Venus, sometimes referred to as Earth’s “evil twin,” is a hellish place. It’s the hottest world in our solar system, boasting temperatures of close to 480oC (900oF), hot enough to melt lead. This scorching heat has resulted in a parched surface that's devoid of liquid water, making it an extremely unlikely planet to host life. It is also enveloped in a dense, toxic atmosphere made up of a choking mix of carbon dioxide and clouds of sulfuric acid. This thick cloak means that Venus does not give up its surface features to ground-based optical telescopes, which only give us a rather milky portrait of the planet.
In order to peep underneath this veil, scientists in the past have enlisted the help of probes such as NASA’s Magellan spacecraft, which uses a sophisticated imaging radar to make highly detailed maps of the planet’s surface. But it turns out we needn’t travel 25 million miles to see what lies beneath its thick atmosphere. By combining two earthbound observatories, scientists have managed to produce a different but incredibly detailed view of the planet.
The new image, pictured above, shows us striking features like mountains, craters and ridges. The black line running through the middle highlights a region where it is difficult to obtain well-resolved data using this technique. To produce the image, radar signals emitted from the National Science Foundation’s Arecibo Observatory made their way first through Earth’s atmosphere and then penetrated Venus’ before bouncing off its surface and returning to Earth, ready to be picked up by the Green Bank Telescope’s powerful receivers. This technique is known as bistatic radar.
Scientists first started making these ground-based radar observations of Venus back in 1988, with the most recent data collected in 2012. By comparing different images taken over time, which should reveal any changes in surface features occurring, they can spot things like active volcanism or maybe even geologic processes that could provide us with hints about the planet’s subsurface conditions.
“It is painstaking to compare radar images to search for evidence of change, but the work is ongoing,” Bruce Campbell, senior scientist with the Center for Earth and Planetary Studies said in a statement. “In the meantime, combining images from this and an earlier observing period is yielding a wealth of insight about other processes that alter the surface of Venus.” You can read about these comparisons in the journal Icarus.