Why is Venus Earth Gemini

Venus - devilish twin of the earth

Scientists want to learn more about the Earth-like second planet in order to better understand the Earth's greenhouse effect

Scientists from the United States and the European Union recently met in Nice (France) for an astronomical conference focusing on "Venus". During the meeting, the participants urged all those responsible to actually carry out the ESA's "Venus Express" mission planned for 2005, especially since the new data should help to create climate models with which the intensity and consequences of the terrestrial greenhouse effect can be better understood understand and calculate.

Seen from our home star, Venus is the second planet in the solar system. Its almost circular orbit around the sun brings it - even if only for a short time - very close to the earth: up to 38.5 million kilometers (greatest distance: 260.9 million kilometers). No other planet is so close to its blue planetary companion.

Hell Planet

The data that the Soviet Veneranssdc.gsfc.nasa.gov/planetary/venera.html and American Mariner and Pioneer probes (and Magellan) collected from the (temporarily) closest planet does not exactly present a friendly neighbor. No, it must look like this in hell. On Venus it seems to be boiling, boiling and smoking all over the place and incessantly. Even with the best spaceman outfit, astronauts could not survive on this geologically very active planet. Here, where the pressure is around 90 times higher than on the earth's surface, temperatures of around 470 degrees Celsius (mean) prevail.

It is mainly due to the opaque, highly reflective atmosphere, which consists mainly of carbon dioxide (around 96%) and also of nitrogen and traces of water vapor, carbon monoxide, sulfur dioxide, sulfuric acid and some noble gases and which consists of several layers of dense, sulfur-containing It is thanks to the cloud cover and the landscape interspersed with huge plains, low plains, volcanic elevations and highlands that Venus is sometimes referred to as the "devilish twin" of the earth.

Although the internal structure of Venus is similar to that of Earth, although the parameters of size, mass and density are approximately the same, the thick carpet of clouds makes the difference. Wrapped in a layer consisting largely of carbon dioxide and sulfuric acid, which captures any radiation (and heat) but does not let it out, there is an enormous greenhouse effect on Venus all year round, which heats the planet more and more from year to year .

Learn from Venus

Nonetheless, Venus is an excellent study object with which the worldwide scenario of a global earthly greenhouse effect can be played out in a vivid way. Most scientists now believe that they can learn a lot about the early and late earth years from Venus - as did those researchers from the European Union and NASA who recently met in Nice to discuss possible missions to Venus in 2005 to discuss. "Venus and Earth went different ways," says planetary researcher Larry Esposito from the University of Colorado in Boulder.

But as a result of human activities, the earth is developing more and more in the same direction as Venus. As we understand the history of Venus better, we can better fine-tune our models for the Earth.

Most researchers have recently rethought. While it was initially controversially discussed whether global warming was due to emissions such as carbon dioxide, methane and other gases produced by humans, now hardly any scientist denies this connection. Nevertheless, the efforts of researchers to predict the global developments that lead to the greenhouse effect turned out to be contradictory and unreliable. "If we had the same heat and the same conditions on Earth as on Venus, the resulting greenhouse effect would destroy all life on Earth," states Andrew Ingersoll from the California Institute of Technology.

Something like this won't happen on Earth anytime soon, but Venus gives us an impressive picture of the effects of long-term climate change.

Landing on Venus

The researchers at least agree that the models that are supposed to allow predictions of the greenhouse effect must be optimized. And this is exactly where the Venus data could help, provided that the astronomers succeed in reconciling the previous and expected future information about Venus with current and future climate models. In the opinion of Dr. Esposito of a huge step forward: "We have to visit Venus in order to collect even more information about the atmospheric composition and that on its surface," said the planetary researcher. For this reason, Espositos believes that NASA should now think more about whether it should not also use a landing in parallel to the ESA "Venus Express" mission planned for 2005, which provides for a comprehensive exploration of the atmosphere and plasma environment of the planet Venus -Orbiters make sense. Landing with a probe on the "hot" surface of Venus, where even lead would melt, would be a huge challenge, but the yield would be even greater, according to the researcher.

With all of the above, the Venus Express probe could help clear up another important issue. Because actually, according to the researchers, it should be much hotter on Venus. But regardless of the facts that Venus is closer to the sun than the earth, that it revolves around the sun more slowly than our home planet, and that it has an almost impenetrable cloud cover, that it reflects no less than 75 percent of the incident solar radiation (at the earth it is just 30 percent), it is comparatively warm there in view of the currently known climate models. "The climate on Venus' surface does not completely match the extrapolated data as it would be on Earth," says planetary researcher Fred Taylor, who researches and teaches at the University of Oxford (England). "Something can be wrong with our models." (Harald fence)

Read comments (8 posts) https://heise.de/-3425165Report errorDrucken