Thursday, July 1, 2010

Venus Express

Venus Express in Orbit

Venus on the Half Shell

Venus With Clouds

And Without Clouds

Astronaut on the Surface

"Fly me to the moon, Let me sing among those stars, Let me see what spring is like on Jupiter and Mars... In other words, hold my hand... In other words, baby kiss me."

Venus was the Roman goddess of love and beauty (Greek: Aphrodite; Babylonian: Ishtar (which actually wasn't that bad a movie)), and her name was given to the planet that was closest to us, the second from the Sun, maybe because it was so bright and shiny and cute. Ancient people thought it might actually be two planets, because it was so easy to see in the early evenings, and the early mornings, which is why it was sometimes called both The Evening Star, and The Morning Star. I don't know why they called it that because it wasn't a star at all... and still isn't, although it is the brightest natural object in the sky (besides the Sun and the Moon).
Venus is also often referred to as the Earth's sister planet (and Jupiter is our big brother), because both planets are very similar in size (Venus is just 404 miles smaller than the Earth at the equator, and has 81.5% of the mass), density, and volume. And both have relatively young surfaces, about 100 million years for the Earth, and 500 million for Venus.
Other than that though Venus is very, very, different than the Earth. Very different. In many respects this beautiful jewel of the sky is the physical embodiment of the Abrahamic version of Hell (that's why so many souls of passed Republicans can be found there).
Venus is the second planet from the Sun (Mercury being the closest, and the Earth the third), which means it receives much more solar energy than we do here on Earth. It is anywhere from 66,000,000 to 67,500,00 miles from it (it's orbit is elliptical, like all of the planets, but the closest to being circular than any other. The Earth's orbit is more elliptical, hence its distance from the Sun varies more, from 91,300,000 to 94,400,000 million miles). And the distance between the Earth and Venus varies to large degrees depending on where they are in their respective orbits. 23,700,000 million miles at is closest, to 162,000,000 when Venus is furthest away, when it is hiding behind the Sun. In comparison Earth can be anywhere from 36,000,000 to 250,000,000 million miles apart from Mars, the fourth planet from the Sun. The point being here that Venus gets hotter because it is closer to the Sun, which also means its year is shorter than ours because the distance to circle the sun is less. Venus's year is 224.65 Earth days long.
Its day is much longer though. I don't know why. Nobody does, that's just the way it is and we must learn to accept it. A day on Venus is 243 Earth days long, which means two things; Its day is longer than its freaking year, and a 243 day long day makes for a tiresome work week.
Also, Venus revolves around its axis in a retrograde fashion. In other words it spins clockwise, when the rest of the planets (except Uranus) spin counter-clockwise, making the Sun rise in the west, and set in the east.
Now the Hell thing. Venus is very hot at its surface, and not just because it is closer to the Sun. Something happened a few billion years ago when it was thought to have similar surface conditions as the Earth, with liquid water. But what is called a Runaway Greenhouse Effect evaporated all of the water, the atmosphere became more dense. The water dissociated, meaning the sunlight, or solar wind broke up the water into its oxygen and hydrogen atoms. The hydrogen atoms, being very light (and there is hardly any magnetic fields protecting Venus, and holding hydrogen in), were lost forever to space, so almost all of the planet's water was gone. That sucked for Venus.
The greenhouse effect continued, and today Venus has 93 times more atmosphere than we do on Earth. That's our entire atmosphere, which gives us enough trouble as it is, times 93. The surface pressure on Venus is about 92 times what it is here. 92 times! Walking around on Venus would be like walking around under the ocean a little more than half a mile down. 0.621371 miles to be exact. It's crushing.
And what is that atmosphere made of? Funny you should ask, dear readers. It's certainly not made of good old air like we have on Earth. Oh no, it's made almost entirely of carbon dioxide, the stuff we breath out, not in. There are no plants on Venus, or oceans, so all of that carbon stays in the atmosphere rather than being able to be absorbed by rocks, biomass, and water.
Above all that carbon dioxide are clouds of mostly sulfur dioxide and sulfuric acid droplets. Yeah, that means it can rain freaking acid (it does here on Earth as well, but due to air pollution caused by humans)! These clouds reflect about 60% of the sunlight that falls on them back into space, and prevents the direct observation of Venus's surface in the visible spectrum of light (picture above with all of the clouds). We didn't know what was down there, on the surface of Venus, until a short while ago.
With that dense of an atmosphere Venus retains a great deal of the Sun's radiation via that greenhouse effect. As a matter of fact at the surface the temperature is about 860% Fahrenheit, hot enough to melt lead. Venus is even hotter than Mercury, which is much closer to the sun, all because of that greenhouse effect.
So if you were to be standing on the surface of Venus somehow we would be hard pressed (excuse the pun) to see which would kill you first... the lack of oxygen, the atmospheric pressure, or the great amount of heat (it's a good thing I have my thermal, ectoskeleton, scuba tanked spacesuit on (pictured above))
That greenhouse effect is one good reason to study Venus, to make sure something like that doesn't happen here (it won't, but many bad things can, and will happen if we don't take care), so we've sent many spaceships there to see what was going on.
The very first space probe to another planet (the moon not being a planet) was Venera 1, sent by the Ruskies, or back then, the Soviet Ruskies. It was supposed to crash into Venus back in 1961 but it missed. Our own first attempt the next year, Mariner 1, ended badly as well, being self destructed moments after launch due to a fault in the guidance system. Mariner 2 was much more successful, and flew by Venus on December 14, 1962, becoming the first interplanetary mission that worked. That was when Dr. Carl Sagan's theory of a hot Venus was confirmed, ending hopes that conventional forms of life might be plentiful on the planets surface.
The Soviet's Venera 7 probe became the first spacecraft to land on another planet in 1970. It returned a weak signal supplying temperature data for 23 minutes, the first telemetry received from the surface of another planet.
Radar mapping of Venus was carried out by both the United States and the Soviet Union throughout the 1980's. The U.S. with its Pioneer Venus Orbiter and Magellan probe, and Russia with Venera 15 and 16.
And in 2005 those wily Europeans at the European Space Agency (ESA) sent the Venus Express, which established a polar orbit around the planet in April of 2006. It's mission is to study the atmosphere until it runs out of gas (the Venus Express, not the atmosphere) in December of next year. It is the craft that has found evidence of large amounts of water (probably atmospheric) on Venus in it's distant past. It has also confirmed the presence of lightning on Venus, and that it is more common there than it is here on Earth. It also discovered a huge double atmospheric vortex (a form of cyclone) exists at the south pole of the planet. Isn't that wonderful!?
The Venus Express is giving us vital information on the structure of the intricate Venusian atmosphere, sifting out more clues of how the runaway greenhouse effect came into being, which provides a better understanding of how our own atmosphere evolves, which is extremely important considering the activity of humans is interacting with it in ways that are most likely hazardous for our continued existence.
That is why space exploration is important. That is why we must continue funding it (Congressional budget considerations are always a major concern regarding continued space exploration), especially robotic missions that are far less costly and safer than maned missions, and provide just as much valuable information.
The answers to questions regarding man's (and woman's) survival are out there. We need to keep looking.
And that's all I've got to say about Venus right now (Forrest Gump).
Maybe more later... be patient.

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