“The High Resolution Imaging Science Experiment (HiRISE) camera would
make a great backyard telescope for viewing Mars, and we can also use
it at Mars to view other planets. This is an image of Earth and the
moon, acquired on October 3, 2007, by the HiRISE camera on NASA’s Mars
Reconnaissance Orbiter.

At the time the image was taken, Earth
was 142 million kilometers (88 million miles) from Mars, giving the
HiRISE image a scale of 142 kilometers (88 miles) per pixel, an Earth
diameter of about 90 pixels and a moon diameter of 24 pixels. The phase
angle is 98 degrees, which means that less than half of the disk of the
Earth and the disk of the moon have direct illumination. We could image
Earth and moon at full disk illumination only when they are on the
opposite side of the sun from Mars, but then the range would be much
greater and the image would show less detail.

. . .

the Earth image we can make out the west coast outline of South America
at lower right, although the clouds are the dominant features. These
clouds are so bright, compared with the moon, that they are saturated
in the HiRISE images. In fact the red-filter image was almost
completely saturated, the Blue-Green image had significant saturation,
and the brightest clouds were saturated in the infrared image. This
color image required a fair amount of processing to make a nice-looking
release. The moon image is unsaturated but brightened relative to Earth
for this composite. The lunar images are useful for calibration of the

It may not look like much, but on that one tiny
blue and green orb exists all six billion or so of us – and has
existed, as far as we know, every human being ever
made/created/evolved/whatevered. Everything that we know, and
everything that we ever have known is contained on that little sphere.

even more amazing is that twelve people from that little blue-green orb
in the bottom left have actually managed to travel through space and
walk on the surface of the moon, all the way on the other side of the
picture. If that isn’t amazing, then I don’t know what is.

Image, caption, and full-size photo from