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Thursday, January 26, 2012



Venus, Jupiter, and Mars — three of our four closest planetary neighbors — adorn the evening sky as the new year breaks. Venus is the dazzling "evening star" in the west at sunset, with only slightly fainter Jupiter high in the south at the same hour. Orange Mars rises by around 11 p.m. as January opens, but about two hours earlier at month's end.

January 26, 2012
The crescent Moon and the dazzling "evening star" stand high in the west-southwest as night falls this evening. Venus, the evening star, is to the lower left of the Moon.

January 27, 2012
Leo, the lion, springs into the evening sky this month. Its brightest star, Regulus, rises around 7:30 or 8 p.m., with the body of the lion following over the next couple of hours. Denebola, the star that marks its tail, rises around 10 p.m.

January 28, 2012
The big dog trots across the southern sky on winter nights — the constellation Canis Major. It is escorted by the little dog, Canis Minor, which is to the upper left of the big dog in early evening, marked by its brightest star, Procyon.

SUNSET PLANETS: For the second day in a row, Venus and the crescent Moon are shining together in the sunset sky. Look west at the end of the day for a beautiful view.

MORE SOLAR ACTIVITY: Sunspot AR1402, the source of this week's powerful M9-class solar flare, is acting up again. On Jan. 26th between 0100 UT and 0600 UT, a sequence of C-class magnetic eruptions around the active region hurled a bright coronal mass ejection over the sun's north pole. The cloud is not heading toward Earth, at least not directly. This and future eruptions from AR1402 are unlikely to be geoeffective as the sunspot is turning away from our planet. By week's end it will be on the far side of the sun, blasting its CMEs toward planets on the opposite side of the solar system.

When an intense solar flare erupted from the sun this week, it exploded from a busy sunspot on the surface of our nearest star.

The sunspot, which scientists call Active Region 1402, appears as a huge blemish moving across the northern region of the sun in photos snapped by NASA's Solar Dynamics Observatory and other spacecraft. In addition to firing off several flares in recent days, the sunspot unleashed a powerful eruption late Sunday night (Jan. 22) to create the strongest solar radiation storm since 2005 to hit Earth.

That radiation storm is bombarding Earth today and may spark dazzling northern lights displays for skywatchers at northern latitudes where it is currently night, NASA scientists have said. It may also create minor interference with satellites in Earth orbit, but poses no threat to the six astronauts currently living on the International Space Station, they added.

Sunspots on the solar surface arise from intense magnetic activity on the sun. This activity can block the flow of heat through the sun's convection process, which in turn causes some areas of the star's surface to cool down. These cooler regions appear dimmer than their surrounding areas, creating the dark blemishes known as sunspots. Sunspots are temporary features on the sun that can last for several days or up to several weeks. They typically range from 1,500 miles to 30,000 miles (2,500-50,000 kilometers) in size.

One of the largest sunspots in recent years occurred in late 2011, when a sunspot about 50,000 miles (80,000 km) long, and 25,000 miles (40,000 km) wide was spotted by space telescopes.

The sun's sunspot cycle lasts 11 years and serves as a key identifier for the solar weather cycle. Right now, the sun is in an active phase of its current weather cycle — called Solar Cycle 24 — which is expected to peak in 2013.

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