The next major gas is nitrogen N2 at 3. Traces of sulfur dioxide, carbon monoxide, argon, and neon make up 0. Venus, like all planets, started out with an atmosphere containing hydrogen and helium. Carbon dioxide made up an ever-larger proportion of the atmosphere, leading to a sharp increase in the greenhouse effect. There are two main ways in which we study the atmosphere of Venus: space probes and earth-based observatories.
Space probes sent explicitly to Venus like Pioneer Venus orbit the planet and sometimes attempt a landing to. All the while they send crucial information data to Earth. Other missions, like Venera 2, are designed to plunge through the atmosphere and send back data to Earth before they perish due to atmospheric pressures.
On the ground, here on Earth, are missions that send radar signals to Venus and study the planet based on the received echoes. Since different elements react differently to light, this method is used to learn the atmospheric elements and their quantity. Venus is a hot, dry planet. Different layers of clouds move at varying speeds. Wind speeds in the upper layers reach mph kph. Persistent, dark streaks appear.
Scientists are so far unable to explain why these streaks remain stubbornly intact, even amid hurricane-force winds. They also have the odd habit of absorbing ultraviolet radiation. The most likely explanations focus on fine particles, ice crystals, or even a chemical compound called iron chloride. Although it's much less likely, another possibility considered by scientists who study astrobiology is that these streaks could be made up of microbial life, Venus-style.
These handy chemical cloaks would also absorb potentially damaging ultraviolet light and re-radiate it as visible light. There is much, it would seem, that she can teach us.
Our nearness to Venus is a matter of perspective. The planet is nearly as big around as Earth — 7, miles 12, kilometers across, versus 7, miles 12, kilometers for Earth.
From Earth, Venus is the brightest object in the night sky after our own Moon. The ancients, therefore, gave it great importance in their cultures, even thinking it was two objects: a morning star and an evening star. At its nearest to Earth, Venus is some 38 million miles about 61 million kilometers distant.
One more trick of perspective: how Venus looks through binoculars or a telescope. The complete cycle, however, new to full, takes days, while our Moon takes just a month. And it was this perspective, the phases of Venus first observed by Galileo through his telescope, that provided the key scientific proof for the Copernican heliocentric nature of the Solar System. Spending a day on Venus would be quite a disorienting experience — that is, if your ship or suit could protect you from temperatures in the range of degrees Fahrenheit Celsius.
For another, because of the planet's extremely slow rotation, sunrise to sunset would take Earth days. And by the way, the Sun would rise in the west and set in the east, because Venus spins backward compared to Earth. In winter, the tilt means the rays are less direct. No such luck on Venus: Its very slight tilt is only three degrees, which is too little to produce noticeable seasons. A critical question for scientists who search for life among the stars: How do habitable planets get their start?
The close similarities of early Venus and Earth, and their very different fates, provide a kind of test case for scientists who study planet formation. Similar size, similar interior structure, both harboring oceans in their younger days.
Yet one is now an inferno, while the other is the only known world — so far — to play host to abundant life. The factors that set these planets on almost opposite paths began, most likely, in the swirling disk of gas and dust from which they were born. Somehow, 4. Several might well have moved in closer, or farther out, as the solar system formed. If we could slice Venus and Earth in half, pole to pole, and place them side by side, they would look remarkably similar.
Each planet has an iron core enveloped by a hot-rock mantle; the thinnest of skins forms a rocky, exterior crust. On both planets, this thin skin changes form and sometimes erupts into volcanoes in response to the ebb and flow of heat and pressure deep beneath. Other possible similarities will require further investigation — and perhaps another visit to a planet that has hosted many Earth probes, both in orbit and briefly on the surface.
Subduction is believed to be the first step in creating plate tectonics. Magellan saw a land of extreme volcanism. The orbiter saw a relatively young surface, one recently reshaped in geologic terms , and chains of towering mountains. The maps show thousands of volcanoes and impact craters. There are two main upland areas, with a mountain range taller than Mt.
Dozens of spacecraft have visited Venus, but many mysteries remain. Most of its instruments have been studying the dense atmosphere and rapidly moving clouds, or investigating how the Sun affects the planet.
Venus Venus in ultraviolet light Access the image. Privacy Notice and Consent.
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