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SUNSPOTS VANISH: Two days ago, a pair of tiny fading sunspots vanished, leaving the face of the sun blank. Spotless suns are a sign that Solar Minimum is approaching. During times like this, solar flares stop, but other forms of solar activity continue. Cosmic rays, for instance, become more intense, while solar wind streams spark beautiful "Solar Minimum auroras." Speaking of which, read on...
SOLAR MINIMUM AURORAS: Today, a stream of solar wind flowing from a hole in the sun's atmosphere is grazing Earth's magnetic field. Compared to other solar wind streams that have hit Earth in recent weeks, the glancing pressure of this stream is relatively weak. Nevertheless, it is sufficient for Arctic auroras. Last night in northern Finland, Dan A. Steinbakk watched a luminous green spray envelop the Moon:
"Many people believe that a full Moon will ruin the view of auroras," says Steinbakk. "Well, up here that is not true. It will actually make the pictures look more awesome, because the Moon lights up the landscape around you. Auroras can be all over the sky, even dancing around the Moon!"
Earth will probably exit this stream of solar wind by Nov. 4th. (Even now we are barely inside it.) Until then, Arctic sky watchers should remain alert for auroras mixed with moonlight. Free: Aurora Alerts.
Realtime Aurora Photo Gallery
A METEOR MELTS AWAY: On the night of Oct. 26th, sky watchers in Japan witnessed a fireball tearing through the belt of Orion. "It was yellow and very bright," reports Yasushi Aoshima, who captured the dramatic disintegration in a series of rapid-fire photos. Click to watch the meteor melt away:
The swirling wisps in Aoshima's photos are the meteoroid's smokey remains, stretched and twisted by high altitude winds in the upper atmosphere. "I classify this as a 'melting-away type meteor,' says Aoshima.
Another group in Japan, the SonotaCo Meteor Network, used images from multiple cameras to calculate the meteoroid's orbit. They found that it came from beyond the orbit of Mars, a random piece of rocky space debris in the Asteroid Belt. Possibly nudged out of its orbit by the gravity of Jupiter or a collision with a neighboring meteoroid, it fell toward Earth and made a beautiful yellow fireball over Japan.
More fireballs are in the offing. Right now, Earth is passing through a broad, sparse stream of debris from Comet Encke, source of the annual Taurid meteor shower. Taurid meteor rates are typically low, only a handful per hour, but the shower compensates for that by being rich in fireballs. Encke's gravelly debris tends to produce beautifully bright meteors like the one Aoshima recorded on Oct. 26th. The northern branch of the Taurid meteor shower peaks on Nov. 10-11.
Realtime Space Weather Photo Gallery
THIS WATCH FLEW TO SPACE ... AND KEPT ON TICKING: On Aug. 21, 2017, during the Great American Solar Eclipse, the students of Earth to Sky Calculus launched 11 space weather balloons from the path of totality. They soared into the stratosphere, photographing the shadow of the Moon more than 100,000 feet above Earth's surface. As a fundraiser, one of the balloons carried this wristwatch:
With the sun, Earth, and Moon perfectly aligned, the watch entered the space-cold shadow of the Moon … and kept on ticking! Watch the video. It survived temperatures lower than -49 C and cosmic ray dose rates more than 100 times sea level.
You can have one for $79.95. Each timepiece comes with a unique gift card showing the watch floating at the top of Earth's atmosphere and touching the shadow of the Moon. 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 proceeds support hands-on STEM education
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 Nov. 3, 2017, the network reported 12 fireballs.
(9 sporadics, 2 Northern Taurids, 1 Orionid)
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 November 3, 2017 there were 1853 potentially hazardous asteroids.
|
Recent & Upcoming Earth-asteroid encounters: Asteroid | Date(UT) | Miss Distance | Velocity (km/s) | Diameter (m) |
2017 UV7 | 2017-Oct-29 | 6.1 LD | 12.5 | 18 |
2017 UA6 | 2017-Oct-29 | 4 LD | 15 | 26 |
2017 UL8 | 2017-Oct-30 | 1.2 LD | 10.5 | 8 |
2017 UK8 | 2017-Oct-30 | 0.6 LD | 14.1 | 8 |
2017 UL43 | 2017-Oct-30 | 14.2 LD | 10.4 | 18 |
2017 UJ6 | 2017-Oct-30 | 5.5 LD | 11.3 | 18 |
2017 UO43 | 2017-Oct-31 | 6.6 LD | 5.7 | 9 |
2017 TZ4 | 2017-Oct-31 | 19.3 LD | 13.1 | 96 |
2003 UV11 | 2017-Oct-31 | 15 LD | 24.5 | 447 |
2017 UP6 | 2017-Oct-31 | 15.1 LD | 11.6 | 22 |
2017 UO2 | 2017-Oct-31 | 11 LD | 8.7 | 22 |
2017 UD43 | 2017-Nov-01 | 4.7 LD | 8.8 | 7 |
2017 UL44 | 2017-Nov-03 | 13.3 LD | 15.4 | 64 |
2017 UX42 | 2017-Nov-05 | 10.5 LD | 2.6 | 7 |
2017 US7 | 2017-Nov-05 | 7.1 LD | 8.8 | 13 |
2017 UJ7 | 2017-Nov-05 | 16.8 LD | 13 | 28 |
2017 UJ43 | 2017-Nov-05 | 4.6 LD | 7.3 | 9 |
2013 BD74 | 2017-Nov-06 | 10.6 LD | 9 | 51 |
2017 TZ3 | 2017-Nov-09 | 10.3 LD | 8.7 | 39 |
444584 | 2017-Nov-17 | 8.7 LD | 14.8 | 324 |
2008 WM61 | 2017-Dec-03 | 3.8 LD | 4.7 | 16 |
2015 XX169 | 2017-Dec-14 | 9.7 LD | 6.3 | 11 |
2011 YD29 | 2017-Dec-19 | 17.6 LD | 7.7 | 20 |
2006 XY | 2017-Dec-20 | 6.5 LD | 5 | 56 |
2017 TS3 | 2017-Dec-22 | 18.2 LD | 10.2 | 133 |
418849 | 2017-Dec-22 | 15.3 LD | 17.4 | 257 |
2015 YQ1 | 2017-Dec-22 | 17.3 LD | 11.1 | 9 |
2017 QL33 | 2017-Dec-30 | 13.3 LD | 8.2 | 191 |
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 |
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