SOLAR WIND APPROACHES EARTH: A stream of solar wind is about to hit Earth's magnetic field. Estimated time of arrival: Feb. 20th. The gaseous material is flowing from a trans-equatorial fissure in the sun's atmosphere. Arctic sky watchers can expect minor geomagnetic storms and auroras mixed with bright moonlight when the fast-moving stream arrives. Aurora Alerts: SMS text, email.
MERCURY AT SUNSET: Tonight, right after the sun goes down, step outside and look west into the sunset. "Mercury is returning to the evening sky!" reports Piotr Majewski of Piwnice, Poland. He took this picture of the innermost planet shining just above the 32-meter radio telescope at the Toruń Centre for Astronomy:
Mercury is normally overwhelmed by the sun, but as February comes to a close, Mercury is emerging from the glare. The view will improve every night for the rest of the month as the planet climbs higher in the sunset sky, reaching a maximum elongation (distance from the sun) of 18 degrees on Feb. 27-28.
The best time to look is 30 to 45 minutes after sunset. Mercury often has a pink or orange hue, as it is filtered by the same low atmosphere that gives the sunset its colors. Scanning the horizon with binoculars can help you locate it. Once found, Mercury is easy to see with the unaided eye.
Realtime Space Weather Photo Gallery
SUPER SNOW MOON: There's a full Moon tonight--the biggest and brightest of 2019. According to folklore, it's the "Snow Moon." According to science, it's a Super Snow Moon, inflated in size and luminosity because it occurs on the nearside of the Moon's orbit.
Above: The perigee Moon of Feb. 19, 2019 vs the eclipsed apogee Moon of Jul. 27, 2018. Photo credit: Nunzio Micale of Vieste, Italia
Full moons vary in size because the Moon's orbit is not a circle, it's an ellipse: diagram. One side of the Moon's orbit, called "perigee," is 50,000 km closer to Earth than the other side, "apogee." Today's "supermoon" becomes full just 6 hours away from perigee, a coincidence that makes it almost 8% wider and 16% brighter than an average full Moon.
But will we be able to tell the difference just by looking? A 16% difference in brightness can easily be masked by clouds or the glare of urban lights. Also, there are no rulers floating in the sky to measure lunar diameters. Hanging high overhead with no reference points to provide a sense of scale, one full Moon looks much like any other. They're all beautiful. Monitor the realtime gallery for photos.
Realtime Space Weather Photo Gallery
SPACE WEATHER ALERTS: Spaceweather.com is proud to announce our new and improved space weather alert system. Sign up now and you'll never miss another solar storm in 2019. Subscribers receive instant text messages when there are solar flares, geomagnetic storms, and CMEs about to strike Earth. And if you sign up for the PRO PLAN, you'll receive a type of alert available no where else--"Magnetic Crack" alerts. Keep reading after the graphic to learn more:
PRO PLAN subscribers get a text message whenever a crack is opening in Earth's magnetosphere. Magnetic cracks are caused by south-pointing magnetic fields ("BsubZ") in the solar wind, which partially cancel Earth's magnetic defenses. Solar wind pours in through these cracks to fuel bright auroras and geomagnetic storms. Veteran aurora chasers know that watching "BsubZ" is the best way to anticipate geomagnetic activity. Now your cell phone can do this job for you, alerting you when cracks are forming in the invisible magnetic field overhead.
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