Frequent contributor to Fox News Steven Milloy retweeted a Politico story about climate change to suggest that CO2 won’t kill Earth because Venus is made of CO2 — the only trouble is humans don’t live on Venus, as far as we know.
Milloy is no stranger to ignoring accurate and verified scientific truths. A lawyer and frequent commentator for Fox News, he refers to himself as a libertarian thinker and runs a twitter account called @JunkScience through which he ironically, but not facetiously, often peddles what mosts scientists would refer to as junk science. His close financial and organizational ties to tobacco and oil companies have been the subject of criticism from a number of sources going back to the early 2000s, as Milloy has consistently disputed the scientific consensus on climate change and the health risks of second-hand smoke. Having close ties to tobacco and oil, it’s not difficult to understand why.
Among the topics Milloy has addressed are what he believes to be false claims regarding DDT, global warming, Alar, breast implants, second-hand smoke, ozone depletion, and mad cow disease. This time, however, he attempts to equate planet Earth with planet Venus, saying that CO2 won’t destroy the Earth because Venus is largely made up of CO2.
DeFazio on climate: "This is the existential threat to the future of the planet."
For comparison, the atmosphere Venus is 96.5% CO2 — and the planet is still there.
The obvious problem to scientists (and most people with a high school science education) is that humans don’t live on Venus, and couldn’t since it is so darn hot, hailing an average temperature of 864 degrees Fahrenheit.
It’s obvious that Milloy is being paid to promote bad science in an effort to persuade Fox News watchers into believing that climate change is a hoax. The trick he uses here is to make it seem like people who believe in man-induced global warming through greenhouse gases such as carbon dioxide think the Earth will cease to exist with too much CO2. That isn’t what climate change scientists and activists think at all.
On the contrary, climate change scientists and activists are concerned about human and animal life will cease to exist — the way it doesn’t exist on Venus.
The danger in having to explain this to people is that it’s easier to look at things Milloy’s way. Despite it being wrong, lazy thinkers will read what he tweets and hear what he says on Fox News without doing anymore research or thinking on the matter. When people say convincing things with authority, it usually doesn’t matter if what they’re saying is true or not.
For the first time in history, NASA has discovered a total of eight planets orbiting a distant star that is much like our Sun, the space agency announced on Thursday.
The star, Kepler-90, is 2,545 light-years from Earth and located in the Draco constellation. It is the first star known to humans to support just as many planets as the known Solar System, but what is exciting to many is that astronomers believe that this is in fact only the beginning of a long line of discoveries to come out of our latest technological advances.
For a time, researchers had known that a total of seven planets were orbiting Kepler-90, but Google Artificial Intelligence had a hand in discovering the eighth planet when it looked into archival data originally obtained by NASA’s Kepler telescope, designed specifically to look for planets.
With the idea of eventually differentiating among exoplanets, Christopher Shallue, senior software engineer at Google AI in California, and Andrew Vanderburg, astronomer and NASA Sagan postdoctoral fellow at the University of Texas, Austin, trained a computer how to differentiate between images of cats and dogs, refining their approach to identify exoplanets in Kepler data based on the change in light when a planet passed in front of its star. The neural network learned to identify these by using signals that had been vetted and confirmed in Kepler’s planet catalog. Ninety-six percent of the time, it was accurate.
A new study shows that an atmosphere was produced around the ancient Moon, 3 to 4 billion years ago, when intense volcanic eruptions spewed gases above the surface faster than they could escape to space. The study, supported by NASA’s Solar System Exploration Research Virtual Institute, was published in Earth and Planetary Science Letters.
When one looks up at the Moon, dark surfaces of volcanic basalt can be easily seen to fill large impact basins. Those seas of basalt, known as maria, erupted while the interior of the Moon was still hot and generating magmatic plumes that sometimes breached the lunar surface and flowed for hundreds of kilometers. Analyses of Apollo samples indicate those magmas carried gas components, such as carbon monoxide, the ingredients for water, sulfur, and other volatile species.
In new work, Dr. Debra H. Needham, Research Scientist of NASA Marshall Space Flight Center, and Dr. David A. Kring, Universities Space Research Association (USRA) Senior Staff Scientist, at the Lunar and Planetary Institute (LPI), calculated the amounts of gases that rose from the erupting lavas as they flowed over the surface and showed that those gases accumulated around the Moon to form a transient atmosphere. The atmosphere was thickest during the peak in volcanic activity about 3.5 billion years ago and, when created, would have persisted for about 70 million years before being lost to space.
The two largest pulses of gases were produced when lava seas filled the Serenitatis and Imbrium basins about 3.8 and 3.5 billion years ago, respectively. The margins of those lava seas were explored by astronauts of the Apollo 15 and 17 missions, who collected samples that not only provided the ages of the eruptions, but also contained evidence of the gases produced from the erupting lunar lavas.
NASA’s Needham says, “The total amount of H2O released during the emplacement of the mare basalts is nearly twice the volume of water in Lake Tahoe. Although much of this vapor would have been lost to space, a significant fraction may have made its way to the lunar poles. This means some of the lunar polar volatiles we see at the lunar poles may have originated inside the Moon.”
David Kring notes, “This work dramatically changes our view of the Moon from an airless rocky body to one that used to be surrounded by an atmosphere more prevalent than that surrounding Mars today.” When the Moon had that atmosphere, it was nearly 3 times closer to Earth than it is today and would have appeared nearly 3 times larger in the sky.
This new picture of the Moon has important implications for future exploration. The analysis of Needham and Kring quantifies a source of volatiles that may have been trapped from the atmosphere into cold, permanently shadowed regions near the lunar poles and, thus, may provide a source of ice suitable for a sustained lunar exploration program. Volatiles trapped in icy deposits could provide air and fuel for astronauts conducting lunar surface operations and, potentially, for missions beyond the Moon.
Over the past decade, the search for volatiles within the Moon and on the surface of the Moon has intensified. Those volatiles may hold clues about the material that accreted to form the Earth and Moon and, thus, our planetary origins. The volatiles may also provide the in-situ resources needed for sustained lunar surface activities that may follow the development of NASA’s new Orion crew vehicle and a Gateway structure that may orbit the Moon. In addition, robotic assets, like NASA’s Resource Prospector, are being developed to explore the nature and distribution of volatile deposits that might be suitable for scientific analysis and recovery. Based on the new results of Needham and Kring, those assets may be recovering ice that is partially composed of volatiles erupted from volcanic fissures over 3 billion years ago.
The new research was initiated from the LPI-Johnson Space Center’s (JSC) Center for Lunar Science and Exploration, led by Kring and supported by NASA’s Solar System Exploration Research Virtual Institute. Needham is a former postdoctoral researcher at the LPI. The LPI is operated for NASA by Universities Space Research Association (USRA).
For NASA’s Saturn explorer, the end will come all too quickly.
Cassini, NASA’s explorer of Saturn, remaining life is now measured in just a few days. Coming up on September 12, just three days before NASA’s veteran Saturn explorer takes a dive into the planet’s atmosphere, the spacecraft will whip around the hazy moon Titan in a slingshot maneuver that will seal its fate.
During these final days, Cassini will take one last look around. Onboard cameras will snap pictures of Titan and its hydrocarbon lakes, Saturn’s innermost rings, the bizarre hexagon-shaped jet stream at Saturn’s north pole, and other targets. On the evening of September 14, Cassini will send this last photo album to Earth, about 1.4 billion kilometers away, and the engineers at NASA’s Jet Propulsion Laboratory in Pasadena will post them online.
After that, no more pictures will be taken. But seven other instruments will continue to gather data on the chemical composition of Saturn’s atmosphere, its gravity and magnetic fields, its innermost radiation belts, and its rings—for as long as they can. “We’ll be transmitting the science data back almost as fast as we gather it,” says Tom Burk, Cassini’s attitude control team lead.
Scientists forecast rain storms of solid diamonds on two of the solar system’s most interesting planets
The obvious question any entrepreneur might ask is how do you mine these diamonds? In short, you don’t. It would take highly advanced space drones, the likes of which not even SpaceX is ready for yet, let alone the cost of getting there and back.
But that doesn’t make the idea of diamonds raining down on a distant planet any less of a spectacular discovery, igniting space-nerd radars everywhere.
According to the scientists who ran the experiment, the diamonds form in hydrocarbon-rich oceans of “slush” found around the solid cores of these two gad giants. According to the Washington Post,
Scientists have long speculated that the extreme pressures in this region might split those molecules into atoms of hydrogen and carbon, the latter of which then crystallize to form diamonds. These diamonds were thought to sink like rain through the ocean until they hit the solid core.
Cassini is the most sophisticated space probe ever built. Launched in 1997 as a joint NASA/European Space Agency mission, it took seven years to journey to Saturn. It’s been orbiting the sixth planet from the sun ever since, sending back data of immense scientific value and images of magnificent beauty.
Cassini now begins one last campaign. Dubbed the Grand Finale, it will end on Sept. 15, 2017 with the probe plunging into Saturn’s atmosphere, where it will burn up. Although Saturn was visited by three spacecraft in the 1970s and 1980s, my fellow scientists and I couldn’t have imagined what the Cassini space probe would discover during its sojourn at the ringed planet when it launched 20 years ago.
A planet of dynamic change
Massive storms periodically appear in Saturn’s cloud tops, known as Great White Spots, observable by Earthbound telescopes. Cassini has a front-row seat to these events. We have discovered that just like Earth’s thunderstorms, these storms contain lightning and hail.
Cassini has been orbiting Saturn long enough to observe seasonal changes that cause variations in its weather patterns, not unlike the seasons on Earth. Periodic storms often appear in late summer in Saturn’s northern hemisphere.
In 2010, during northern springtime, an unusually early and intense storm appeared in Saturn’s cloud tops. It was a storm of such immensity that it encircled the entire planet and lasted for almost a year. It was not until the storm ate its own tail that it eventually sputtered and faded. Studying storms such as this and comparing them to similar events on other planets (think Jupiter’s Great Red Spot) help scientists better understand weather patterns throughout the solar system, even here on Earth.
Cassini has also confirmed the existence of a bizarre hexagon-shaped polar vortex originally glimpsed by the Voyager mission in 1981. The vortex, a mass of whirling gas much like a hurricane, is larger than the Earth and has top wind speeds of 220 mph.
Home to dozens of diverse worlds
Cassini discovered that Saturn has 45 more moons than the 17 previously known – placing the total now at 62.
The largest, Titan, is bigger than the planet Mercury. It possesses a dense nitrogen-rich atmosphere with a surface pressure one and a half times that of Earth’s. Cassini was able to probe beneath this moon’s cloud cover, discovering rivers flowing into lakes and seas and being replenished by rain. But in this case, the liquid is not water, but rather liquid methane and ethane.
That’s not to say that water is not abundant there – but it’s so cold on Titan (with a surface temperature of -180℃) that water behaves like rock and sand. Although it has all the ingredients for life, Titan is essentially a “frozen Earth,” trapped at that moment in time before life could form.
The sixth-largest moon of Saturn, Enceladus, is an icy world about 300 miles in diameter. And for me, it’s the site of the Mission’s most spectacular finding.
The discovery started humbly, with a curious blip in magnetic field readings during the first flyby of Enceladus in 2004. As Cassini passed over the moon’s southern hemisphere, it detected strange fluctuations in Saturn’s magnetic field. From this, the Cassini magnetometer team inferred that Enceladus must be a source of ionized gas.
Intrigued, they instructed the Cassini navigators to make an even closer flyby in 2005. To our amazement, the two instruments designed to determine the composition of the gas that the spacecraft flies through, the Cassini Plasma Spectrometer (CAPS) and the Ion and Neutral Mass Spectrometer (INMS), determined that Cassini was unexpectedly passing through a cloud of ionized water. Emanating from cracks in the ice at Enceladus’ south pole, these water plumes gush into space at speeds up to 800 mph.
I am on the team that made the positive identification of water, and I have to say it was the most thrilling moment in my professional career. As far as Saturn’s moons were concerned, everyone thought all of the action would be at Titan. No one expected small, unassuming Enceladus to harbor any surprises.
Geologic activity happening in real time is quite rare in the solar system. Before Enceladus, the only known active world beyond Earth was Jupiter’s moon Io, which possesses erupting volcanoes. To find something akin to Old Faithful on a moon of Saturn was practically unimaginable. The fact that it all started with someone noticing an odd reading in the magnetic field data is a wonderful example of the serendipitous nature of discovery.
The story of Enceladus only becomes more extraordinary. In 2009, the plumes were directly imaged for the first time. We now know that water from Enceladus comprises the largest component of Saturn’s magnetosphere (the area of space controlled by Saturn’s magnetic field), and the plumes are responsible for the very existence of Saturn’s vast E-ring, the second outermost ring of the planet.
More amazingly, we now know that beneath the crust of Enceladus is a global ocean of liquid saltwater and organic molecules, all being heated by hydrothermal vents on the seafloor. Detailed analysis of the plumes show they contain hydrocarbons. All this points to the possibility that Enceladus is an ocean world harboring life, right here in our solar system.
When Cassini plunges into the cloud tops of Saturn later this year, it will mark the end of one of the most successful missions of discovery ever launched by humanity.
Scientists are now considering targeted missions to Titan, Enceladus or possibly both. One of the most valuable lessons one can take from Cassini is the need to continue exploring. As much as we learned from the first spacecraft to reach Saturn, nothing prepared us for what we would find with Cassini. Who knows what we will find next?
Ever since enthusiasm started growing over the possibility that there could be a ninth major planet orbiting the sun beyond Neptune, astronomers have been busy hunting it. One group is investigating four new moving objects found by members of the public to see if they are potential new solar system discoveries. As exciting as this is, researchers are also making discoveries that question the entire prospect of a ninth planet.
One such finding is our discovery of a minor planet in the outer solar system: 2013 SY99. This small, icy world has an orbit so distant that it takes 20,000 years for one long, looping passage. We found SY99 with the Canada-France-Hawaii Telescope as part of the Outer Solar System Origins Survey. SY99’s great distance means it travels very slowly across the sky. Our measurements of its motion show that its orbit is a very stretched ellipse, with the closest approach to the sun at 50 times that between the Earth and the sun (a distance of 50 “astronomical units”).
The new minor planet loops even further out than previously discovered dwarf planets such as Sedna and 2013 VP113. The long axis of its orbital ellipse is 730 astronomical units. Our observations with other telescopes show that SY99 is a small, reddish world, some 250 kilometres in diameter, or about the size of Wales in the UK.
SY99 is one of only seven known small icy worlds that orbit beyond Neptune at remarkable distances. How these “extreme trans-Neptunian objects” were placed on their orbits is uncertain: their distant paths are isolated in space. Their closest approach to the sun is so far beyond Neptune that they are thought to be “detached” from the strong gravitational influence of the giant planets in our solar system. But at their furthest points, they are still too close to be nudged around by the slow tides of the galaxy itself.
It’s been suggested that the extreme trans-Neptunian objects could be clustered in space by the gravitational influence of a “Planet Nine” that orbits much further out than Neptune. This planet’s gravity could lift out and detach their orbits – constantly changing their tilt. But this planet is far from proven.
In fact, its existence is based on the orbits of only six objects, which are very faint and hard to discover even with large telescopes. They are therefore prone to odd biases. It’s a bit like looking down into the deep ocean at a school of fish. The fish swimming near the surface are clearly visible. But the ones even only a meter down are fainter and murky, and take quite a lot of peering to be certain. The great bulk of the school, in the depths, is completely invisible. But the fish at the surface and their behaviour betray the existence of a whole school.
The biases mean SY99’s discovery can’t prove or disprove the existence of a Planet Nine. However, computer models do show that a Planet Nine would be an unfriendly neighbour to tiny worlds like SY99: its gravitational influence would starkly change its orbit – throwing it from the solar system entirely, or poking it into an orbit so highly inclined and distant that we wouldn’t be able to see it. SY99 would have to be one of an utterly vast throng of small worlds, continuously being sucked in and cast out by the planet.
The alternative explanation
But it turns out that there are other explanations. Our study based on computer modelling, accepted for publication in the Astronomical Journal, hint at the influence of an idea from everyday physics called diffusion. This is a very common type of behaviour in the natural world. Diffusion typically explains the random movement of a substance from a region of higher concentration to one of lower concentration – such as the way perfume drifts across a room.
We showed that a related form of diffusion can cause the orbits of minor planets to change from an ellipse that is initially only 730 astronomical units on its long axis to one that is as big as 2,000 astronomical units or bigger – and change it back again. In this process, the size of each orbit would vary by a random amount.
When SY99 comes to its closest approach every 20,000 years, Neptune will often be in a different part of its orbit on the opposite side of the solar system. But at encounters where both SY99 and Neptune are close, Neptune’s gravity will subtly nudge SY99, minutely changing its velocity. As SY99 travels out away from the sun, the shape of its next orbit will be different.
The long axis of SY99’s ellipse will alter, becoming either larger or smaller, in what physicists call a “random walk”. The orbit change takes place on truly astronomical time scales. It diffuses over the space of tens of millions of years. The long axis of SY99’s ellipse would change by hundreds of astronomical units over the 4.5 billion-year history of the solar system.
Several other extreme trans-Neptunian objects with smaller orbits also show diffusion, on a smaller scale. Where one goes, more can follow. It’s entirely plausible that the gradual effects of diffusion act on the tens of millions of tiny worlds orbiting in the near fringe of the Oort cloud (a shell of icy objects at the edge of the solar system). This gentle influence would slowly lead some of them to randomly shift their orbits closer to us, where we see them as extreme trans-Neptunian objects.
However, diffusion won’t explain the distant orbit of Sedna, which has its closest point too far out from Neptune for it to change its orbit’s shape. Perhaps Sedna gained its orbit from a passing star, aeons ago. But diffusion could certainly be bringing in extreme trans-Neptunian objects from the inner Oort cloud – without the need for a Planet Nine. To find out for sure, we’ll need to make more discoveries in this most distant region using our largest telescopes.
Ever since studies started suggesting that chemical reactions between water and rock on Saturn’s moon Enceladus could provide enough energy in the water to feed microbial life, scientists have been searching for proof that the right sort of reactions really do occur.
And during its last dive through the icy plumes that Enceladus erupts into space in October 2015, the Cassini spacecraft has finally managed to find it – in the form of molecular hydrogen. The finding, published in Science, means the moon can now be considered highly likely to be suitable to host microbial life. In fact, the results should undermine the last strong objection from those who argue it could not.
Enceladus is a small (502km in diameter) moon with an icy surface, a rocky interior and an ocean of liquid water sandwiched between the two. Cassini discovered back in 2005 that Enceladus is venting water into space, in the form of plumes of ice crystals escaping from cracks in the surface. For a decade, Enceladus was the only icy moon where this was known to happen, but plumes have recently been found on Europa, too, a larger icy moon of Jupiter.
Cassini’s discovery led to it being re-tasked to fly through Enceladus’s plumes. There, in addition to water, it was able to identify traces of methane, ammonia, carbon monoxide, carbon dioxide, simple organic molecules and salts.
Eventually, in March 2015, it detected microscopic particles of silica. By then, the composition of the plumes showed almost every sign that ocean water had reacted chemically with heated rock – altering the minerals of the rocky silicate seabed while the water became rich in chemicals.
Presumably, the ocean water is drawn into the rock, becomes heated, reacts chemically, and escapes back up to the ocean via “hydrothermal vents”. These exist on the floor of the Earth’s oceans, too, where the chemically charged water supports a rich ecology of microbes and other, more complex, life forms – requiring no sunlight.
The only missing evidence of water-rock chemical reactions in Enceladus was molecules of hydrogen, which should be released as a byproduct of the water-rock reactions. Searching for hydrogen was a key goal of Cassini’s final and closest dive through the plumes.
The new study unveils how hydrogen was detected during the frantic half-minute when Cassini was about 120km above the surface of Enceladus, whizzing through a plume at 8.5km per second. This was achieved by operating the mass spectrometer (an instrument which knocks electrons off chemical substances and sorts them based on their mass-to-charge ratio) in a special mode. It admitted plume material directly into the instrument’s detection chamber to avoid the possibility of hydrogen being generated by plume-water reacting with the metallic components of the instrument itself.
Hydrogen is of immense significance, because its presence along with hot water and rock would enable simple microbes to make a living. When dissolved carbon dioxide reacts with dissolved hydrogen, it produces methane and water. This chemical reaction releases energy that organisms can use to drive their metabolism. There are many kinds of “methanogenic” organisms at deep sea hydrothermal vents on Earth that do this. Now that we know Enceladus has all the necessary ingredients for this to happen, we are lacking only the proof of life itself.
For that we will need a purpose-built mission, such as the Enceladus Life Finder (ELF). This would collect and analyse any complex organic molecules in the plumes. It is hard to imagine a more important goal for solar system exploration than establishing whether a habitable environment, such as the warm bottom of Enceladus’s ocean, actually does host life.
Enceladus is a long way from Earth. If we were able to prove that it hosts life, it would be highly likely that such life had originated there, independently of life on Earth. That would be a crucial discovery. It would provide evidence to suggest that our galaxy is teeming with life, because if life began independently on two different bodies in our solar system, then surely it also got going on many of the potentially habitable planets that we are now finding around other stars.
Enceladus is a tiny world, and the amount of available energy and nutrients is small. Few scientists therefore expect it to host an ecosystem consisting of more than simple microbes. The much larger Europa, if it has life too, is a better prospect.
However, to protect Enceladus from the slightest risk of contamination by any terrestrial microbes that accidentally hitched a ride on Cassini, the craft will not be allowed to become a derelict object that might eventually crash onto its surface. Instead, the mission is facing its “grand finale”, a series of 22 orbits in which it will pass spectacularly between Saturn and its innermost ring. This will end with Cassini burning up in Saturn’s atmosphere.
Carbon is a building block of life on our planet. It is stored in reservoirs on Earth – in rocks, plants and soil – in the oceans, and in the atmosphere. And it cycles constantly between these reservoirs.
Understanding the carbon cycle is crucially important for many reasons. It provides us with energy, stored as fossil fuel. Carbon gases in the atmosphere help regulate Earth’s temperature and are essential to the growth of plants. Carbon passing from the atmosphere to the ocean supports photosynthesis of marine phytoplankton and the development of reefs. These processes and myriad others are all interwoven with Earth’s climate, but the manner in which the processes respond to variability and change in climate is not well-quantified.
Our research group at the University of Oklahoma is leading NASA’s latest Earth Venture Mission, the Geostationary Carbon Observatory, or GeoCarb. This mission will place an advanced payload on a satellite to study the Earth from more than 22,000 miles above the Earth’s equator. Observing changes in concentrations of three key carbon gases – carbon dioxide (CO2), methane (CH4) and carbon monoxide (CO) – from day to day and year to year will help us to make a major leap forward in understanding natural and human changes in the carbon cycle.
GeoCarb is also an innovative collaboration between NASA, a public university, a commercial technology development firm (Lockheed Martin Advanced Technology Center) and a commercial communications launch and hosting firm (SES). Our “hosted payload” approach will place a scientific observatory on a commercial communications satellite, paving the way for future low-cost, commercially enabled Earth observations.
Observing the carbon cycle
The famous “Keeling curve,” which tracks CO2 concentrations in Earth’s atmosphere, is based on daily measurements at Mauna Loa Observatory on Hawaii. It shows that global CO2 levels are rising over time, but also change seasonally due to biological processes. CO2 decreases during the Northern Hemisphere’s spring and summer months, as plants grow and take CO2 out of the air. It rises again in fall and winter when plants go relatively dormant and ecosystems “exhale” CO2.
A closer look shows that every year’s cycle is slightly different. In some years the biosphere takes more CO2 out of the atmosphere; in others it releases more to the atmosphere. We want to know more about what causes the year-to-year differences because that contains clues on how the carbon cycle works.
For example, during the El Niño of 1997-1998, a sharp rise in CO2 was largely driven by fires in Indonesia. The most recent El Niño in 2015-2016 also led to a rise in CO2, but the cause was probably a complex mixture of effects across the tropics – including reduced photosynthesis in Amazonia, temperature-driven soil release of CO2 in Africa and fires in tropical Asia.
These two examples of year-to-year variability in the carbon cycle, both globally and regionally, reflect what we now believe – namely, that variability is largely driven by terrestrial ecosystems. The ability to probe the climate-carbon interaction will require a much more quantitative understanding of the causes of this variability at the process level of various ecosystems.
Why study terrestrial emissions from space?
GeoCarb will be launched into geostationary orbit at roughly 85 degrees west longitude, where it will rotate in tandem with the Earth. From this vantage point, the major urban and industrial regions in the Americas from Saskatoon to Punta Arenas will be in view, as will the large agricultural areas and the expansive South American tropical forests and wetlands. Measurements of carbon dioxide, methane and carbon monoxide once or twice daily over much of the terrestrial Americas will help resolve flux variability for CO2 and CH4.
GeoCarb also will measure solar induced fluorescence (SIF) – plants emitting light that they cannot use back out into space. This “flashing” by the biosphere is strongly tied to the rate of photosynthesis, and so provides a measure of how much CO2 plants take in.
NASA pioneered the technology that GeoCarb will carry on an earlier mission, the Orbiting Carbon Observatory 2 (OCO-2). OCO-2 launched into a low Earth orbit in 2014 and has been measuring CO2 from space ever since, passing from pole to pole several times per day as the Earth turns beneath it.
Though the instruments are similar, the difference in orbit is crucial. OCO-2 samples a narrow 10-km track over much of the globe on a 16-day repeat cycle, while GeoCarb will look at the terrestrial Western Hemisphere continuously from a fixed position, scanning most of this land mass at least once per day.
Where OCO-2 may miss observing the Amazon for a season due to regular cloud cover, GeoCarb will target the cloud-free regions every day with flexible scanning patterns. Daily revisits will show the biosphere changing in near-real time alongside weather satellites such as GOES 16, which is located at 105 degrees west, helping to connect the dots between the components of Earth’s system.
Nuances of the carbon cycle
Many processes affect levels of CO2 in the atmosphere, including plant growth and decay, fossil fuel combustion and land use changes, such as clearing forests for farming or development. Attributing atmospheric CO2 changes to different processes is difficult using CO2 measurements alone, because the atmosphere mixes CO2 from all of the different sources together.
As mentioned earlier, in addition to CO2 and CH4, GeoCarb will measure CO. Burning fossil fuel releases both CO and CO2. This means that when we see high concentrations of both gases together, we have evidence that they are being released by human activities.
Making this distinction is key so we do not assume that human-induced CO2 emissions come from a decrease in plant activity or a natural release of CO2 from soil. If we can distinguish between man-made and natural emissions, we can draw more robust conclusions about the carbon cycle. Knowing what fraction of these changes is caused by human activities is important for understanding our impact on the planet, and observing and measuring it is essential to any conversation about strategies for reducing CO2 emissions.
GeoCarb’s measurement of methane will be a crucial element in understanding the global carbon-climate system. Methane is produced by natural systems, such as wetlands, and by human activities such as natural gas production. We do not understand the methane portion of the carbon cycle as well as CO2. But just as with CO2, methane observations tell us a lot about the functioning of natural systems. Marshes release methane as part of the natural decay in the system. The rate of release is tied to how wet/dry and warm/cool the system is.
It is uncertain how much natural gas production contributes to methane emissions. One reason to quantify these emissions more accurately is that they represent lost revenue for energy producers. The Environmental Protection Agency estimates a U.S. leakage rate of around 2 percent, which could add up to billions of dollars annually.
We expect based on simulations that GeoCarb will produce maps that highlight the largest leaks with only a few days of observations. Finding leaks will reduce costs for energy producers and reduce the carbon footprint of natural gas. Currently, energy companies find leaks by sending personnel with detection equipment to suspected leak sites. Newer airborne sensors could make the process cheaper, but they are still deployed on a limited basis and in an ad hoc manner. GeoCarb’s regular observations will provide leakage information to producers in a timely manner to help them limit their losses.
Watching the planet breathe
With daily scans of landmasses in the Western Hemisphere, GeoCarb will provide an unprecedented number of high-quality measurements of CO2, CH4 and CO in the atmosphere. These observations, along with direct measurements of photosynthetic activity from SIF observations, will raise our understanding of the carbon cycle to a new level.
For the first time we will be able to watch as the Western Hemisphere breathes in and out every day, and to see the seasons change through the eyes of the biosphere. Equipped with these observations, we will begin to disentangle natural and human contributions to the carbon balance. These insights will help scientists make robust predictions about Earth’s future.
They are both found in the Afar Region of Ethiopia and are part of the East African Rift System – an active tectonic plate boundary that’s splitting apart plates at a rate of 7 mm per year. The combination of this area’s geology and environment make it a uniquely extreme place to do research. In collaboration with the Europlanet research team, I am investigating the geological and biological aspects of the Danakil Depression.
Our aim is to study microbes, specifically extremophiles – organisms that thrive in extreme environments. They can live in hot springs, acidic fields, salty lakes and polar ice caps – conditions that would kill humans, animals, and plants. Their existence suggests that life can develop mechanisms to withstand physical and chemical conditions like those on the planet Mars.
There’s no other natural environment like it. What we have found at the site is a combination of extreme physico-chemical parameters. Toxic gases saturate the air, the pH is extremely acidic and saline and metal concentrations are very high.
In these extreme ecosystems we expect to find microbial life in the form of extremophiles, polyextremophiles and potentially new forms of polyextremophiles – these are extremophilic organisms that can tolerate, or adapt, to a combination of physico-chemical parameters.
This harsh environment was created by the splitting apart of the old African Plate into two plates – the Somali and Nubian Plates. In millions of years, these two plates will be definitively separated and a new ocean basin will form.
Much of the 40km by 10 km Danakil Depression lies between 150-100m below sea level. It’s therefore one of the lowest land areas on Earth. The Dallol volcano, in the northern part of the Danakil Depression, was formed in 1926 by a phreatic eruption. This is when groundwater is heated by magma – essentially, a steam eruption without the lava ejection. Dallol has an elevation of approximately 50m below sea level.
The Depression is known as the hottest place on Earth. It’s classified as a hyperarid climatic zone and is consistently hot throughout the year. In the Dallol, because of the area’s geothermal activity, the average daily temperature is 45°C. I have registered a temperature there of 55°C – when I had to stop working! The region’s precipitation ranges is very low with an average annual rainfall of only 100-200 mm. In the dry areas of South Africa there would be an average annual rainfall of at least 464mm.
Geothermally heated groundwater rises from the Earth’s crust to the surface, accumulating in the Dallol crater. This creates spectacular and colourful hot springs that are extremely acidic and salty. The area is also characterised by toxic sulphur and chlorine vapours as a result of natural degassing volcanic processes.
What can survive
Living organisms tend to be sensitive to drastic changes in their environments. The cells that make them up can be seriously compromised in extreme physical (relating to temperature, desiccation, radiation, and pressure) and (geo)chemical (such as salinity, pH or heavy metals) conditions.
So what could survive in the Danakil’s harsh environment?
After a detailed study of the area, we have determined that there’s DNA evidence of microbial life. Life that, because of the similar extreme salty environment with volcanic origin, could be what’s surviving on Mars.
The microorganisms able to survive such extreme conditions must be a group of prokaryotes. All living things consist of two cell types: prokaryotes and eukaryotes. Organisms whose cells lack a nucleus and have DNA floating loosely in the liquid centre of the cell are prokaryotes. These are the most common and most ancient forms of life on earth.
What these microorganisms need is liquid water, metabolically suitable carbon, energy, and nutrient sources.
Barbara Cavalazzi, Professor in Geobiology and Astrobiology at the Biological, Geological, and Environmental Sciences-BiGeA of the University of Bologna, Italy, and visiting lecturer at University of Johannesburg, South Africa., University of Bologna