A fleet of robot spaceships is to descend on Venus in a few years and begin probing the most inhospitable world in the solar system. One craft is to drop through Venus’ crushingly dense and searingly hot atmosphere, while two others are to orbit over the thick, acidic clouds that cover the planet and use sophisticated radar telescopes to survey the terrain beneath them.
Such scrutiny represents a remarkable renewal of interest in Earth’s nearest planetary neighbor. For more than a decade, US and European space agencies have ignored the planet — only for three new Venus missions to be announced within days of each other at the beginning of last month.
Hakan Svedhem, former project manager of Europe’s previous probe to the planet, Venus Express, last month told the science journal Nature: “Venus has been a forgotten planet for too long.”
Illustration: Mountain People
The aim of the new missions — NASA’s Veritas and Davinci+ probes and the European Space Agency’s EnVision satellite — is straightforward. They want to know why Earth’s sibling planet is so utterly different from our own world.
As astronomers knew at the beginning of the “space age” in the 1960s, both planets have the same size, similar ages, compositions and orbits around the sun. Beneath the thick clouds of Venus, it was assumed there could be oceans or forests, and so, a series of robot probes were sent by US and Soviet space agencies to uncover the truth in the 1970s and 1980s.
They revealed a world that was a vision of hell. Venus was found to have a surface temperature of 475?C, which is hot enough to melt lead. At the same time, the atmospheric pressure at its surface is 93 bars, the equivalent to that experienced 1km under the ocean on Earth. Soviet probes that landed on Venus in the 1970s and 1980s managed to transmit data from the planet for only brief periods — two hours was the best they managed — before the heat and crushing pressure destroyed them.
For good measure, Venus was also found to be covered in thick clouds of sulfuric acid. By contrast, our own world possesses oceans of liquid water, clouds and ice caps, and supports myriad forms of living creatures in its seas, on land and in the skies. The differences between the two planets — despite their superficial similarities — could not be more stark.
The key cause of these vastly different sets of conditions is explained by the vast amounts of carbon dioxide that have built up on Venus. This has trapped solar radiation and triggered a runaway greenhouse effect that exists on a scale that utterly dwarfs the impact of the climate crisis that is now disrupting weather patterns and melting ice caps on Earth.
How did this buildup of carbon dioxide occur, scientists ask. Did Earth get lucky or was it the case that Venus was just unlucky? Is it the norm for planets in orbits like those of Venus and Earth to develop thick atmospheres of carbon dioxide that trap solar radiation and trigger runaway greenhouse effects — or was it just a one-off development in the case of Venus?
“These are key questions and they have important ramifications, not just in understanding how life appeared and evolved on Earth,” said Colin Wilson, a senior research fellow in the University of Oxford’s physics department. “They also have implications for searching for habitable planets in orbit around other stars in our galaxy.”
At present, astronomers pin their hopes of finding promising planets that might support life elsewhere in the galaxy by seeking out small rocky worlds — like Earth — that orbit stars at a distance in which water is likely to exist in liquid form. However, judging from the only other world in our solar system that is found in such a zone — Venus — that might not be such a promising locale, after all. In other words, if Earth is the exception and Venus the norm, we might find that such planets are far less encouraging as hosts for alien life.
This point was stressed by Giada Arney, deputy principal investigator for the Davinci+ probe.
“Our investigation of the evolution of Venus may help us better understand how habitable worlds are distributed elsewhere in the universe, and how habitable planets evolve over time in a general sense,” she said.
However, it might be that Venus was simply in the wrong place. Being closer to the sun than the Earth — 108 million kilometers versus 152 million kilometers — made it slightly warmer when it formed during the solar system’s birth 4.5 billion years ago.
As a result, the water vapor in its atmosphere never condensed into oceans as it did on Earth, where our seas played a key role in absorbing carbon dioxide and prevented runaway greenhouse heating.
Other evidence hints that Venus might have had liquid water on its surface at one time, and that some other event set off the rampant warming that now envelops the planet. The three new probes would try to uncover clues as what they might be.
“Studying the planet’s surface will be crucial,” Wilson said. “The US Magellan probe — which arrived at Venus in 1989 — used radar to peer through the clouds and give us a wonderful global map of Venus, which revealed volcanoes and a fractured surface that had clearly gone through lots of turmoil. But it was just a snapshot.”
“We don’t know if those volcanoes are still active, for example. The new space probes will take 21st-century radar technology and apply it to Venus, and give us a much more dynamic picture of the planet,” he said.
This point was backed by Cardiff University astronomy professor Jane Greaves.
“Some instruments, such as radar and mass spectrometers, have already been used to study Venus in the past, but their technology today is so much better and more sophisticated. We will be able to probe deeper and identify molecules more easily,” she said.
Veritas and EnVision would be involved in mapping Venus’ surface from an orbit high above its acid clouds. By contrast, Davinci+ would carry a small probe to the planet that it would release so that it parachutes down through its atmosphere, sampling its component gases every 100m as it descends. These measurements will be crucial in understanding the origins of Venus’ atmosphere and provide clues about its evolution.
For example, by studying levels of deuterium, an isotope of hydrogen, it should be possible to determine how much water there once was on Venus, while analysis of noble gases, such as argon and neon, in the atmosphere might also allow scientists to determine if the planet once supported liquid water — data that would be crucial in providing clues about Venus’s path to the dark side.
“It is astounding how little we know about Venus,” said Tom Wagner, a scientist working for the NASA Discovery Program.
“However, the combined results of these missions will tell us about the planet from the clouds in its sky through the volcanoes on its surface all the way down to its very core. It will be as if we have rediscovered the planet,” he said.
In an article published in Newsweek on Monday last week, President William Lai (賴清德) challenged China to retake territories it lost to Russia in the 19th century rather than invade Taiwan. “If it is really for the sake of territorial integrity, why doesn’t China take back Russia?” Lai asked, referring to territories lost in 1858 and 1860. The territories once made up the two flanks of northern Manchuria. Once ceded to Russia, they became part of the Russian far east. Claims since then have been made that China and Russia settled the disputes in the 1990s through the 2000s and that “China
China has successfully held its Forum on China-Africa Cooperation, with 53 of 55 countries from the African Union (AU) participating. The two countries that did not participate were Eswatini and the Sahrawi Arab Democratic Republic, which have no diplomatic relations with China. Twenty-four leaders were reported to have participated. Despite African countries complaining about summit fatigue, with recent summits held with Russia, Italy, South Korea, the US and Indonesia, as well as Japan next month, they still turned up in large numbers in Beijing. China’s ability to attract most of the African leaders to a summit demonstrates that it is still being
Trips to the Kenting Peninsula in Pingtung County have dredged up a lot of public debate and furor, with many complaints about how expensive and unreasonable lodging is. Some people even call it a tourist “butchering ground.” Many local business owners stake claims to beach areas by setting up parasols and driving away people who do not rent them. The managing authority for the area — Kenting National Park — has long ignored the issue. Ultimately, this has affected the willingness of domestic travelers to go there, causing tourist numbers to plummet. In 2008, Taiwan opened the door to Chinese tourists and in
Taiwan People’s Party (TPP) Chairman Ko Wen-je (柯文哲) on Thursday was handcuffed and escorted by police to the Taipei Detention Center, after the Taipei District Court ordered that he be detained and held incommunicado for suspected corruption during his tenure as Taipei mayor. The ruling reversed an earlier decision by the same court on Monday last week that ordered Ko’s release without bail. That decision was appealed by prosecutors on Wednesday, leading the High Court to conclude that Ko had been “actively involved” in the alleged corruption and it ordered the district court to hold a second detention hearing. Video clips
RSS