{"id":27926,"date":"2019-08-30T21:50:24","date_gmt":"2019-08-30T21:50:24","guid":{"rendered":"https:\/\/one.sightlinemg.com\/navytimes\/uncategorized\/2019\/08\/30\/op-ed-get-back-to-venus\/"},"modified":"2026-08-08T19:20:50","modified_gmt":"2026-08-08T19:20:50","slug":"op-ed-get-back-to-venus","status":"publish","type":"post","link":"https:\/\/one.sightlinemg.com\/navytimes\/news\/your-navy\/2019\/08\/30\/op-ed-get-back-to-venus\/","title":{"rendered":"Let\u2019s get back to Venus!"},"content":{"rendered":"\n

Just next door, cosmologically speaking, is a planet almost exactly like Earth<\/a>. It\u2019s about the same size, is made of about the same stuff and formed around the same star.<\/p>\n\n\n\n

To an alien astronomer light years away, observing the solar system through a telescope, it would be virtually indistinguishable from our own planet. But to know the surface conditions<\/a> of Venus \u2013 the temperature of a self-cleaning oven, and an atmosphere saturated with carbon dioxide with sulfuric acid clouds \u2013 is to know that it\u2019s anything but Earth-like.<\/p>\n\n\n\n

So how is it that two planets so similar in position, formation and composition can end up so different? That\u2019s a question that preoccupies an ever-growing number of planetary scientists, and motivates numerous proposed Venus exploration efforts<\/a>. If scientists can understand why Venus turned out the way it did, we\u2019ll have a better understanding of whether an Earth-like planet is the rule \u2013 or the exception.<\/p>\n\n\n\n

I\u2019m a planetary scientist<\/a>, and I\u2019m fascinated by how other worlds came to be. I\u2019m particularly interested in Venus, because it offers us a glimpse of a world that once might not have been so different from our own.<\/p>\n\n\n\n

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This global view of the surface of Venus is centered at 180 degrees east longitude. Magellan synthetic aperture radar mosaics from the first cycle of Magellan mapping are mapped onto a computer-simulated globe to create this image. (NASA\/Jet Propulsion Laboratory-Caltech)<\/figcaption><\/figure>\n\n\n\n

A once-blue Venus?<\/b><\/i><\/p>\n\n\n\n

The current scientific view of Venus holds that, at some point in the past, the planet had much more water than its bone-dry atmosphere suggests today \u2013 perhaps even oceans<\/a>. But as the Sun grew hotter and brighter (a natural consequence of aging), surface temperatures rose on Venus, eventually vaporizing any oceans and seas.<\/p>\n\n\n\n

With ever more water vapor in the atmosphere, the planet entered a runaway greenhouse<\/a> condition from which it couldn\u2019t recover. Whether Earth-style plate tectonics (where the outer layer of the planet is broken into large, mobile pieces) ever operated on Venus is unknown.<\/p>\n\n\n\n

Water is critical for plate tectonics to operate, and a runaway greenhouse effect would effectively shut down that process had it operated there.<\/p>\n\n\n\n

But the ending of plate tectonics wouldn\u2019t have spelled the end of geological activity: The planet\u2019s considerable internal heat continued to produce magma, which poured out as voluminous lava flows and resurfaced most of the planet.<\/p>\n\n\n\n

Indeed, the average surface age of Venus is around 700 million years \u2013 very old, certainly, but much younger than the multi-billion-year-old surfaces of Mars, Mercury or the Moon.<\/p>\n\n\n\n

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Left: True color image of Venus taken by Mariner 10. Right: Venus as imaged by Mariner 10 using an ultraviolet filter\nto highlight the clouds that are invisible in the visible spectrum. (National Aeronautics and Space Administration)<\/figcaption><\/figure>\n\n\n\n

The exploration of Planet 2<\/b><\/i><\/p>\n\n\n\n

The Venus-as-a-wet-world view is just a hypothesis: Planetary scientists don\u2019t know what caused Venus to differ so much from Earth, nor even if the two planets really did start off with the same conditions.<\/p>\n\n\n\n

Humans know less about Venus than we do about the other inner solar system planets, largely because the planet poses several unique challenges to its exploration.<\/p>\n\n\n\n

For example, radar<\/a> is needed to pierce the opaque, sulfuric acid clouds and see the surface. That\u2019s a lot trickier than the readily visible surfaces of the Moon or Mercury<\/a>.<\/p>\n\n\n\n

And the high surface temperature \u2013 470 degrees Celsius (880 degrees Fahrenheit) \u2013 means that conventional electronics don\u2019t last more than a few hours.<\/p>\n\n\n\n

That\u2019s a far cry from Mars, where rovers can operate for more than a decade<\/a>. In part because of the heat, acidity and obscured surface, then, Venus hasn\u2019t enjoyed a sustained program of exploration over the past couple of decades.<\/p>\n\n\n\n

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The hemispheric view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered on the North Pole. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). (NASA\/JPL\/USGS)<\/figcaption><\/figure>\n\n\n\n

That said, there have been two dedicated Venus missions in the 21st century: the European Space Agency\u2019s Venus Express<\/a>, which operated from 2006 to 2014, and the Japan Aerospace Exploration Agency\u2019s Akatsuki spacecraft<\/a> currently in orbit <\/a>.<\/p>\n\n\n\n

Humans haven\u2019t always ignored Venus.<\/p>\n\n\n\n

It was once the darling of planetary exploration: between the 1960s and 1980s, some 35 missions were dispatched to the second planet.<\/p>\n\n\n\n

The NASA Mariner 2 mission<\/a> was the first spacecraft to successfully carry out a planetary encounter when it flew past Venus in 1962.<\/p>\n\n\n\n

The first images returned from the surface of another world were sent from the Soviet Venera 9 lander<\/a> after it touched down in 1975.<\/p>\n\n\n\n

And the Venera 13 lander<\/a> was the first spacecraft to return sounds from the surface of another world. But the last mission NASA launched to Venus was Magellan<\/a> in 1989. That spacecraft imaged almost the entire surface with radar before its planned demise in the planet\u2019s atmosphere in 1994.<\/p>\n\n\n\n

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Venus crossed the left limb of the sun, seen here at 304 angstroms, between 6 and 7 p.m. EDT on June 5, 2012. (NASA)<\/figcaption><\/figure>\n\n\n\n

Back to Venus?<\/b><\/i><\/p>\n\n\n\n

In the last few years, several NASA Venus missions have been proposed. The most recent planetary mission that NASA chose is a nuclear-powered craft called Dragonfly<\/a>, destined for Saturn\u2019s moon Titan. However, one proposal to measure the composition of the Venus surface was selected for further technology development<\/a>.<\/p>\n\n\n\n

Other missions being considered include one by the ESA to map the surface at high resolution<\/a>, and a Russian<\/a> plan to build on its legacy<\/a> as the only country to successfully put a lander on Venus\u2019 surface.<\/p>\n\n\n\n

Some 30 years after NASA set course for our hellish neighbor, the future of Venus exploration looks promising. But a single mission \u2013 a radar orbiter or even a long-lived lander<\/a> \u2013 won\u2019t solve all the outstanding mysteries.<\/p>\n\n\n\n

Rather, a sustained program of exploration is needed to bring our knowledge of Venus to where we understand it as well as Mars or the Moon. That will take time and money, but I believe it\u2019s worth it. If we can understand why and when Venus came to be the way it is, we\u2019ll have a better grasp of how an Earth-size world can evolve when it\u2019s close to its star<\/a>.<\/p>\n\n\n\n

And, under an ever-brightening Sun, Venus may even help us understand the fate of Earth itself.<\/p>\n\n\n\t