On October 22 and 25, 1975, the two probes Venus 9 and Venus 10 softly landed 2 000 kilometers apart, obtaining the first images of the surface of Venus. The photographic result is not exceptional: the two black and white pictures have poor definition, but they do have great scientific interest. First of all, the area in the picture taken appears to be curved, as was expected, because the density of the atmosphere distorts the view of objects when seen at a certain distance. Light on Venus is deflected in such a way that an observer on the surface would see the ground "rise up" around him so that he would get the feeling of being in an enormous bowl. In both locations filmed by the probes, the ground appears to be covered with rocks and stones. From the pictures, the stones seem to be rather flat and have very sharp corners, which leads to the assumption that they were detached from the "mother" rock a relatively short time ago, or that they were constantly subjected to erosion. Their surface is bright, shining like the steel ring attached to the probe which appears in the lower margins of the two photographs. We can deduce that the stones are relatively "clean", that they are not covered with dust or smaller objects. On the other hand, the surface between the stones is dark, and does not reflect much light. This may be due to the presence of dust or smaller objects, or enhanced roughness. Overall, the Earth landscape that is most similar to the environment on Venus is the rock desert, where the change in temperature is the main factor in eroding the rocks: the hot days and cold nights make them expand and contract, and thus they break quite easily. However, the temperature on Venus never goes down: how we can explain the rocky ground? There may be many answers which are not all accepted by scientists. The first hypothesis refers to the continuous bombardment by meteorites: the falling of various sized bodies would have broken the surface of the planet, throwing the fragments around the area of impact. Instead, another hypothesis considers the action of the wind. In fact, even if the wind measured at the landing site seems to be much weaker with respect to Earth standards, we must always keep in mind that the measurements were taken in an atmosphere that is ten times denser than that of our planet: a simple breeze on Venus would be comparable to the raging wind along the coast during a strong sea-storm. Finally, we must also consider the possibility that the corrosive substances in the clouds may, in some way, reach the surface, combining its disintegrating effect with the heat. To know more, we had to wait seven years, when in March of 1982, two other Soviet probes, Venus 13 and Venus 14, sent to Earth the first two color photographs of the surface of Venus. The landscape is completely similar to that observed in the previous images, but finally, it shows the true picture: a panorama full of rust-colored rocks with a portion of the yellow sky of Venus at the edges. However, the probes were equipped with something more: a drilling arm that penetrated a few centimeters into the ground and removed a sample to be analyzed in the small automatic on-board laboratory. The results were surprising: the rocks are composed of basalt, similar to those that are generated on Earth by the great active ridges at the bottom of the oceans. Perhaps the heart of Venus is more similar to our planet than what we thought and its surface has also been shaped by the same phenomena.
On October 22 and 25, 1975, the two probes Venus 9 and Venus 10 softly landed 2 000 kilometers apart, obtaining the first images of the surface of Venus. The photographic result is not exceptional: the two black and white pictures have poor definition, but they do have great scientific interest. First of all, the area in the picture taken appears to be curved, as was expected, because the density of the atmosphere distorts the view of objects when seen at a certain distance. Light on Venus is deflected in such a way that an observer on the surface would see the ground "rise up" around him so that he would get the feeling of being in an enormous bowl. In both locations filmed by the probes, the ground appears to be covered with rocks and stones. From the pictures, the stones seem to be rather flat and have very sharp corners, which leads to the assumption that they were detached from the "mother" rock a relatively short time ago, or that they were constantly subjected to erosion. Their surface is bright, shining like the steel ring attached to the probe which appears in the lower margins of the two photographs. We can deduce that the stones are relatively "clean", that they are not covered with dust or smaller objects. On the other hand, the surface between the stones is dark, and does not reflect much light. This may be due to the presence of dust or smaller objects, or enhanced roughness. Overall, the Earth landscape that is most similar to the environment on Venus is the rock desert, where the change in temperature is the main factor in eroding the rocks: the hot days and cold nights make them expand and contract, and thus they break quite easily. However, the temperature on Venus never goes down: how we can explain the rocky ground? There may be many answers which are not all accepted by scientists. The first hypothesis refers to the continuous bombardment by meteorites: the falling of various sized bodies would have broken the surface of the planet, throwing the fragments around the area of impact. Instead, another hypothesis considers the action of the wind. In fact, even if the wind measured at the landing site seems to be much weaker with respect to Earth standards, we must always keep in mind that the measurements were taken in an atmosphere that is ten times denser than that of our planet: a simple breeze on Venus would be comparable to the raging wind along the coast during a strong sea-storm. Finally, we must also consider the possibility that the corrosive substances in the clouds may, in some way, reach the surface, combining its disintegrating effect with the heat. To know more, we had to wait seven years, when in March of 1982, two other Soviet probes, Venus 13 and Venus 14, sent to Earth the first two color photographs of the surface of Venus. The landscape is completely similar to that observed in the previous images, but finally, it shows the true picture: a panorama full of rust-colored rocks with a portion of the yellow sky of Venus at the edges. However, the probes were equipped with something more: a drilling arm that penetrated a few centimeters into the ground and removed a sample to be analyzed in the small automatic on-board laboratory. The results were surprising: the rocks are composed of basalt, similar to those that are generated on Earth by the great active ridges at the bottom of the oceans. Perhaps the heart of Venus is more similar to our planet than what we thought and its surface has also been shaped by the same phenomena.
