar-29 | 8.1 LD | 6.2 | 22 |
2019 FB1 | 2019-Mar-31 | 1.5 LD | 8.2 | 10 |
2019 FN1 | 2019-Apr-02 | 8.5 LD | 9 | 14 |
2016 GE1 | 2019-Apr-04 | 3.9 LD | 10.1 | 17 |
2019 FV | 2019-Apr-06 | 15 LD | 7.7 | 59 |
2019 FU | 2019-Apr-09 | 5.3 LD | 14.2 | 86 |
2014 UR | 2019-Apr-09 | 13 LD | 4.6 | 17 |
2016 GW221 | 2019-Apr-09 | 10.1 LD | 5.3 | 39 |
2014 HD177 | 2019-Apr-10 | 6.1 LD | 14 | 102 |
2019 FO1 | 2019-Apr-13 | 14.4 LD | 9.7 | 28 |
2019 FH1 | 2019-Apr-13 | 18 LD | 3.8 | 32 |
2012 XO134 | 2019-Apr-18 | 14.8 LD | 11 | 56 |
522684 | 2019-Apr-19 | 19 LD | 11.5 | 214 |
2018 KK1 | 2019-May-05 | 13.9 LD | 13.9 | 71 |
2017 RC | 2019-May-09 | 14.5 LD | 10.6 | 9 |
2008 HS3 | 2019-May-09 | 14.6 LD | 5.3 | 162 |
2018 VX8 | 2019-May-12 | 6.2 LD | 15.5 | 118 |
2012 KT12 | 2019-May-18 | 3.3 LD | 3.9 | 20 |
2015 KQ18 | 2019-May-25 | 10.7 LD | 13.1 | 30 |
66391 | 2019-May-25 | 13.5 LD | 21.5 | 1780 |
2003 LH | 2019-May-28 | 15.6 LD | 7.4 | 32 |
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 |
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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