Posted on by Fraser Cain

Earth Surface Temperature

Sea temperature model

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The average Earth surface temperature is 14° C. That’s 287 kelvin, or 57.2° F.

As you probably realize, that number is just an average. The Earth’s temperature can be much higher or lower than this temperature. In the hottest places of the planet, in the deserts near the equator, the temperature on Earth can get as high as 57.7° C. And then in the coldest place, at the south pole in Antarctica, the temperature can dip down to -89° C.

The reason the average temperature on Earth is so high is because of the atmosphere. This acts like a blanket, trapping infrared radiation close to the planet and warming it up. Without the atmosphere, the temperature on Earth would be more like the Moon, which rises to 116° C in the day, and then dips down to -173° C at night.

We’ve written several articles about the temperature of the planets. Here’s an article about the temperature of all the planets, and here’s an article about the temperature of the Moon.

If you’d like more information on the Earth, check out NASA’s Solar System Exploration Guide on Earth. And here’s a link to NASA’s Earth Observatory.

We’ve also recorded an entire episode of Astronomy Cast all about Earth. Listen here, Episode 51: Earth.

Posted on by Fraser Cain

Venus Length of Day

Venus captured by Magellan.

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The Venus length of day is 243 days.

But the story is a little stranger than that. Venus is actually rotating backwards compared to the rest of the planets in the Solar System. Seen from above the north pole, Venus is slowly rotating in a clockwise direction. Compare this to Earth and the rest of the planets, which rotate in a counter-clockwise direction.

And it gets even stranger, when you consider that a year on Venus only lasts 224.7 days. In other words, a day on Venus is actually longer than a year on Venus. If you could actually stand on the surface and see the Sun, you would see the Sun rise in the West, and pass through the sky over the course of 116.75 days and then set in the East. So a solar day on Venus is 116.75 days.

Astronomers aren’t sure why the length of day on Venus takes so long, and why Venus is rotating backwards. It’s possible that Venus was struck by a large object early on in its history, which flipped it over and caused its strange rotation.

We’ve written many articles about the day length of the planets, here’s an article about a day on Mars, and here’s an article about a day on Saturn.

If you’d like more info on Venus, check out Hubblesite’s News Releases about Venus, and here’s a link to NASA’s Solar System Exploration Guide on Venus.

We’ve also recorded an episode of Astronomy Cast all about Venus. Listen here, Episode 50: Venus.

Posted on by Fraser Cain

Planets Fact Sheet

Mercury
Mass: 0.3302 x 1024 kg
Volume: 6.083 x 1010 km3
Average radius: 2439.7 km
Average diameter: 4879.4 km
Mean density: 5.427 g/cm3
Escape velocity: 4.3 km/s
Surface gravity: 3.7 m/s2
Visual magnitude: -0.42
Natural satellites: 0
Rings? – No
Semimajor axis: 57,910,000 km
Orbit period: 87.969 days
Perihelion: 46,000,000 km
Aphelion: 69,820,000 km
Mean orbital velocity: 47.87 km/s
Maximum orbital velocity: 58.98 km/s
Minimum orbital velocity: 38.86 km/s
Orbit inclination: 7.00°
Orbit eccentricity: 0.2056
Sidereal rotation period: 1407.6 hours
Length of day: 4222.6 hours
Discovery: Known since prehistoric times
Minimum distance from Earth: 77,300,000 km
Maximum distance from Earth: 221,900,000 km
Maximum apparent diameter from Earth: 13 arc seconds
Minimum apparent diameter from Earth: 4.5 arc seconds
Maximum visual magnitude: -1.9

Venus
Mass: 4.8685 x 1024 kg
Volume: 92.843 x 1010 km3
Average radius: 6051.8 km
Average diameter: 12103.6 km
Mean density: 5.243 g/cm3
Escape velocity: 10.36 km/s
Surface gravity: 8.87 m/s2
Visual magnitude: -4.40
Natural satellites: 0
Rings? – No
Semimajor axis: 108,210,000 km
Orbit period: 224.701 days
Perihelion: 107,480,000 km
Aphelion: 108,940,000 km
Mean orbital velocity: 35.02 km/s
Maximum orbital velocity: 35.26 km/s
Minimum orbital velocity: 34.79 km/s
Orbit inclination: 3.39°
Orbit eccentricity: 0.0067
Sidereal rotation period: 5832.5 hours
Length of day: 2802.0 hours
Discovery: Known since prehistoric times
Minimum distance from Earth: 38,200,000 km
Maximum distance from Earth: 261,000,000 km
Maximum apparent diameter from Earth: 66.0 arc seconds
Minimum apparent diameter from Earth: 9.7 arc seconds
Maximum visual magnitude: -4.6

Earth
Mass: 5.9736 x 1024 kg
Volume: 108.321 x 1010 km3
Average radius: 6,371.0 km
Average diameter: 12,742 km
Mean density: 5.515 g/cm3
Escape velocity: 11.186 km/s
Surface gravity: 9.798 m/s2
Visual magnitude: -3.86
Natural satellites: 1
Rings? – No
Semimajor axis: 149,600,000 km
Orbit period: 365.256 days
Perihelion: 147,090,000 km
Aphelion: 152,100,000 km
Mean orbital velocity: 29.78 km/s
Maximum orbital velocity: 30.29 km/s
Minimum orbital velocity: 29.29 km/s
Orbit inclination: 0.00°
Orbit eccentricity: 0.0167
Sidereal rotation period: 23.9345 hours
Length of day: 24.0000 hours
Axial tilt: 23.45°

Mars
Mass: 0.64185 x 1024 kg
Volume: 16.318 x 1010 km3
Average radius: 3,389.5 km
Average diameter: 6,779 km
Mean density: 3.933 g/cm3
Escape velocity: 5.03 km/s
Surface gravity: 3.71 m/s2
Visual magnitude: -1.52
Natural satellites: 2
Rings? – No
Semimajor axis: 227,920,000 km
Orbit period: 686.980 days
Perihelion: 206,620,000 km
Aphelion: 249,230,000 km
Mean orbital velocity: 24.13 km/s
Orbit inclination: 1.850°
Orbit eccentricity: 0.0935
Sidereal rotation period: 24.6229 hours
Length of day: 24.6597 hours
Axial tilt: 25.19 °
Discovery: Known since prehistoric times
Minimum distance from Earth: 55,700,000 km
Maximum distance from Earth: 401,300,000 km
Maximum apparent diameter from Earth: 25.1 arc seconds
Minimum apparent diameter from Earth: 3.5 arc seconds
Maximum visual magnitude: -2.91

Jupiter
Mass: 1,898.6 x 1024 kg
Volume: 143,128 x 1010 km3
Average radius: 69,911 km
Average diameter: 139,822 km
Mean density: 1.326 g/cm3
Escape velocity: 59.5 km/s
Surface gravity: 24.79 m/s2
Natural satellites: 63
Rings? – Yes
Semimajor axis: 778,570,000 km
Orbit period: 4,332.589 days
Perihelion: 740,520,000 km
Aphelion: 816,620,000 km
Mean orbital velocity: 13.07 km/s
Orbit inclination: 1.304°
Orbit eccentricity: 0.0489
Sidereal rotation period: 9.9250 hours
Length of day: 9.9259 hours
Axial tilt: 3.13°
Discovery: Known since prehistoric times
Minimum distance from Earth: 588,500,000 km
Maximum distance from Earth: 968,100,000 km
Maximum apparent diameter from Earth: 50.1 arc seconds
Minimum apparent diameter from Earth: 29.8 arc seconds
Maximum visual magnitude: -2.94

Saturn
Mass: 568.46 x 1024 kg
Volume: 82,713 x 1010 km3
Average radius: 58,232 km
Average diameter: 116,464 km
Mean density: 0.687 g/cm3
Escape velocity: 35.5 km/s
Surface gravity: 10.44 m/s2
Natural satellites: 60
Rings? – Yes
Semimajor axis: 1,433,530,000 km
Orbit period: 10,759.22 days
Perihelion: 1,352,550,000 km
Aphelion: 1,514,500,000 km
Mean orbital velocity: 9.69 km/s
Orbit inclination: 2.485°
Orbit eccentricity: 0.0565
Sidereal rotation period: 10.656 hours
Length of day: 10.656 hours
Axial tilt: 26.73°
Discovery: Known since prehistoric times
Minimum distance from Earth: 1,195,500,000 km
Maximum distance from Earth: 1,658,500,000 km
Maximum apparent diameter from Earth: 20.1 arc seconds
Minimum apparent diameter from Earth: 14.5 arc seconds
Maximum visual magnitude: 0.43

Uranus
Mass: 86.832 x 1024 kg
Volume: 6,833 x 1010 km3
Average radius: 25,362 km
Average diameter: 50,724 km
Mean density: 1.270 g/cm3
Escape velocity: 21.3 km/s
Surface gravity: 8.87 m/s2
Natural satellites: 27
Rings? – Yes
Semimajor axis: 2,872,460,000 km
Orbit period: 30,685.4 days
Perihelion: 2,741,300,000 km
Aphelion: 3,003,620,000 km
Mean orbital velocity: 6.81 km/s
Orbit inclination: 0.772°
Orbit eccentricity: 0.0457
Sidereal rotation period: 17.24 hours
Length of day: 17.24 hours
Axial tilt: 97.77°
Discovery: 13 March 1781
Minimum distance from Earth: 2,581,900,000 km
Maximum distance from Earth: 3,157,300,000 km
Maximum apparent diameter from Earth: 4.1 arc seconds
Minimum apparent diameter from Earth: 3.3 arc seconds
Maximum visual magnitude: 5.32

Neptune
Mass: 102.43 x 1024 kg
Volume: 6,254 x 1010 km3
Average radius: 24,622 km
Average diameter: 49,244 km
Mean density: 1.638 g/cm3
Escape velocity: 23.5 km/s
Surface gravity: 11.15 m/s2
Natural satellites: 13
Rings? – Yes
Semimajor axis: 4,495,060,000 km
Orbit period: 60,189 days
Perihelion: 4,444,450,000 km
Aphelion: 4,545,670,000 km
Mean orbital velocity: 5.43 km/s
Orbit inclination: 1.769°
Orbit eccentricity: 0.0113
Sidereal rotation period: 16.11 hours
Length of day: 16.11 hours
Axial tilt: 28.32°
Discovery: 23 September 1846
Minimum distance from Earth: 4,305,900,000 km
Maximum distance from Earth: 4,687,300,000 km
Maximum apparent diameter from Earth: 2.4 arc seconds
Minimum apparent diameter from Earth: 2.2 arc seconds
Maximum visual magnitude: 7.78

We’ve written many articles about the Solar System. Here’s an article about how many moons there are in the Solar System, and here’s an article about the formation of the Solar System.

If you’d like more info on the Solar System, check out NASA’s Planetary Fact Sheet.

We’ve recorded several episodes of Astronomy Cast about the Solar System. Start here, Episode 49: Mercury.

Posted on by Fraser Cain

Neptune Fact Sheet

Neptune

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The following Neptune fact sheet is based on NASA’s excellent planetary fact sheets. Neptune is the 8th planet from the Sun, and it requires a telescope to be able to see it.

Mass: 102.43 x 1024 kg
Volume: 6,254 x 1010 km3
Average radius: 24,622 km
Average diameter: 49,244 km
Mean density: 1.638 g/cm3
Escape velocity: 23.5 km/s
Surface gravity: 11.15 m/s2
Natural satellites: 13
Rings? – Yes
Semimajor axis: 4,495,060,000 km
Orbit period: 60,189 days
Perihelion: 4,444,450,000 km
Aphelion: 4,545,670,000 km
Mean orbital velocity: 5.43 km/s
Orbit inclination: 1.769°
Orbit eccentricity: 0.0113
Sidereal rotation period: 16.11 hours
Length of day: 16.11 hours
Axial tilt: 28.32°
Discovery: 23 September 1846
Minimum distance from Earth: 4,305,900,000 km
Maximum distance from Earth: 4,687,300,000 km
Maximum apparent diameter from Earth: 2.4 arc seconds
Minimum apparent diameter from Earth: 2.2 arc seconds
Maximum visual magnitude: 7.78

We’ve written many articles about Neptune for Universe Today. Here’s an article about the color of Neptune, and here’s an article about the atmosphere of Neptune.

If you’d like more info on Neptune, check out Hubblesite’s News Releases about Neptune, and here’s a link to NASA’s Solar System Exploration Guide to Neptune.

We’ve also recorded an entire episode of Astronomy Cast just about Neptune. Listen here, Episode 63: Neptune.

Posted on by Fraser Cain

Uranus Fact Sheet

Uranus, seen by Voyager 2. Image credit: NASA/JPL

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The following Uranus fact sheet is based on NASA’s excellent planetary fact sheets. Uranus is the 7th planet from the Sun, and it requires a telescope to be able to see it.

Mass: 86.832 x 1024 kg
Volume: 6,833 x 1010 km3
Average radius: 25,362 km
Average diameter: 50,724 km
Mean density: 1.270 g/cm3
Escape velocity: 21.3 km/s
Surface gravity: 8.87 m/s2
Natural satellites: 27
Rings? – Yes
Semimajor axis: 2,872,460,000 km
Orbit period: 30,685.4 days
Perihelion: 2,741,300,000 km
Aphelion: 3,003,620,000 km
Mean orbital velocity: 6.81 km/s
Orbit inclination: 0.772°
Orbit eccentricity: 0.0457
Sidereal rotation period: 17.24 hours
Length of day: 17.24 hours
Axial tilt: 97.77°
Discovery: 13 March 1781
Minimum distance from Earth: 2,581,900,000 km
Maximum distance from Earth: 3,157,300,000 km
Maximum apparent diameter from Earth: 4.1 arc seconds
Minimum apparent diameter from Earth: 3.3 arc seconds
Maximum visual magnitude: 5.32

We’ve written many articles about Uranus for Universe Today. Here’s an article about the atmosphere of Uranus, and here’s an article about a blue ring around Uranus.

If you’d like more info on Uranus, check out Hubblesite’s News Releases about Uranus. And here’s a link to the NASA’s Solar System Exploration Guide to Uranus.

We’ve also recorded an entire episode of Astronomy Cast just about Uranus. Listen here, Episode 62: Uranus.

Posted on by Jerry Coffey

How Hot is Jupiter?

Jupiter in visible and infrared

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Given how far Jupiter is from the Sun, you might think that “how cold is Jupiter?” would be a more relevant question and you would be partially right. “How hot is Jupiter?” becomes more relevant the deeper into the planet’s atmosphere and core that you travel. Near the very center of the planet, scientists believe that temperatures can reach 35,500 C.

The outer edges of Jupiter’s atmosphere are much cooler than the core region. Temperatures in the atmosphere are thought to be as cold as -145 degrees C. The intense atmospheric pressure on Jupiter contributes to temperature increases as you descend. Not far into the atmosphere the pressure can be ten times what it is here on Earth and scientists speculate that the temperature is 20 degrees C(average room temperature on Earth). A few hundred km deeper into the planet and hydrogen becomes hot enough to turn into a liquid. The temperature at this point is believed to be over 9,700 C. The layer of dense molten hydrogen metal extends to the 78th percentile of the planet’s radius. Between the cold clouds and the molten lower regions is an interior atmosphere of hydrogen. The hydrogen in this region is at a temperature where there are no distinct liquid and gas phases, so the hydrogen is said to be in a supercritical fluid state.

The molten inner regions of the planet serve to heat the rest of the planet through convection, so Jupiter gives off more heat than it receives from the Sun. This heating prevents it from being an ice giant instead of a gas giant, but wreaks havoc in the atmosphere. Storms and high winds are generated by cool air and warm air mixing here on Earth. Scientist think that the same holds true on Jupiter. The Galileo spacecraft observed winds in excess of 600 kph. One difference is that the jet streams that drive storms and winds on Earth are caused by the Sun heating the atmosphere. On Jupiter it seems that the jet streams are driven by the planets’ own heat. Storms on Jupiter are as out-sized as the planet. The Great Red Spot is a single storm that has been raging for hundreds of years. Other storms have been observed to grow to more than 2,000 km in diameter in a single day.

“How hot is Jupiter?” is more relevant than you may have thought. The planet’s inner heat seems to be the basis for its identity as a stormy world. The actual temperatures of the different areas of the planet may not be a mystery much longer. Hopefully, the recently launched JUNO space mission will clear up many of the Jovian theories that scientists currently have.

We’ve written many articles about the temperature of planets for Universe Today. Here’s an article about how hot Mercury is, and here’s an article about how hot Venus is.

If you’d like more information on Jupiter, check out Hubblesite’s News Releases about Jupiter, and here’s a link to NASA’s Solar System Exploration Guide to Jupiter.

We’ve also recorded an episode of Astronomy Cast just about Jupiter. Listen here, Episode 56: Jupiter.

Sources:
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jupiter
http://www.nasa.gov/mission_pages/juno/main/index.html

Posted on by Jerry Coffey

Jupiter’s Core



Jupiter probably does not have a solid core. Jupiter’s core contains some rock and hydrogen metals. Scientists can not be 100 percent certain if deep within the planet there is a solid core or not, but based on gravitational measurements compared with Earth’s, the best educated guesses possible based on those measurements say there is no solid core. Those measurements make them think that the core is a thick, super hot soup.

Jupiter’s composition is more of a mystery than anything else. The accepted theory holds that it consists of a dense core made of a mixture of elements, the core is thought to be surrounded by a layer of liquid metallic hydrogen and helium, then the outer layer is to be dominated by molecular hydrogen. The core is often speculated to be rocky. It wasn’t until 1997 that the existence of the core was even theorized. Gravitational measurements were taken, indicating a mass in the neighborhood of 12 to 45 times the Earth’s mass, so the proposed core accounts for about 3–15% of the total mass of the planet. The presence of a planetary core follows accepted knowledge of planetary formation. According to this knowledge base, Jupiter would have had to form a rocky or icy core with enough mass in order to capture such a high percentage of gasses from the early solar nebula. Scientists admit that the planet may lack a core at this time due to the high heat and as hot liquid metallic hydrogen mixed with the molten core, carrying it to higher levels of the planet’s interior.

The layer of dense molten hydrogen metal extends to the 78th percentile of the planet’s radius. Just above the layer of metallic hydrogen is an interior atmosphere of hydrogen. The hydrogen at this point is at a temperature where there are no distinct liquid and gas phases, so the hydrogen is in a supercritical fluid state. The temperature and pressure increase steadily toward the core. In the region where hydrogen becomes metallic, the temperatures are thought to be up to 10,000 K and the pressure is 200GPa. The temperature at the core boundary is estimated to be 36,000 K and the pressure is believed to be 3,000 to 4,500 Gpa.

Since very little is known about the composition of Jupiter’s core or even if it still exists, the JUNO space mission was launched on August of 2011. It should arrive in orbit around Jupiter in 2016. The purpose of the mission is to orbit the poles and clear up some of the mysteries surrounding the planet and the entire Jovian system.

We’ve written several articles about planetary cores for Universe Today. Here’s an article about the Earth’s core, and here’s an article about the core of Mercury.

If you’d like more information on Jupiter, check out Hubblesite’s News Releases about Jupiter, and here’s a link to NASA’s Solar System Exploration Guide to Jupiter.

We’ve also recorded an episode of Astronomy Cast all about Jupiter. Listen here, Episode 56: Jupiter.

Source: NASA

Posted on by Jerry Coffey

Weight on Jupiter

Jupiter's Red Spot

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If you are worried about your weight, do not go to Jupiter. The Jovian gravity is much more intense than Earth’s. 2.528 times more intense to be exact. That means if you weigh 100 kg on Earth, your weight on Jupiter would be 252.8 kg.

Of course, you can not stand on the surface of Jupiter. Jupiter is composed of about 90% hydrogen and 9.99% helium. The gaseous nature of the planet makes a solid surface impossible. Scientists have devised a way to define the surface of Jupiter, though. The surface of the planet is defined as the point where the pressure of the atmosphere is 1 bar, which is equal to the atmospheric pressure at Earth’s surface. That point is at the tops of Jupiter’s clouds.

Now that we have defined your weight on Jupiter, let’s move to on some other interesting facts about the planet. To start off, even though it is the largest planet in our Solar System, it is not the largest planet that we know of. While there are several planets larger than Jupiter, the largest known to man is TrES-4. TrES-4 is 70% larger than Jupiter, but is quite a bit less massive. Scientists think that it has a structure similar to cotton candy for lack of a better analogy.

Since Jupiter’s gravity is so intense, it has trapped quite a few moons. The are 63 acknowledged Jovian moons and there are a few others being studied, so that number could go up at any time.

Jupiter has a system of rings. Many people are surprised to find out that Saturn is not the only ringed planet in our Solar System. In addition to Saturn; Jupiter, Uranus, and Neptune have rings. Rings are generally formed by dust and debris left orbiting after a meteorite impact on a moon. With so many moons, you would think that Jupiter would have a bunch of rings. It only has four defined rings, though.

A day on Jupiter is just under 10 Earth hours long, but a single years lasts 11.86 Earth years.

Some scientists think that Jupiter’s gravity is intense enough to affect the Sun. They believe that when Jupiter is at its closest approach to the Sun, solar flare activity increases. Others believe that Jupiter’s gravity may eventually push Mercury our of our Solar System.

Now that you know what your weight on Jupiter would be, we hope that you will want to research more Jovian facts.

We’ve written several articles about your weight on other planets. Here’s an article about your weight on the Moon, and here’s a link about your weight on Mercury.

If you’d like more information on Jupiter, check out Hubblesite’s News Releases about Jupiter, and here’s a link to NASA’s Solar System Exploration Guide to Jupiter.

We’ve also recorded an episode of Astronomy Cast just about Jupiter. Listen here, Episode 56: Jupiter.

Source: NASA

Posted on by Fraser Cain

How Old is Venus?

Solar nebula. Image credit: NASA

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How old is Venus? Scientists actually think that everything in the Solar System was formed at the same time, about 4.6 billion years ago.

Before that point, our entire Solar System was just a vast cloud of hydrogen, helium and other trace elements. Some event, like a nearby supernova, caused the cloud to collapse through its mutual gravity. As the ball collapsed down, it started to spin because of the conservation of momentum from all the atoms in the cloud. As it spun, it flattened out into a disk. The Sun formed out of a bulge in the middle, and the planets formed in the disk.

The planet started out as nothing more than dust, but then these dust particles collided together, forming larger grains, pebbles, rocks, boulders and eventually planetoids. For the first few millions years, the Solar System was a dangerous place with these planetoids constantly crashing into one another. Life wouldn’t stand a chance to survive.

Eventually the number of objects in the Solar System was cleared out; they were either swept up into the planets, or kicked out of the Solar System by gravity. And we were left with the planets we have today.

Astronomers know that everything in the Solar System (including Venus) is roughly 4.6 billion years old through radioactive dating of meteorites. They can tell that all the meteorites in the Solar System were formed at the same time because of the percentages of radioactive elements they contain. And they’re able to determine how much of these radioactive elements have decayed over time, to determine their age.

So, how old is Venus? 4.6 billion years old, just like everything else in the Solar System.

We’ve written many articles about the age of objects in the Universe. Here’s an article about the age of the Universe, and here’s an article about the age of the Milky Way.

If you’d like more info on Venus, check out Hubblesite’s News Releases about Venus, and here’s a link to NASA’s Solar System Exploration Guide on Venus.

We’ve also recorded an episode of Astronomy Cast all about Venus. Listen here, Episode 50: Venus.

Posted on by Fraser Cain

Venus Exploration

The first color pictures taken of the surface of Venus by the Venera-13 space probe. Credit: NASA
The first color pictures taken of the surface of Venus by the Venera-13 space probe. The Venera 13 probe lasted only 127 minutes before succumbing to Venus's extreme surface environment. Part of building a longer-lasting Venus lander is figuring out how to power it. Credit: NASA

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Venus has been know to humanity since we first looked up into the sky; it’s the brightest object in the night sky after the Sun and the Moon, so it’s pretty hard to miss. But Venus exploration really began with the invention of the telescope.

Although he didn’t invent the telescope, Galileo Galilei was the first to point it at the heavens and make detailed observations of what he saw. In 1610 he discovered that Venus goes through phases, like the Moon. This is because Venus is closer to the Sun than the Earth, and so we’re seeing different amounts of the planet illuminated by the Sun. This provided more evidence that the Solar System orbits around the Sun, and not the Earth.

But even with bigger and better telescopes, astronomers weren’t able to penetrate the thick clouds that shroud Venus and see the terrain below. They imagined a warm rainforest jungle world, but astronomers eventually worked out that Venus is really covered in a thick atmosphere of carbon dioxide, and the ground below is heated to hundreds of degrees.

The first spacecraft to arrive at Venus was NASA’s Mariner 2, which flew past Venus in 1962. It was followed by spacecraft from Russia, including several that actually landed on the surface of Venus, and survived up to a few hours in the horrendous heat. NASA’s Magellan spacecraft was equipped with a radar instrument that could pierce through the atmosphere of Venus and reveal the terrain below. It showed that Venus has evidence of volcanism, and impact craters, but no plate tectonics. This helps contribute to its runaway greenhouse effect.

The most recent spacecraft sent to Venus is the European Space Agency’s Venus Express. It arrived at Venus in 2006, and has been making continuous observations of the planet ever since.

We’ve written many articles about the exploration of the planets in the Solar System. Here’s an article about the benefits of space exploration, and here’s an article about the Mars Exploration Rover.

If you’d like more information on the exploration of Venus, check out the homepage for ESA’s Venus Express, and here’s a link to the Venera Program.

We’ve also recorded an entire episode of Astronomy Cast all about Venus. Listen here, Episode 50: Venus.