Just Passing By

On 10 April, the ESA BepiColumbo spacecraft flew by Earth during a gravity assist maneouver on its way to Mercury. This 360-degree VR simulation of the flyby  takes you on a trip past Earth at the distance of only 12,700 km. The simulation displays the fields of view a pair of BepiColombo’s science instruments (MERTIS and PHEBUS) and two of its three MCAM selfie cameras.

Video Credit: ESA


earthterminator_iss002_920This picture was taken from the International Space Station orbiting at an altitude of 390 km. The terminator is the line between day and night. In pictures of  airless moons it’s a firm line, but no such sharp boundary marks the division between day and night in this picture of ocean and clouds on Earth. Instead, the shadow line is diffuse and shows the gradual transition to darkness as twilight falls. The Sun illuminates the scene from the right, and the cloud tops reflect gently reddened sunlight filtered through the troposphere, the lowest layer of the atmosphere. The upper atmosphere scatters blue sunlight and fades into the blackness of space.

Image Credit: NASA

That Pale Blue Dot

This is an updated version of the Pale Blue Dot image taken by the Voyager 1 spacecraft 30 years ago today. It was created using modern image-processing software and techniques while trying to remain faithful to the original. Like the original, this new color view shows the Earth as a single blue pixel in the vastness of space. Rays of sunlight scattered within the camera optics stretch across the scene, one of which intersects with Earth. Look closely at the stripe just right of center. That speck a bit past half way up isn’t dust on your screen. It’s the Earth.

The image was taken just before Voyager 1’s cameras were turned off to conserve power because the probe would not make another planetary flyby. Shutting down instruments and other systems on the two Voyager spacecraft has been a gradual and ongoing process that has helped keep them running as they have left the Solar System.

Image Credit: NASA


This video takes us around the Moon and shows how it is illuminated not only by the brilliant light of the Sun but also by light reflected from the Earth. The trip starts on the side facing away from Earth where part of the surface is brightly illuminated by the Sun but the rest is totally dark. Moving around the Moon, the Earth rises, and its reflected bluish light illuminates the Moon’s surface. This dull glow is the earthshine. (You can clearly see it from Earth when the Moon appears as a crescent in the evening or morning sky.) When the Sun emerges from behind the Moon, the brilliant crescent is seen, but the earthshine is still faintly visible.

Video Credit: ESO

Spring Has Sprung …

… here in the Northern Hemisphere. The equinox occurred last week. At an equinox Earth’s terminator, the dividing line between day and night, runs through the planet’s north and south poles as seen at the start of this time-lapse video which crams an entire year into twelve seconds. It was put together using Meteosat infrared images taken every day at the same local time from a geosynchronous orbit. The video actually starts at the September 2010 equinox. As the Earth revolves around the Sun, the terminator tilts as less daily sunlight falls on the northern hemisphere, reaching the solstice and northern hemisphere winter at the maximum tilt. As the year continues, the terminator tilts back again to the March 2011 equinox halfway through the video. Then the terminator swings past the poles, until the June 2011 solstice, the start of northern summer. The video ends as the September equinox returns.

Video Credit: NASA / Meteosat / Robert Simmon