Looking Back At Earth From Mars Gives Us Pause

What were you doing on Nov. 20, 2016? That’s when NASA’s Mars Reconnaissance Orbiter (MRO) snapped this montage of Earth and the moon from 127 million miles (205 million km) away. Click for hi res image. Credit: NASA/JPL-Caltech/Univ. of Arizona

After you’ve traveled a long way, whether in life or miles, it’s nice to look back. You can see the world with fresh eyes. That’s why I like these now-and-again photos of our home from space. They place the Earth in the context of the greater solar system, the way we see Mars or Jupiter or Venus through our little telescopes from our front yards.

This composite image of Earth and its moon, as seen from Mars, combines the best Earth image with the best moon image from four sets of images acquired on Nov. 20, 2016, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. Because Earth is so much brighter than the moon, the photos of each were processed separately before combining them into one image otherwise the moon would barely be visible next to the planet.  The montage keeps the correct sizes and positions of the two bodies relative to each other.

This earlier photo of Earth and moon was also made with the MRO HiRISE camera on Oct. 3, 2007. Credit: NASA/JPL-Caltech/Univ. of Arizona

Click on the image for a larger file to better pick out Australia, the reddish feature in the middle of the planet, the bright blob of Antarctica at bottom and several patches of white, reflective clouds.  You can also spot the familiar trio of bright, rayed craters Copernicus, Kepler and Aristarchus a little bit above center in the moon photo. They’re blended together but still obvious as mottled patch set off against the dark lava plain called Oceanus Procellarum, the Ocean of Storms. Mars was 127 million miles away at the time the pictures were taken.

On March 7, 1947, not long after the end of World War II and years before Sputnik ushered in the space age, a group of soldiers and scientists in the New Mexico desert saw something new and wonderful in these grainy black-and-white-photos – the first pictures of Earth as seen from altitude greater than 100 miles in space. Credit: Johns Hopkins Applied Physics Laboratory

It was only 70 years ago this March that we first began to appreciate our small-globe existence. That’s when John T. Mengel began experimenting with captured German V-2 rockets in the New Mexico desert. Mengel launched the rockets more than 100 miles into space to learn more about the upper atmosphere. He re-designed the nose shell, replacing the V-2 warhead with cameras and scientific instruments in a modern example of beating swords into plowshares. Before the V-2 launches, the highest humankind had nudged into outer space was just 13.7 miles in the Explorer II balloon in 1935.

Since then, we’ve been to Pluto and beyond. The most distant manmade spacecraft, Voyager 1, is currently 12.8 billion miles (20.6 billion km) from Earth. A radio signal sent traveling at the speed of light would take over 19 hours to reach the probe. Launched in 1977, the Voyager 1 made close flybys of Jupiter and Saturn and sent back incredibly detailed closeups of their clouds, moons and rings. You can watch it and its sister spacecraft, Voyager 2, recede in real time at this website.