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.
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