قالب وردپرس درنا توس
Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Has Venus ever been inhabited? | space

Has Venus ever been inhabited? | space



<! –

->

  Blue ball with orange-brown slits on a black background.

The concept of the artist for the ancient planet Venus, with a shallow ocean. Image via NASA.

The second planet out of our sun – Venus, named after the Roman goddess of love ̵

1; is close to twins on Earth in size and density. But this is a hell of a place, with thick clouds of carbon dioxide coated with sulfuric acid. Its surface pressure is 90 times higher than the earth's surface, and its surface temperatures are hot enough to melt lead. And yet – last week at NASA's Geneva, Switzerland, astronomers meeting, NASA's Michael Way presented a completely different perspective on Venus. He said on September 20, 2019, that new research reveals that Venus may have once been a temperate world, more like Earth, with shallow liquid water on its surface for about 2 to 3 billion years. A new study suggests that just about 700 million years ago, a dramatic transformation began for Venus, which eventually emerged around 80% of our sister world. These scientists stated in a statement that their study:

… gave a new look at the climatic history of Venus and could have an impact on the habitat of exoplanets in similar orbits.

This is not the first time scientists have considered the liquid water of Venus. NASA's Pioneer-Venus mission – which visited the planet 40 years ago – has found harrowing hints of a long-lost shallow ocean. To see if Venus may have ever had a stable climate capable of holding liquid water, Way and his colleague Anthony Del Genio have created five different computer simulations of Venus in the past. Each assumes a different level of water coverage. In all five scenarios, these scientists found that Venus was able to maintain stable temperatures between a maximum of about 122 degrees Fahrenheit (50 degrees C) and a minimum of about 68 degrees F (20 degrees C) for about three billion years.

Hotter than Earth, yes, but far from the average temperature of 865 ° F (462 degrees C) on Venus today. If one of these scenarios describes something close to Venus in the past, what happened to change things?

  Image of a spaceship on a lifeless, dry, rocky planetary surface, under a yellow sky.

This modified image is based on a first-of-its-kind image from the surface of Venus returned by the spacecraft Soviet Venus 9 in 1975. It looks raw, doesn't it? Image through Venus 9 and Ted Stork's blog Read more about this image from Planetary Society.

According to these scientists, Venus may have maintained its temperate climate to this day, if not for the series of events that caused the release or "excess" of carbon dioxide stored on the planet's rocks about 700 to 750 million years ago.

As we all must know by now, carbon dioxide is a greenhouse gas: it captures heat.

The cause of this defilement is a mystery, these scientists said, but it may be related to the volcanic activity of Venus:

One possibility is that large quantities of magma are blown away, releasing carbon dioxide from molten rocks in the atmosphere, it hardens before it reaches the surface and this creates a barrier which means that the gas cannot be reabsorbed. The presence of large amounts of carbon dioxide triggers the escape of the greenhouse effect, leading to the scorching 462-degree average temperatures found today on Venus.

Did it happen ? Was Venus more moderate in the past? We do not know Computer simulations like these serve to show not what has happened but what could have happened . Scientists acknowledge "two major unknowns:"

The first relates to how fast Venus cools initially and whether it is able to condense liquid water to its surface. The second is unknown if the global resurgence event was a single event or just the latest in a series of events that have passed billions of years in Venus history.

  Orange image of a large shielded volcano with visible lava flows against a black sky.

Although we have not yet discovered an active volcano of Venus, we do know that Venus has volcanic characteristics and that volcanoes have been active there recently, geologically, over the last several million years. In fact, it is known by now that Venus has more volcanoes than any other planet in our solar system: over 1600 major volcanoes. Here is Maat Mons of Venus, the highest volcano of Venus, 5 miles (8 km) high. This perspective view is based on Magellan's radar images. Read more through NASA's PhotoJournal.

Way and his team also acknowledged in their statement that many researchers believe that Venus is beyond the inner boundary of the habitable zone of our solar system; in other words, it is assumed that Venus is too close to the sun to hold liquid water. The new study suggests otherwise. Way says:

At the moment, Venus has almost twice the amount of solar radiation we have on Earth. However, in all the scenarios we have modeled, we have found that Venus can still maintain surface temperatures subject to liquid water.

This finding, if supported by other scientific work, may have implications for our understanding of exoplanets orbiting distant solar energy systems. Have you heard of the Goldilocks area or the habitable zone? This is the area around a star in which the orbits of planets are able to maintain liquid water on their surfaces. It's not too hot, it's not too cold, in other words. We may not understand the true boundary of the habitable zone, either in the direction of the central star of the solar system, or in the other direction, or in both directions. Perhaps our understanding of habitats needs tweaking.

Of course, these scientists said, because scientists almost always say at the conclusion of each study that more research is needed. Way said:

We need more missions to study Venus and understand its history and evolution in more detail.

However, our models show that there is a real possibility that Venus was habitable and radically different from the Venus we see today. This opens up all kinds of consequences for exoplanets in the so-called. Venus Zone, which may actually host liquid water and a temperate climate.

  Bright Venus in the dusk with an extremely thin and fragile moon beneath it.

Venus is the brightest planet visible in the sky on Earth. Only the moon overshadows it at night. Our friend Jenny Dissimon caught the moon and Venus on June 2, 2019 from Kota Kinabalu, Sabah, N. Borneo. The extraordinary brightness for Venus stems in part from its highly reflecting clouds, which capture heat near the planet, raising temperatures. Read more about this when we can see Venus in Heaven again in EarthSky's monthly travel guide.

Bottom line: Venus is a hell of a world today. Has there ever been a stable climate or liquid water? To learn more, scientists have created a series of 5 simulations using different levels of water coverage. In all 5 models, Venus maintains a relative temperature of moderate temperatures for about 3 billion years.

Through the Europlanet Society

  Deborah Bird


Source link