Foto - Toulouse - "Esgotar tempo até compreender que se vai sempre aprendendo" - 04-05-2015

"Esgotar tempo até compreender que se vai aprendendo"

Toulouse, 04-05-2015

JoanMira

Astronomy picture of the day - 2015 May 5 - Gravitational Anomalies of Mercury

Gravitational Anomalies of Mercury 
Image Credit: NASA, GSFC's SVS, JHU's APL, Carnegie Inst. Washington

Explanation: What's that under the surface of Mercury? The robotic MESSENGER spacecraft that had been orbiting planet Mercury for the past four years had been transmitting its data back to Earth with radio waves of very precise energy. The planet's gravity, however, slightly changed this energy when measured on Earth, which enabled the reconstruction of a gravity map of unprecedented precision. Here gravitational anomalies are shown in false-color, superposed on an image of the planet's cratered surface. Red hues indicate areas of slightly higher gravity, which in turn indicates areas that must have unusually dense matter under the surface. The central area is Caloris Basin, a huge impact feature measuring about 1,500 kilometers across. Last week, after completing its mission and running low on fuel, MESSENGER was purposely crashed onto Mercury's surface.

Foto - "Geometria e mais nada" - 04-05-2015

"Geometria e mais nada"

Toulouse, 04-05-2015

JoanMira

Astronomy picture of the day - 2015 May 4 - An Unexpected Aurora over Norway

An Unexpected Aurora over Norway 
Image Credit & Copyright: Tommy Richardsen

Explanation: Sometimes the sky lights up unexpectedly. A trip to northern Norway to photograph auroras was not going as well as hoped. It was now past midnight in Steinsvik, Troms, in northern Norway, and the date was 2014 February 8. Despite recent activity on the Sun, the skies were disappointing. Therefore, the astrophotographer began packing up to go. His brother began searching for a missing lens cap. When the sky suddenly exploded withspectacular aurora. Reacting quickly, a sequence detailing dramatic green curtains was captured, with the bright Moon near the image center, and the lens-cap seeking brother on the far right. The auroral flare lasted only a few minutes, but the memory of this event, the photographer speculates, will last much longer.