The second planet from the sun is another example of the Lord’s creativity and resists secular origins scenarios. Venus appears as a bright and stunningly beautiful star in Earth’s sky. For this reason, it was named for the Roman goddess of love and beauty. Being nearly the size of Earth, and the closest planet to Earth, Venus has been the subject of many stories – especially in science fiction. The second book of C.S. Lewis’s excellent space trilogy takes place on Venus. In reality, Venus turns out to be far more interesting than any science fiction writer could have imagined.
Observing Venus
Since Venus is the third brightest object regularly seen in our sky, with only the sun and moon being brighter, it is very easy to see. In fact, at certain times, it is possible to see Venus in broad daylight if you know where to look. But the easiest times to see Venus are in the western sky shortly after sunset (when Venus is to the east of the sun), or in the eastern sky shortly before sunrise (when Venus is west of the sun). For this reason, Venus is often called the evening star, or the morning star. It is even referred to as such in Scripture (Revelation 2:28, 22:16).[1] At the time this article is posted, Venus currently appears as the spectacularly bright evening star in the west after sunset.
Venus is a wonderful object to view with a small telescope. Being exceptionally bright, it is easy to find. And a telescope reveals that Venus goes through phases, much like the moon. Indeed, first-time viewers of Venus often remark that it looks like a tiny, craterless version of the moon. In fact, the surface of Venus does have craters along with valleys and mountains. But you will never see the rocky surface of this planet in your telescope because Venus is permanently enshrouded in thick clouds. These clouds are highly reflective, which is one reason why Venus is so bright.
Venus is 95% the size of Earth in diameter. I often think of this fact when I observe Venus through a telescope. It appears about the same size as the Earth would look if we could view it from Venus. Venus is significantly brighter than Mercury. Even though Venus is farther from the sun and thus receives less sunlight per unit of surface area, it is two and half times the size of Mercury. And the clouds of Venus are far more reflective of sunlight than the dark, rocky surface of Mercury. Furthermore, Venus comes much closer to Earth than Mercury, closer than any other planet.
Venus orbits the sun every 224.7 (Earth) days at an average distance of 67 million miles. Its orbit is the most circular of any planet in our solar system, with an eccentricity of only 0.006772. It orbits in the same direction as Earth, the same direction as all the planets. But since it orbits faster than the Earth, Venus laps the Earth every 584 days. So if you see Venus as the evening star, you will again see it as the evening star in 584 days.
Like Mercury, Venus occasionally passes directly in front of the sun as viewed from Earth – an event called a solar transit. However, Venus transits are rarer than Mercury transits, and they are far more spectacular since Venus is two and half times larger than Mercury. Venus transits occur only twice in a century, always separated by 8 years. The last two were in 2004, and 2012. The next pair of transits will be in December 2117 and December 2125.
The Phase of Venus
In the early 1600s, Galileo observed the phases of Venus using his homemade telescope. These phases confirmed what Galileo already suspected: the planets orbit the sun, not the Earth. At that time in history, most astronomers held to a geocentric solar system; they believed that the Earth was stationary and that all the (other) planets and the sun orbited Earth. In particular the Greek astronomy Ptolemy had developed a detailed model of a geocentric solar system that was largely successful in predicting the positions of planets over time. However, Ptolemy’s geocentric model predicted that Venus should never experience a gibbous phase (in which more than 50% of the surface is illuminated by the sun) because Venus was never on the far side of the sun as seen from Earth.
But in fact, Venus goes through all phases, like the moon. Unlike the moon, however, Venus appears very small when in its gibbous or full phases, larger when it is in first or third quarter, and much larger when it is in a crescent phase. This only makes sense if Venus orbits the sun. In its gibbous and full phases, it is on the far side of the sun, at great distance from Earth and therefore appears small. When appearing as a crescent, Venus is clearly on the same side of the sun as Earth, and therefore appears large due to its proximity. If you have even a very small telescope, you can confirm this for yourself by observing Venus at various dates over a period of several months.
Physical Properties
Venus has been called Earth’s sister planet because they are so similar in size and both have a rocky composition. The surface gravity of Venus is a comfortable 90% that of Earth. Both planets orbit relatively close to the sun. Both have a substantial atmosphere, unlike Mercury or the moon. Both planets have mountains and volcanos. But the differences between these two worlds are legion.
The axial tilt of Venus is less than three degrees. That is, its rotation axis is nearly aligned with the axis of its orbit around the sun. A large axial tilt causes seasons on planets like Earth and Mars. So Venus has no seasons. Venus has a massive atmosphere of primarily carbon dioxide, over ninety times the mass of Earth’s atmosphere. Consequently, the atmospheric pressure on the surface of Venus is over ninety times that of Earth at sea level.
Since carbon dioxide is a mild greenhouse gas, the massive atmosphere of Venus generates a powerful greenhouse effect. The surface temperature of Venus can exceed 900 degrees Fahrenheit – that’s even hotter than the hottest part of Mercury. The dense atmosphere and high wind speeds distribute this extreme heat over the entire surface of Venus. So, Venus is essentially uniformly hot, from pole to equator, with no substantial difference between day and night. Some people are very concerned that the Earth might someday experience a similar runaway greenhouse effect. But this is impossible for Earth considering its atmosphere is just over 1% that of Venus. And less than 1% of that 1% is carbon dioxide. Earth’s atmosphere is mainly comprised of nitrogen and oxygen which are not greenhouse gases.
The clouds that reside in Venus’s toxic atmosphere are comprised of sulfuric acid and similar compounds. They completely enshroud Venus at all times, meaning the sky would be permanently overcast. You could never see the sun from the surface of Venus. The thickness of the atmosphere also causes substantial bending of light. This effect happens on Earth too, but is barely noticeable. On Venus, the refraction of light in the atmosphere is so severe that an observer could (in principle) see the entire surface of the planet from any one point on the planet. It would seem like standing in the bottom of a large, shallow valley, where the surface rises with distance rather than dropping with distance. The entire surface of the planet would appear to bend upwards, with no distinct horizon.
With clouds of sulfuric acid, a crushing atmosphere of toxic and unbreathable carbon dioxide, and a surface temperature that can reach 900 degrees Fahrenheit, Venus is clearly not designed for life. It’s hardly the paradise that many people in the early 20th century hoped it would be. Rather, it is the planet in our solar system that is probably most like hell. So, Earth’s sister planet turns out to be more like a wicked stepsister. Of course, God didn’t create Venus to be inhabited; that is the function of Earth (Isaiah 45:18). What Venus is designed to do, it does very well.[2]
An Unusual Day
Venus has a very unusual rotation. Venus rotates once every 243 Earth days, so its sidereal day is actually longer than its year. Venus has the slowest rotation of any known planet. Moreover, Venus rotates backwards – the opposite direction of its orbit around the sun. This is called retrograde rotation. All planets revolve around the sun in a counter-clockwise direction as viewed over the north pole of the solar system. Most planets also rotate in this direction, as does the sun; this is called prograde rotation. Venus is the exception.[3]
Retrograde rotation challenges the most common secular origins story. In the secular view, all the planets formed from one collapsing, rotating cloud of gas. This rotation should be preserved in the way the planets orbit and rotate. This is due to an important principle in physics called the conservation of angular momentum. Think of it as the rotational equivalent of Newton’s first law: a rotating object will continue to rotate in the same direction and with the same angular momentum unless acted upon by an outside torque. For this reason, any planets that form from a rotating cloud should be spinning in the same direction. Furthermore, they should have no axial tile. But Venus rotates exactly the opposite of the secular prediction. The Lord seems to delight in making things that both exhibit His creativity and confound unbelievers.
The retrograde rotation of Venus means that its solar day is shorter than its sidereal day – another unique feature. That is, if you could somehow survive on the surface of Venus, and could peer through the clouds, the time from one sunrise to the next would be 117 Earth days – just over half of its year. Of course, the sun would rise in the west, and set in the east – the opposite of what we experience on Earth. But again, you would never see the sun because of the clouds. The other planets rotate prograde, and so their solar day is longer than their sidereal day. Hence, Venus has the longest sidereal day, but Mercury has the longest solar day. Venus and Mercury are the only two planets in our solar system that have no moon.
Visits by Spacecraft
There have been 27 successful unmanned missions to Venus.[4] The first successful mission was the Mariner 2 flyby mission. The former Soviet Union was very interested in Venus, and orchestrated nearly 30 missions to this planet; less than half were successful. The Venera 9 craft successfully landed on Venus in 1975 and was able to take photographs of the surface.[5] These are the first images from the surface of another planet. The Soviets had several other lander missions with varying degrees of success. To design a craft to withstand the crushing toxic atmosphere in temperatures up to 900 degrees Fahrenheit, if only for a couple of hours, is a remarkable achievement. No other nations have attempted to land a probe on Venus.
Some of the missions to Venus involved orbiters – spacecraft that were injected into an orbit around Venus. This allows for a much longer and more extensive study of the planet than a quick fly-by mission. One of the most well-known and successful orbital missions to Venus involved the Magellan spacecraft. Launched on May 4, 1989, the spacecraft was injected into orbit around Venus on August 10, 1990. It then began a four-year mission of mapping the surface of Venus using radar. Unlike visible light, radar passes directly through clouds, and reflects off of the rocky surface.
You have probably seen the resulting radar map of the surface of Venus, usually presented in various tones of orange and brown. In fact, I have seen many publications in which this image is used along with visible-light images of the other planets, implying that this is actually what Venus looks like. It isn’t. The image is a radar-map. The actually appearance of Venus is a nearly uniform pale yellow due to the thick clouds.
By recording the precise timing of the reflected beam, Magellan was able to construct a nearly-complete, high-resolution topographical map of Venus. This map reveals that Venus has two large “continental” highlands. So, if Venus weren’t so hot and had oceans like Earth, it would have two enormous continents. One of these is in the northern hemisphere and is named Ishtar Terra. The other is just south of the equator and has been named Aphrodite Terra. Ishtar is the Babylonian goddess of love whereas Aphrodite is the Greek goddess of love – both the equivalent of the Roman Venus.
The surface of Venus has some impact craters, but also has a number of volcanoes – far more than the Earth. The volcanoes on Venus have a unique pancake shape. Several other unique features include radial spoke-like fractures; sometimes these include concentric rings vaguely resembling spider webs. These features are thought to be volcanic in origin. We have not observed any active volcanoes on Venus. Then again, the clouds of Venus prevent direct observations in visible light. However, there is some evidence of recent volcanic activity; sulfur dioxide has been detected in the atmosphere of Venus in levels that change drastically over time.
Venus is thought to have an internal structure similar to that of Earth, with a crust, mantle, and core. However, the crust of Venus is thought to be very thick, and Venus exhibits no evidence of plate tectonics. Venus is one of two planets in our solar system that lack a global magnetic field – the other being Mars. Venus may have had a magnetic field when the Lord first created it. But magnetic fields naturally decay with time. They decay faster for smaller planets, and the rate also depends on the planet’s composition. We may find evidence of remanent magnetism on Venus (as we do on Mars), indicating a past global magnetic field that has dissipated in the thousands of years since creation.
A World of Contrast
When we consider the extreme temperatures, the crushing
unbreathable atmosphere, and acidic clouds of Venus, we cannot help but
contrast this with the richness and beauty of Earth. Venus and Earth are very similar in size and
overall composition, and their respective orbits are similar. But the surface of Venus is hostile to life,
whereas the surface of Earth is uniquely designed for life. Keep this in mind when you hear reports of
astronomers discovering an Earth-sized planet orbiting some distant star. Planets that orbit other stars are far too
distant for us to image with any detail.
In most cases, the only thing we know about extra-solar planets is their
mass, their orbital characteristics, and in some cases their size. Secular astronomers hope to find a planet
much like Earth; but these Earth-sized planets may turn out to be similar to
Venus, or perhaps as different from both Earth and Venus as these two planets
are from each other. Rather, the planets
in our own solar system and any others demonstrate the creativity of the Lord.
[1] The “morning star” or a similar phrase is mentioned in some English translations of 2 Peter 1:19, and Isaiah 14:12. However, unlike the passages in Revelation, these are not literal translations of “morning” nor “star” from the original languages.
[2] Genesis 1:14-19; Psalm 19:1
[3] In some sense, Uranus could also be considered an exception. Uranus rotates on its side. Its rotation axis is tilted more than 90 degrees relative to its orbit around the sun. Alternatively, one could consider Uranus to be tilted slightly less than 90 degrees, and rotating in the opposite direction. It depends on which pole we consider to be the north pole.
[4] For some of these, Venus was not the primary target, but was used as a gravitational assist to slingshot the craft to another planet.
[5] ‘Venera’ means ‘Venus’ in Russian.