Eclipse week 3: A different perspectivePosted: July 22, 2009
As stunning as an eclipse is to see from the Earth it’s not the only vantage point we have on the event. Having sent probes in to space now for a number of years we can look back on the Earth to witness this event from the outside in. During the last major eclipse astronauts on board the ISS turned their cameras back to the earth and recorded these frankly terrifying images:
You can clearly see the ominous shadow that the Moon is casting on the Earth. In the center of that dark spot many onlookers are experiencing a total eclipse while around the periphery where the shadow is not so deep will be a partial eclipse. This shadow slowly makes its way across the face of the Earth. It’s a stunning and largely foreign perspective on an already amazing event.
As Emma discussed last post we are pretty much just lucky that the Sun and Moon appear to be the same size in the sky but one place in the Solar system in which this is obviously not the case is our own Moon. On the Moon the Earth appears in the sky much as the Moon does in ours and can on occasion eclipse the sun as well. Solar eclipses on the Moon though are a little different form here on Earth, for a start the Earth moves across the sky much slower on the Moon: a lunar day is about as long as our month meaning the Earth moves across the sky roughly 29 times slower than the Moon moves in our skies. The Earth also appears much larger in the sky both of which mean that Eclipses on the Moon last much longer than ours.
We don’t just have to imagine what an eclipse on the moon would like: there have been two Solar eclipses observed from the Moon over the years, one by human eyes and one by robotic. The first was witnessed by the Apollo 12 crew on their way home from the moon and snapped this image:
The small slither of light still visible is filtering through the Earth’s atmosphere, where if you just squint you might be able to make out some details of clouds. This is something we are generally unaccustomed to seeing in an eclipse as the Moon has no atmosphere.
The second eclipse in which the shadow is cast by us was recorded in wonderful HD by the Japanese Kaguya probe which is currently orbiting the Moon. To check out the full HD video of the eclipse you can here.
It’s hopeful to think that with our return to the Moon that such sights might become much more common.
Join us tomorrow when Niall will be talking about what eclipses have meant to people down through the years.