Posted on 02/07/2022 12:10:12 PM PST by Red Badger
This animation features actual satellite images of the far side of the moon, illuminated by the sun, as it crosses between the DSCOVR spacecraft’s Earth Polychromatic Imaging Camera (EPIC) and telescope, and the Earth – one million miles away. Credit: NASA/NOAA
Although it looks fake, this viral footage of the Moon orbiting Earth is actually real. It’s just not new, despite making the rounds again this week; it actually was captured over 6 years ago.
Back in 2015, a NASA camera aboard the Deep Space Climate Observatory (DSCOVR) captured this unique series of images displaying the ‘dark side’ of the moon. The ‘dark side’ of the moon is often used to refer to the hemisphere of the moon that is facing away from Earth. However, it is more properly called the ‘far side’ as it is exposed to an equal amount of sunlight as the side facing Earth. We can never view the ‘far side’ from Earth due to a phenomenon called tidal locking, which occurs when an astronomical body takes the same amount of time to complete a full rotation around its axis and fully orbit around its partner.
Although DSCOVR’s primary purpose is to monitor solar winds for the National Oceanic and Atmospheric Administration (NOAA), the satellite also houses NASA’s Earth Polychromatic Imaging Camera (EPIC) which captured these images. This four-megapixel CCD camera and telescope maintains a constant view of Earth as it orbits and takes 13-22 images every day.
In order to capture Earth’s ‘natural color’, NASA combines three different monochrome exposures taken 30 seconds apart. The final combined image has a slight green offset to the right of the moon and thin blue and red offsets to the left of it which is due to the Moon’s movement between each exposure.
If you wish to view more images taken by EPIC, NASA publishes daily color images of different views of the Earth as it rotates throughout the day.
You can see how dark the moon really is because that shot shows it in full sunlight. It is really a dark gray rather than a silvery white it looks like from Earth
Moon over My Hammy
The Earth-Moon distance is only a quarter of that distance in the animation.............
NASAflix is my favorite entertainment company…
I wondered how they’d ever follow up on their hit Tang!
Hard to make out the huge chicom missle complex on the dark side...
Although they probably have given the klintoons many photos as thanks for the assist...
I see a hurricane to the west of Mexico.
Is the secret base visible? /s
Come on, look at the animation. The moon is moving at the earth’s rotational velocity. That means the moon will orbit the earth in 24 hours. That’s called a geostationary orbit, aka a geosynchronous equatorial orbit (GEO). A GEO is a circular orbit 22,236 miles in altitude above Earth’s Equator.
The Earth also rotates from west to east; anticlockwise if viewed from above the Earthly north pole. If you were viewing from above the solar north pole the Earth and moon also travel anticlockwise around the sun.
Neptune's moon, Triton, has a retrograde orbit opposite the planet's rotation around it's axis.
Very cool, and it’s getting the dark side too!
It is reflecting direct sun light.
Shouldn't it be at least as bright as the Earth?
Lol.
A little simple trigonometry will show that. Imagine the earth (8000 miles wide) is the base of an isoceles triangle whose height is the distance from earth to the satellite (872600 miles). Then the angle that the earth subtends from the satellite's POV is 2 * arctan(4000 / 872600) or 0.5253 degrees. That's right, the earth in the picture takes up barely 1/2 of a degree of the satellite's field of view.
Do the same thing with the moon's orbit. The moon's average distance from earth is 238,600 miles. 2 * arctan(238600 / 872600) is 30.6 degrees. So the earth (which is a little smaller than the frame size) would be 0.525 degrees of the satellite's field of view, while the moon's orbit end-to-end would be 30.6 degrees.
So while a point on the earth is moving (about) 0.525 degrees across the satellite's field of view, and the moon is moving only a little more than that, you're telling me that they're moving at the same rotational velocity? How is that remotely possible, since that point on the earth is rotating about 180 degrees in about 1/2 degree of apparent motion, and the moon is moving just a bit more than that, say 1 degree of apparent motion, but for the moon to rotate 180 degrees around the earth, it would need to move more than 30 degrees of apparent motion?
A gay black man once asked if I’d like to see that.
Sorry, I have a morbid sense of humor.
I think you’re assuming (subconsciously), because the image is flat and 2-D, that the moon is fairly close to the earth’s surface compared to the distance of the satellite. But it’s not: the distance from the satellite to the moon, when the moon is directly between the satellite and the earth, is less than 3/4ths the distance from the satellite to the earth.
The moon reflects about 10% of the sunlight that hits it so it is dark gray. Earth reflects about 30% on average.
Thanks for the helpful data.
On the other hand, a full moon at night is clearly not dark gray, and a moon visible during day light hours definitely has some visible white light.
So ... if I was standing on the earth side of the moon, looking
at the earth, wouldn’t it fill the sky ? Just looks odd to me.
Yes, it must have been summertime...............
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