For several months, scientists have been keeping an eye on a piece of Antarctica’s Larsen C ice shelf, waiting for the inevitable. And now it has happened.
Sometime between July 10 and July 12, 2017 a trillion ton iceberg split off, “changing the outline of the Antarctic Peninsula forever,” said one scientist.
The new iceberg is now called A68, and at 2,240 square miles (5,800 square km) it is one of the biggest ever recorded, about the size of Delaware in the US, or twice the size of Luxembourg.
A fissure on the ice shelf first appeared several years ago, but seemed relatively stable until January 2016, when it began to lengthen. In January 2017 alone, the crack grew by 20 km, reaching a total length of about 175 km.
The calving of the iceberg was confirmed by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite and was reported this morning by Project MIDAS, an Antarctic research project based in the UK.
The MODIS instrument on NASA’s Aqua satellite also confirmed the complete separation of the iceberg.
Larsen C is a floating platform of glacial ice on the east side of the Antarctic Peninsula, is the fourth largest ice shelf ringing Earth’s southernmost continent. With the break-off of this iceberg, the Larsen C shelf area has shrunk by approximately 10 percent.
Some scientists say the Larsen C rift and iceberg calving is not a warning of imminent sea level rise, and linking climate change to this specific event is complicated. Adrian Luckman, Professor of Glaciology and Remote Sensing from Swansea University wrote a detailed explanation of this for The Conversation.
David Vaughan, glaciologist and Director of Science at British Antarctic Survey (BAS), said, “Larsen C itself might be a result of climate change, but, in other ice shelves we see cracks forming, which we don’t believe have any connection to climate change. For instance on the Brunt Ice Shelf where BAS has its Halley Station, there those cracks are a very different kind which we don’t believe have any connection to climate change.”
While Vaughan said they see no obvious signal that climate warming is causing the whole of Antarctica to break up, he added that there is little doubt that climate change is causing ice shelves to disappear in some parts of Antarctica at the moment.
“Around the Antarctic Peninsula, where we saw several decades of warming through the latter half of the 20th century, we have seen these ice shelves collapsing and ice loss increasing,” he said. “There are other parts of the Antarctica that which are losing ice to the oceans but those are affected less by atmospheric warming and more by ocean change.
Scientists said the loss of such a large piece is of interest because ice shelves along the peninsula play an important role in ‘buttressing’ glaciers that feed ice seaward, effectively slowing their flow.
“The interesting thing is what happens next, how the remaining ice shelf responds,” said Kelly Brunt, a glaciologist with NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland in College Park. “Will the ice shelf weaken? Or possibly collapse, like its neighbors Larsen A and B? Will the glaciers behind the ice shelf accelerate and have a direct contribution to sea level rise? Or is this just a normal calving event?”
The U.S. National Ice Center will monitor the trajectory of the new iceberg, but they don’t expect it to travel far very fast, and it shouldn’t cause any immediate problems for navigation of ships.
Scientists have known for some time that the Earth goes through cycles of climatic change. Owing to changes in Earth’s orbit, geological factors, and/or changes in Solar output, Earth occasionally experiences significant reductions in its surface and atmospheric temperatures. This results in long-term periods of glaciation, or what is more colloquially known as an “ice age”.
These periods are characterized by the growth and expansion of ice sheets across the Earth’s surface, which occurs every few million years. By definition we are still in the last great ice age – which began during the late Pliocene epoch (ca. 2.58 million years ago) – and are currently in an interglacial period, characterized by the retreat of glaciers.
While the term “ice age” is sometime used liberally to refer to cold periods in Earth’s history, this tends to belie the complexity of glacial periods. The most accurate definition would be that ice ages are periods when ice sheets and glaciers expand across the planet, which correspond to significant drops in global temperatures and can last for millions of years.
During an ice age, there are significant temperature differences between the equator and the poles, and temperatures at deep-sea levels have also been shown to drop. This allows for large glaciers (comparable to continents) to expand, covering much of the surface area of the planet. Since the Pre-Cambrian Era (ca. 600 million years ago), ice ages have occurred at widely space intervals about about 200 million years.
History of Study:
The first scientist to theorize about past glacial periods was the 18th century Swiss engineer and geographer Pierre Martel. In 1742, while visiting an Alpine valley, he wrote about the dispersal of large rocks in erratic formations, which the locals attributed to the glaciers having once extended much further. Similar explanations began to emerge in the ensuing decades for similar patterns of boulder distribution in other parts of he world.
From the middle of the 18th century onward, European scholars increasingly began to contemplate ice as a means of transporting rocky material. This included the presence of boulders in coastal areas in the Baltic states and the Scandinavian peninsula. However, it was Danish-Norwegian geologist Jens Esmark (1762–1839) who first argued the existence of a sequence of world wide ice ages.
This theory was detailed in a paper he published in 1824, in which he proposed that changes in Earth’s climate (which were due to changes in its orbit) were responsible. This was followed in 1832 by German geologist and forestry professor Albrecht Reinhard Bernhardi speculating about how the polar ice caps may have once reached as far as the temperate zones of the world.
At this same time, German botanist Karl Friedrich Schimper and Swiss-American biologist Louis Agassiz began independently developing their own theory about global glaciation, which led toSchimper coining the term “ice age” in 1837. By the late 19th century, ice age theory gradually began to gain widespread acceptance over the notion that the Earth cooled gradually from its original, molten state.
By the 20th century, Serbian polymath Milutin Milankovic developed his concept of Milankovic cycles, which linked long-term climate changes to periodic changes in the Earth’s orbit around the Sun. This offered a demonstrable explanation for ice ages, and allowed scientists to make predictions about when significant changes in Earth’s climate might occur again.
Evidence for Ice Ages:
There are three forms of evidence for ice age theory, which range from the geological and the chemical to the paleontological (i.e. the fossil record). Each has its particular benefits and drawbacks, and has helped scientists to develop a general understanding of the effect ice ages have had on geological record for the past few billion years.
Geological: Geological evidence includes rock scouring and scratching, carved valleys, the formation of peculiar types of ridges, and the deposition of unconsolidated material (moraines) and large rocks in erratic formations. While this sort of evidence is what led to ice age theory in the first place, it remains temperamental.
For one, successive glaciation periods have different effects on a region, which tends to distort or erase geological evidence over time. In addition, geological evidence is difficult to date exactly, causing problems when it comes to getting an accurate assessment of how long glacial and interglacial periods have lasted.
Chemical: This consists largely of variations in the ratios of isotopes in fossils discovered in sediment and rock samples. For more recent glacial periods, ice cores are used to construct a global temperature record, largely from the presence of heavier isotopes (which lead to higher evaporation temperatures). They often contain bubbles of air as well, which are examined to assess the composition of the atmosphere at the time.
Limitations arise from various factors, however. Foremost among these are isotope ratios, which can have a confounding effect on accurate dating. But as far as the most recent glacial and interglacial periods are concerned (i.e. during the past few million years), ice core and ocean sediment core samples remain the most trusted form of evidence.
Paleontological: This evidence consists of changes in the geographical distribution of fossils. Basically, organisms that thrive in warmer conditions become extinct during glacial periods (or become highly restricted in lower latitudes), while cold-adapted organisms thrive in these same latitudes. Ergo, reduced amounts of fossils in higher latitudes is an indication of the spread of glacial ice sheets.
This evidence can also be difficult to interpret because it requires that the fossils be relevant to the geological period under study. It also requires that sediments over wide ranges of latitudes and long periods of time show a distinct correlation (due to changes in the Earth’s crust over time). In addition, there are many ancient organisms that have shown the ability to survive changes in conditions for millions of years.
As a result, scientists rely on a combined approach and multiple lines of evidence wherever possible.
Causes of Ice Ages:
The scientific consensus is that several factors contribute to the onset of ice ages. These include changes in Earth’s orbit around the Sun, the motion of tectonic plates, variations in Solar output, changes in atmospheric composition, volcanic activity, and even the impact of large meteorites. Many of these are interrelated, and the exact role that each play is subject to debate.
Earth’s Orbit: Essentially, Earth’s orbit around the Sun is subject to cyclic variations over time, a phenomenon also known as Milankovic (or Milankovitch) cycles. These are characterized by changing distances from the Sun, the precession of the Earth’s axis, and the changing tilt of the Earth’s axis – all of which result in a redistribution of the sunlight received by the Earth.
The most compelling evidence for Milankovic orbital forcing corresponds closely to the most recent (and studied) period in Earth’s history (circa. during the last 400,000 years). During this period, the timing of glacial and interglacial periods are so close to changes in Milankovic orbital forcing periods that it is the most widely accepted explanation for the last ice age.
Tectonic Plates: The geological record shows an apparent correlation between the onset of ice ages and the positions of the Earth’s continents. During these periods, they were in positions which disrupted or blocked the flow of warm water to the poles, thus allowing ice sheets to form.
This in turn increased the Earth’s albedo, which reduces the amount of solar energy absorbed by the Earth’s atmosphere and crust. This resulted in a positive feedback loop, where the advance of ice sheets further increased the Earth’s albedo and allowed for more cooling and more glaciation. This would continue until the onset of a greenhouse effect ended the period of glaciation.
Based on past ice-ages, three configurations have been identified that could lead to an ice age – a continent sitting atop the Earth’s pole (as Antarctica does today); a polar sea being land-locked (as the Arctic Ocean is today); and a super continent covering most of the equator (as Rodinia did during the Cryogenian period).
In addition, some scientists believe that the Himalayan mountain chain – which formed 70 million years ago – has played a major role in the most recent ice age. By increasing the Earth’s total rainfall, it has also increased the rate at which CO² has been removed from the atmosphere (thereby decreasing the greenhouse effect). Its existence has also paralleled the long-term decrease in Earth’s average temperature over the past 40 million years.
Atmospheric Composition: There is evidence that levels of greenhouse gases fall with the advance of ice sheets and rise with their retreat. According to the “Snowball Earth” hypothesis – in which ice completely or very nearly covered the planet at least once in the past – the ice age of the late Proterozoic was ended by an increase in CO² levels in the atmosphere, which was attributed to volcanic eruptions.
However, there are those who suggest that increased levels of carbon dioxide may have served as a feedback mechanism, rather than the cause. For example, in 2009, an international team of scientists produced a study – titled “The Last Glacial Maximum” – that indicated that an increase in solar irradiance (i.e. energy absorbed from the Sun) provided the initial change, whereas greenhouse gases accounted for the magnitude of change.
Major Ice Ages:
Scientists have determined that at least five major ice ages took place in Earth’s history. These include the Huronian, Cryogenian, Andean-Saharan, Karoo, and the Qauternary ice ages. The Huronian Ice Age is dated to the early Protzerozoic Eon, roughly 2.4 to 2.1 billion years ago, based on geological evidence observed to the north and north-east of Lake Huron (and correlated to deposits found in Michigan and Western Australia).
The Cryogenian Ice Age lasted from roughly 850 to 630 million years ago, and was perhaps the most severe in Earth’s history. It is believed that during this period, the glacial ice sheets reached the equator, thus leading to a “Snowball Earth” scenario. It is also believed that ended due to a sudden increase in volcanic activity that triggered a greenhouse effect, though (as noted) this is subject to debate.
The Andean-Saharan Ice Age occurred during the Late Ordovician and the Silurian period (roughly 460 to 420 million years ago). As the name suggests, the evidence here is based on geological samples take from the Tassili n’Ajjer mountain range in the western Sahara, and correlated by evidence obtained from the Andean mountain chain in South America (as well as the Arabian peninsula and the south Amazon basin).
The Karoo Ice Age is attributed to the evolution of land plants during the onset of the Devonian period (ca. 360 to 260 million years ago) which caused a long-term increase in planetary oxygen levels and a reduction in CO² levels – leading to global cooling. It is named after sedimentary deposits that were discovered in the Karoo region of South Africa, with correlating evidence found in Argentina.
The current ice age, known as the Pliocene-Quaternary glaciation, started about 2.58 million years ago during the late Pliocene, when the spread of ice sheets in the Northern Hemisphere began. Since then, the world has experienced several glacial and interglacial periods, where ice sheets advance and retreat on time scales of 40,000 to 100,000 years.
The Earth is currently in an interglacial period, and the last glacial period ended about 10,000 years ago. What remains of the continental ice sheets that once stretched across the globe are now restricted to Greenland and Antarctic, as well as smaller glaciers – like the one that covers Baffin Island.
Anthropogenic Climate Change:
The exact role played by all the mechanisms that ice ages are attributed to – i.e. orbital forcing, solar forcing, geological and volcanic activity – are not yet entirely understood. However, given the role of carbon dioxide and other greenhouse gas emissions, there has been a great deal of concern in recent decades what long-term effects human activity will have on the planet.
For instance, in at least two major ice ages, the Cryogenian and Karoo Ice Ages, increases and decreases in atmospheric greenhouse gases are believed to have played a major role. In all other cases, where orbital forcing is believed to be the primary cause of an ice age ending, increased greenhouse gas emissions were still responsible for the negative feedback that led to even greater increases in temperature.
The addition of CO2 by human activity has also played a direct role in climatic changes taking place around the world. Currently, the burning of fossil fuels by humans constitutes the largest source of emissions of carbon dioxide (about 90%) worldwide, which is one of the main greenhouse gases that allows radiative forcing (aka. the Greenhouse Effect) to take place.
In 2013, the National Oceanic and Atmospheric Administration announced that CO² levels in the upper atmosphere reached 400 parts per million (ppm) for the first time since measurements began in the 19th century. Based on the current rate at which emissions are growing, NASA estimates that carbon levels could reach between 550 to 800 ppm in the coming century.
If the former scenario is the case, NASA anticipates a rise of 2.5 °C (4.5 °F) in average global temperatures, which would be sustainable. However, should the latter scenario prove to be the case, global temperatures will rise by an average of 4.5 °C (8 °F), which would make life untenable for many parts of the planet. For this reason, alternatives are being sought out for development and widespread commercial adoption.
What’s more, according to a 2012 research study published in Nature Geoscience – titled “Determining the natural length of the current interglacial” – human emissions of CO² are also expected to defer the next ice age. Using data on Earth’s orbit to calculate the length of interglacial periods, the research team concluded that the next ice (expected in 1500 years) would require atmospheric CO² levels to remain beneath around 240?ppm.
Learning more about the longer ice ages as well the shorter glacial periods that have taken place in Earth’s past is important step towards understanding how Earth’s climate changes over time. This is especially important as scientists seek to determine how much of modern climate change is man-made, and what possible counter-measures can be developed.
A reprieve from Global Warming? A hiatus? That would be nice, wouldn’t it? But in this case, a hiatus is not quite what it seems.
Everybody knows that global warming is partly caused by human activities, largely our use of fossil fuels. We understand how it works and we fear for the future. But there’s been a slowdown in the global mean surface temperature increase between 1998 to 2013. We haven’t lowered our emissions of greenhouse gases (GHGs) significantly during that time, so what happened?
A new multi-institutional study involving NASA’s Jet Propulsion Laboratory (JPL), the National Oceanographic and Atmospheric Institute, and others, concludes that Earth’s oceans have absorbed the heat. So instead of the global mean surface temperature rising at a steady rate, the oceans have taken on the job as global heat sink. But what’s the significance of this?
“The hiatus period gives scientists an opportunity to understand uncertainties in how climate systems are measured, as well as to fill in the gap in what scientists know.” -Xiao-Hai Yan, University of Delaware, Newark
In terms of the on-going rise in the temperature of the globe, the hiatus is not that significant. But in terms of the science of global warming, and how well we understand it, the hiatus gives scientists an opportunity.
The new paper, titled “The Global Warming Hiatus: Slowdown or Redistribution?” grew out of the U.S. Climate Variability and Predictability Program (CLIVAR) panel session at the 2015 American Geophysical Union fall meeting. From those discussions, scientists reached consensus on three key points:
From 1998 to 2013, the rate of global mean surface warming slowed, which some call the “global warming hiatus.”
Natural variability plays a large role in the rate of global mean surface warming on decadal time scales.
Improved understanding of how the ocean distributes and redistributes heat will help the scientific community better monitor Earth’s energy budget. Earth’s energy budget is a complex calculation of how much energy enters our climate system from the sun and what happens to it: how much is stored by the land, ocean or atmosphere.
The paper is a reminder that climate science is complex, and that the oceans play a big part in global warming. As Yan says, “To better monitor Earth’s energy budget and its consequences, the ocean is most important to consider because the amount of heat it can store is extremely large when compared to the land or atmospheric capacity.”
“…”arguably, ocean heat content — from the surface to the seafloor — might be a more appropriate measure of how much our planet is warming.” – from the paper “The Global Warming Hiatus: Slowdown or Redistribution?”
The team behind this new research suggests that saying there’s been a hiatus in global warming is confusing. They suggest “global warming hiatus” be replaced with “global surface warming slowdown.”
There’s a danger in calling it a “global warming hiatus.” Those opposed to climate change and who think it’s a hoax can use that term to discredit climate science. They’ll claim that the “hiatus” shows we don’t understand climate change and the Earth may have stopped warming. But in any case, it’s the long-term trend—change over the course of a century or more—that defines “global warming,” not the change from year to year or even decade to decade.
There’s much more to learn about the oceans’ role in global warming. Research shows that some ocean areas absorb heat much faster than others. But whatever the fine detail of it is, there is broad agreement in the scientific community that the global surface warming slowdown was caused by an increased uptake of heat energy by the world’s oceans.
NASA uses a lot of tools to monitor the Earth’s temperature. For an interesting look at the Earth’s vital signs, check out Nasa’s Eyes. This easy to use visualization tool lets you take a closer look at the Earth’s temperature, CO2 levels, soil moisture levels, sea levels, and other things.
It’s long been humanity’s dream to do something useful with our smartphones. Sure, we can take selfies, and post pictures of our meals, but true smartphone greatness has eluded us. Until now, that is.
Thanks to NASA, we can now do some citizen science with our ubiquitous devices.
For over 20 years, and in schools in over 110 countries, NASA’s Global Learning and Observations to Benefit the Environment (GLOBE) program has helped students understand their local environment in a global context. Now NASA has released the GLOBE Observer app, which allows users to capture images of clouds in their local environment, and share them with scientists studying the Earth’s climate.
“With the launch of GLOBE Observer, the GLOBE program is expanding beyond the classroom to invite everyone to become a citizen Earth scientist,” said Holli Riebeek Kohl, NASA lead of GLOBE Observer. The app will initially be used to capture cloud observations and images because they’re such an important part of the global climate system. But eventually, GLOBE Observer will also be used to observe land cover, and to identify types of mosquito larvae.
GLOBE has two purposes. One is to collect solid scientific data, the other is to increase users’ awareness of their own environments. “Once you collect environmental observations with the app, they are sent to the GLOBE data and information system for use by scientists and students studying the Earth,” said Kohl. “You can also use these observations for your own investigations and interact with a vibrant community of individuals from around the world who care about Earth system science and our global environment.”
Clouds are a dynamic part of the Earth’s climate system. Depending on their type, their altitude, and even the size of their water droplets, they either trap heat in the atmosphere, or reflect sunlight back into space. We have satellites to observe and study clouds, but they have their limitations. An army of citizen scientists observing their local cloud population will add a lot to the efforts of the satellites.
“Clouds are one of the most important factors in understanding how climate is changing now and how it’s going to change in the future,” Kohl said. “NASA studies clouds from satellites that provide either a top view or a vertical slice of the clouds. The ground-up view from citizen scientists is valuable in validating and understanding the satellite observations. It also provides a more complete picture of clouds around the world.”
The GLOBE team has issued a challenge to any interested citizen scientists who want to use the app. Over the next two weeks, the team is hoping that users will make ground observations of clouds at the same time as a cloud-observing satellite passes overhead. “We really encourage all citizen scientists to look up in the sky and take observations while the satellites are passing over through Sept. 14,” said Kohl.
The app makes this easy to do. It informs users when a satellite will be passing overhead, so we can do a quick observation at that time. We can also use Facebook or Twitter to view daily maps of the satellite’s path.
“Ground measurements are critical to validate measurements taken from space through remote sensing,” said Erika Podest, an Earth scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who is working with GLOBE data. “There are some places in the world where we have no ground data, so citizen scientists can greatly contribute to advancing our knowledge this important part of the Earth system.”
The app itself seems pretty straightforward. I checked for upcoming satellite flyovers and was notified of 6 flyovers that day. It’s pretty quick and easy to step outside and take an observation at one of those times.
I did a quick observation from the street in front of my house and it took about 2 minutes. To identify cloud types, you just match what you see with in-app photos of the different types of clouds. Then you estimate the percentage of cloud cover, or specify if the sky is obscured by blowing snow, or fog, or something else. You can also add pictures, and the app guides you in aiming the camera properly.
The GLOBE Observer app is easy to use, and kind of fun. It’s simple enough to fit a quick cloud observation in between selfies and meal pictures.
NEW JERSEY – Record breaking snow from the ‘Blizzard of 2015’ hit vast regions of the US Northeast today, Jan. 27, 2015, stretching from Long Island to New England.
NASA and NOAA Earth orbiting satellites are keeping track of the storm affecting millions of residents.
This afternoon the agencies provided a new set of night-time and daytime views of the Blizzard of 2015 taken by the Suomi NPP and the GOES-East satellites.
The crippling blizzard is causing misery, extensive destruction to homes and businesses in localized areas, power outages, traffic accidents, breaks in some sea walls and deaths.
The satellite image above shows a combination of the day-night band and high resolution infrared imagery from the NASA-NOAA’s Suomi NPP satellite.
It was taken as the historic blizzard neared peak intensity as it moved over the New York area and through the Boston Metropolitan areas at 06:45Z (1:45 a.m. EST) on January 27, 2015.
The high cloud tops from the most intense parts of the storm blurred the regions normally bright nighttime lights in the satellite image.
Although the snow totals were about half the over two feet forecast for the New York Metropolitan region, many areas to the north and east were inundated with very heavy to historic snow fall totals, as bad or worse than the forecasters predicted.
Over two feet of snow fell on areas of New York’s Long Island and stretching north to vast regions of Connecticut, Massachusetts, New Hampshire and into Maine.
Near hurricane force waves are crashing into some coastal towns along the Massachusetts shoreline. Wind gusts as high as 78 mph have been recorded.
“Highest snowfall report has been Auburn, MA with 32.5 inches! Wind gust reports as high as 78 mph in Nantucket, MA,” according to a tweet this evening from the National Weather Service (NWS).
Worchester, Mass had a record breaking 31 inches of snow. And it’s still falling this evening in the 2nd largest city in New England.
A flood emergency is in effect in Marshfield, Mass., where an 80 foot section of the seawall was smashed by crashing waves and is destroying homes as shown on NBC Nightly News.
Blinding snow is raging in Portland, Maine this evening according on a live NBC News report.
“At 10 a.m. EST, the National Weather Service noted “the powerful nor’easter that brought moderate to heavy snowfall and blizzard conditions to the Northeast on Monday will continue to affect the region on Tuesday, with heavy snow and blizzard conditions expected from eastern Long Island to Maine as the system slowly moves to the northeast. Snow and strong winds will being tapering off from south to north Tuesday night into Wednesday morning,” wrote NASA’s Rob Gutro of NASA’s Goddard Space Flight Center in an update.
“Later on January 27, 2015 at 17:35 UTC (12:35 p.m. EST) NOAA’s Geostationary Operational Environmental or GOES-East satellite captured an image of the nor’easter over New England. The image was created by the NASA/NOAA GOES Project and showed the clouds associated with the nor’easter blanketing New England. An occluded front extended north and eastward out of the low pressure area’s center out into the Atlantic Ocean.”
The latest NOAA forecast as of 4 PM, Jan. 27 states:
HIGH WINDS AND HEAVY SNOW WILL BEGIN TO GRADUALLY TAPER OFF FROM SOUTH TO NORTH TONIGHT…BUT WILL LAST INTO EARLY WEDNESDAY MORNING ACROSS PORTIONS OF MAINE. HEAVY SNOWFALL WILL COMBINE WITH SUSTAINED WINDS OF 30 TO 40 MPH…AND GUSTS IN EXCESS OF 50 MPH…TO CREATE LIFE-THREATENING WHITEOUT OR BLIZZARD CONDITIONS. THESE WINDS MAY LEAD TO DOWNED TREES AND POWER LINES RESULTING IN POWER OUTAGES. TRAVEL WILL BE IMPOSSIBLE AND LIFE-THREATENING IN MANY AREAS. ALONG THE IMMEDIATE COASTLINE…WIND GUSTS TO NEAR 65 MPH WILL BE POSSIBLE. COASTAL FLOODING AND SEVERE BEACH EROSION WILL ALSO BE A POSSIBILITY…AND VULNERABLE ROADS AND STRUCTURES MAY BE FLOODED OR DAMAGED.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Venus really sucks. It’s as hot as an oven with a dense, poisonous atmosphere. But how did it get that way?
Venus sucks. Seriously, it’s the worst. The global temperature is as hot as an oven, the atmospheric pressure is 90 times Earth, and it rains sulfuric acid. Every part of the surface of Venus would kill you dead in moments.
Let’s push Venus into the Sun and be done with that terrible place. Its proximity is lowering our real estate values and who knows what sort of interstellar monstrosities are going to set up shop there, and be constantly knocking on our door to borrow the mower, or a cup or sugar, or sneak into our yard at night and eat all our dolphins.
You might argue that Venus is worth saving because it’s located within the Solar System’s habitable zone, that special place where water could exist in a liquid state on the surface. But we’re pretty sure it doesn’t have any liquid water. Venus may have been better in the past, clearly it started hanging out with wrong crowd, taking a bad turn down a dark road leading it to its current state of disrepair.
Could Venus have been better in the past? And how did it go so wrong? In many ways, Venus is a twin of the Earth. It’s almost the same size and mass as the Earth, and it’s made up of roughly the same elements. And if you stood on the surface of Venus, in the brief moments before you evacuated your bowels and died horribly, you’d notice the gravity feels pretty similar.
In the ancient past, the Sun was dimmer and cooler than it is now. Cool enough that Venus was much more similar to Earth with rivers, lakes and oceans. NASA’s Pioneer spacecraft probed beneath the planet’s thick clouds and revealed that there was once liquid water on the surface of Venus. And with liquid water, there could have been life on the surface and in those oceans.
Here’s where Venus went wrong. It’s about a third closer to the Sun than Earth, and gets roughly double the solar radiation. The Sun has been slowly heating up over the millions and billions of years. At some point, the planet reached a tipping point, where the water on the surface of Venus completely evaporated into the atmosphere.
Water vapor is a powerful greenhouse gas, and this only increased the global temperature, creating a runaway greenhouse effect on Venus. The ultraviolet light from the Sun split apart the water vapor into oxygen and hydrogen. The hydrogen was light enough to escape the atmosphere of Venus into space, while the oxygen recombined with carbon to form the thick carbon dioxide atmosphere we see today. Without that hydrogen, Venus’ water is never coming back.
Are you worried about our changing climate doing that here? Don’t panic. The amount of carbon dioxide released into the atmosphere of Venus is incomprehensible. According to the IPCC, the folks studying global warming, human activities have no chance of unleashing runaway global warming. We’ll just have the regular old, really awful global warming. So, it’s okay to panic a bit, but do it in the productive way that results in your driving your car less.
The Sun is still slowly heating up. And in a billion years or so, temperatures here will get hot enough to boil the oceans away. And then, Earth and Venus will be twins again and then we can push them both into the Sun.
I know, I said the words “climate change”. Feel free to have an argument in the comments below, but play nice and bring science.
Predicting the weather here on Earth is never an easy thing, but predicting it on Mars may be ever trickier. Such is the argument presented by a recent study concerning “macroweather” patterns on the Red Planet, a new regime for understanding how planetary environments work.
When it comes to describing the climate of a planet, two important concepts come into play. First, there’s weather, which covers day-to-day changes due to fluctuations in the atmosphere. Second, there’s climate, which is more stable and subject to change over the course of decades. Macroweather, the latest addition to the game, describes the relatively stable periods that exist between short-term weather and long-term climate.
For those of us dwelling here on planet Earth, these are familiar concepts. But researchers say this same three-part pattern applies to atmospheric conditions on Mars. The results of a new paper, published today in Geophysical Research Letters also show that the Sun plays a major role in determining macroweather.
The scientists chose to study Mars because of the wealth of data it has provided in recent decades, which they then used to test their theory that a transitional “macroweather” regime exists on a planet other than Earth. They used information collected from the Viking Mars lander mission from the 1970s and 1980s, and more recent data from the Mars Global Surveyor.
By taking into account how the sun heats Mars, as well as the thickness of the planet’s atmosphere, the scientists predicted that temperatures and wind would fluctuate on Mars similar to how they fluctuate on Earth. However, this transition from weather to macroweather would take place over 1.8 Martian days (about two Earth days), compared with a week to 10 days here on Earth.
“Our analysis of the data from Mars confirmed this prediction quite accurately,” said Shaun Lovejoy, a physics professor at McGill University in Montreal, Canada, and lead author of the paper. “This adds to evidence, from studies of Earth’s atmosphere and oceans, that the sun plays a central role in shaping the transition from short-term weather fluctuations to macroweather.”
The findings also indicate that weather on Mars can be predicted with some skill only two days in advance, compared to 10 days on Earth.
“We’re going to have a very hard time predicting the weather on Mars beyond two days given what we have found in weather records there,” said co-author Jan-Peter Muller from the University College London Mullard Space Science Laboratory in the UK, “which could prove tricky for the European lander and rover.”
This research promises to advance scientists’ understanding of the dynamics of Earth’s own atmosphere, and could potentially provide insights into the weather of Venus, Saturn’s moon Titan, and possibly the gas giants Jupiter, Saturn, Uranus, and Neptune.
As always, in learning about other planets and their climates, scientists are finding that the planets of our Solar System may have more in common with Earth than previously thought. Because of this, studying these other worlds will inevitably help us to better understand our own.
Hurricane Gonzalo, the first major Atlantic Ocean basin hurricane in three years, has strengthened to a dangerous Category 4 storm, threatening Bermuda and forcing a postponement of the upcoming launch of the Orbital Sciences Antares rocket to the space station from the Virginia shore to no earlier than Oct. 27.
A hurricane warning is in effect for the entire island of Bermuda.
NASA and Orbital Sciences had no choice but to delay the Antares blastoff from Oct. 24 to no earlier than Oct. 27 because Bermuda is home to an “essential tracking site” that must be operational to ensure public safety in case of a launch emergency situation.
Antares had been slated for an early evening liftoff with the Cygnus cargo carrier on the Orb-3 mission to the International Space Station (ISS).
NASA and Orbital issued the following statement:
“Due to the impending arrival of Hurricane Gonzalo on the island of Bermuda, where an essential tracking site used to ensure public safety during Antares launches is located, the previously announced “no earlier than” (NET) launch date of October 24 for the Orb-3 CRS mission to the International Space Station for NASA is no longer feasible.”
The powerful Gonzalo is currently expected to make a direct hit on Bermuda on Friday afternoon, Oct. 17. It’s packing devastating maximum sustained winds exceeding 145 mph (225 kph).
NASA and NOAA satellites including the Terra, Aqua and GOES-East satellites are providing continuous coverage of Hurricane Gonzalo as it moves toward Bermuda, according to a NASA update today.
Tropical storm force winds and 20 to 30 foot wave heights are expected to impact Bermuda throughout Friday and continue through Saturday and into Sunday.
“The National Hurricane Center expects hurricane-force winds, and rainfall totals of 3 to 6 inches in Bermuda. A storm surge with coastal flooding can be expected in Bermuda, with large and destructive waves along the coast. In addition, life-threatening surf and riptide conditions are likely in the Virgin Islands, Puerto Rico, Dominican Republic, Bahamas. Those dangerous conditions are expected along the U.S. East Coast and Bermuda today, Oct. 16,” according to NASA.
After the hurricane passes, a team will be sent to assess the impact of the storm on Bermuda and the tracking station. Further delays are possible if Bermuda’s essential infrastructure systems are damaged, such as power, transportation and communications.
The Antares/Cygnus rocket and cargo ship launch from the Mid-Atlantic Regional Spaceport at NASA’s Wallops Flight Facility along the eastrn shore of Virginia.
Liftoff is currently target for October 27 at 6:44 p.m. (EDT). The rendezvous and berthing of Cygnus with the ISS remains on November 2, with grapple of the spacecraft by the station’s robotic arm at approximately 4:58 a.m. (EST), according to a NASA update.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
138 million miles and 10 months journey from planet Earth, MAVEN moved into its new home around the planet Mars this evening. Flight controllers at Lockheed Martin Space Systems in Littleton, Colorado anxiously monitored the spacecraft’s progress as onboard computers successfully eased the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft into Mars orbit at 10:24 p.m. Eastern Daylight Time.
Shortly before orbital insertion, six small thrusters were fired to steady the spacecraft so it would enter orbit in the correct orientation. This was followed by a 33-minute burn to slow it down enough for Mars’ gravity to capture the craft into an elliptical orbit with a period of 35 hours. Because it takes radio signals traveling at the speed of light 12 minutes to cross the gap between Mars and Earth, the entire orbital sequence was executed by onboard computers. There’s no chance to change course or make corrections, so the software has to work flawlessly. It did. The burn, as they said was “nominal”, science-speak for came off without a hitch.
“This was a very big day for MAVEN,” said David Mitchell, MAVEN project manager from NASA’s Goddard Space Flight Center, Greenbelt, Maryland. “We’re very excited to join the constellation of spacecraft in orbit at Mars and on the surface of the Red Planet. Congratulations to the team for a job well done today.”
Over the next six weeks, controllers will test MAVEN’s instruments and shape its orbit into a long ellipse with a period of 4.5 hours and a low point of just 93 miles (150 km), close enough to get a taste of the planet’s upper atmosphere. MAVEN’s one-Earth-year long primary mission will study the composition and structure of Mars’ atmosphere and how it’s affected by the sun and solar wind. At least 2,000 Astronomers want to determine how the planet evolved from a more temperate climate to the current dry, frigid desert.
Vast quantities of water once flowed over the dusty red rocks of Mars as evidenced by ancient riverbeds, outflow channels carved by powerful floods, and rocks rounded by the action of water. For liquid water to flow on its surface without vaporizing straight into space, the planet must have had a much denser atmosphere at one time.
Mars’ atmospheric pressure is now less than 1% that of Earth’s. As for the water, what’s left today appears locked up as ice in the polar caps and subsurface ice. So where did it go all the air go? Not into making rocks apparently. On Earth, much of the carbon dioxide from volcanic outgassing in the planet’s youth dissolved in water and combined with rocks to form carbon-bearing rocks called carbonates. So far, carbonates appear to be rare on Mars. Little has been seen from orbit and in situ with the rovers.
During the year-long mission, MAVEN will dip in and out of the atmosphere some 2,000 times or more to measure what and how much Mars is losing to space. Without the protection of a global magnetic field like the Earth’s, it’s thought that the solar wind eats away at the Martian atmosphere by ionizing (knocking off electrons) its atoms and molecules. Once ionized, the atoms swirl up the magnetic field embedded in the wind and are carried away from the planet.
Scientists will coordinate with the Curiosity rover, which can determine the atmospheric makeup at ground level. Although MAVEN won’t be taking pictures, its three packages of instruments will be working daily to fill gaps in the story of how Mars became the Red Planet and we the Blue.
For more on the ongoing progress of MAVEN later tonight and tomorrow, stop by NASA TV online. You can also stay in touch by following the hashtags #MAVEN and #JourneytoMars on social media channels including Twitter, Instagram and Facebook. Twitter updates will be posted throughout on the agency’s official accounts @NASA, @MAVEN2Mars and @NASASocial.
On February 24, 2009, the launch of the Orbiting Carbon Observatory (OCO) mission — designed to study the global fate of carbon dioxide — resulted in failure. Shortly after launch, the rocket nose didn’t separate as expected, and the satellite could not be released.
But now, a carbon copy of the original mission, called OCO-2 is slated to launch on July 1, 2014.
The original failure ended in “heartbreak. The entire mission was lost. We didn’t even have one problem to solve,” said OCO-2 Project Manager Ralph Basilio in a press conference earlier today. “On behalf of the entire team that worked on the original OCO mission, we’re excited about this opportunity … to finally be able to complete some unfinished business.”
The motivation for the mission is simple: in the last few hundred years, human beings have played a large role in the planet-wide balancing act called the carbon cycle. Our activities, such as fossil fuel burning and deforestation are pushing the cycle out of its natural balance, adding more carbon dioxide to the atmosphere.
“There’s a steady increase in atmospheric carbon dioxide concentrations over time,” said OCO-2 Project Scientist Mike Gunson. “But at the same time, we can see that this has an annual cycle of dropping every summer, in this case in the northern hemisphere, as the forests and plants grow. And this is the Earth breathing.”
Carbon dioxide is both one of the best-measured greenhouse gases and least-measured. Half of the emissions in the atmosphere become largely distributed around the globe in a matter of months. But the other half of the emissions — the half that is being absorbed through natural processes into the land or the ocean — is not evenly distributed.
To understand carbon dioxide absorption, we need a high-resolution global map.
This is where the launch failure of OCO proved to be a blessing in disguise. It gave OCO-2 scientists a chance to work with project managers of the Japanese Greenhouse Gases Observing Satellite (GOSAT), which successfully launched in 2009. The unexpected collaboration allowed them to stumble upon a hidden surprise.
“A couple of my colleagues made what I think is a fantastic discovery,” said Gunson. They discovered fluorescent light from vegetation.
As plants absorb sunlight, some of the light is dissipated as heat, while some is re-emitted at longer wavelengths as fluorescence. Although scientists have measured fluorescence in laboratory settings and ground-based experiments, they have never done so from space.
Measuring the fluorescent glow proves to be a challenge because the tiny signal is overpowered by reflected sunlight. Researchers found that by tuning their GOSAT spectrometer — an instrument that can measure light across the electromagnetic spectrum — to look at very narrow channels, they could see parts of the spectrum where there was fluorescence but less reflect sunlight.
This surprise will give OCO-2 an unexpected global view from space, shedding new light on the productivity of vegetation on land. It will provide a regional map of absorbed carbon dioxide, helping scientists to estimate photosynthesis rates over vast scales and better understand the second half of the carbon cycle.
“The OCO-2 satellite has one instrument: a three-channel grating spectrometer,” said OCO-2 Program Executive Betsy Edwards. “But with this one instrument we’re going to collect hundreds of thousands of measurements each day, which will then provide a global description of carbon dioxide in the atmosphere. It’s going to be an unprecedented level of coverage and resolution, something we have not seen before with previous spacecraft.”
OCO-2 will result in nearly 100 times more observations of both carbon dioxide and fluorescence than GOSAT. It will launch from Vandenberg Air Force Base in California at 2:56 a.m. on July 1.
“Climate change is the challenge of our generation,” said Edwards. “NASA is particularly ready to … provide information, on documenting and understanding what these changes are on the climate, in predicting the impact of these changes to the Earth, and in sharing all of this information that we gather for the benefit of society.”