Why you can’t see the Moon during a total solar eclipse (Synopsis) [Starts With A Bang]


“Even though the reason for taking the photographs was science, the result shows the enormous beauty of nature.” -Miloslav Druckmuller, eclipse photographer

During those moments of totality, the Sun is eclipsed by a new Moon, with the latter’s shadow falling onto Earth. From within that shadow, the Sun’s disk is blocked entirely, revealing a slew of fainter objects: stars, planets, and the Sun’s corona, all of which cannot normally be seen during the day. Yet one object even brighter than all the stars — the new Moon — will remain invisible throughout the eclipse.

The Sun’s atmosphere is not confined to the photosphere or even the corona, but rather extends out for millions of miles in space, even under non-flare or ejection conditions. Thanks to the masking technology of the coronagraph, we can view it from either Earth or space. Image credit: NASA’s Solar Terrestrial Relations Observatory.

Despite the Moon acting as the ultimate coronagraph, blocking out 100% of the Sun’s light, and despite the full Earth reflecting its light back onto the Moon, you won’t be able to see the lunar surface at all. Why is that? It’s the relative brightness of something very close by: the solar corona. Even though the Sun’s corona is some 400,000 times less bright than the Sun, it’s still ~10,000 times brighter than the new Moon, enough to render it totally invisible to human eyes. It’s like trying to see a firefly an inch away from a shining light bulb, when you’re standing 20 feet away.

Fireflies may give off light and put on a spectacular show, but at only 0.025 lumens apiece, they need to be far away from any other, much brighter light source to be seen. Image credit: Otto Phokus / flickr.

In short: the corona is too close and too bright, and that’s why the Moon is only visible in photographs.



from ScienceBlogs http://ift.tt/2wPIKTP

“Even though the reason for taking the photographs was science, the result shows the enormous beauty of nature.” -Miloslav Druckmuller, eclipse photographer

During those moments of totality, the Sun is eclipsed by a new Moon, with the latter’s shadow falling onto Earth. From within that shadow, the Sun’s disk is blocked entirely, revealing a slew of fainter objects: stars, planets, and the Sun’s corona, all of which cannot normally be seen during the day. Yet one object even brighter than all the stars — the new Moon — will remain invisible throughout the eclipse.

The Sun’s atmosphere is not confined to the photosphere or even the corona, but rather extends out for millions of miles in space, even under non-flare or ejection conditions. Thanks to the masking technology of the coronagraph, we can view it from either Earth or space. Image credit: NASA’s Solar Terrestrial Relations Observatory.

Despite the Moon acting as the ultimate coronagraph, blocking out 100% of the Sun’s light, and despite the full Earth reflecting its light back onto the Moon, you won’t be able to see the lunar surface at all. Why is that? It’s the relative brightness of something very close by: the solar corona. Even though the Sun’s corona is some 400,000 times less bright than the Sun, it’s still ~10,000 times brighter than the new Moon, enough to render it totally invisible to human eyes. It’s like trying to see a firefly an inch away from a shining light bulb, when you’re standing 20 feet away.

Fireflies may give off light and put on a spectacular show, but at only 0.025 lumens apiece, they need to be far away from any other, much brighter light source to be seen. Image credit: Otto Phokus / flickr.

In short: the corona is too close and too bright, and that’s why the Moon is only visible in photographs.



from ScienceBlogs http://ift.tt/2wPIKTP

Aucun commentaire:

Enregistrer un commentaire