In recent years research into extremophiles has captured the interest of astrobiologists. The discovery of lifeforms in some of Earth’s most extreme environments has helped shape our thinking about extraterrestrial life. Life on other worlds may not need the kind of temperate, balanced environment that most life on Earth is adapted to.Continue reading “Finally! Scientists Find a Place on Earth with Liquid Water But No Life”
The question of how life on Earth first emerged is one that humans have been asking themselves since time immemorial. While scientists are relatively confident about when it happened, there has been no definitive answer as to why it did. How did amino acids, the chemical building blocks of life, come together roughly four billion years ago to create the first protein molecules?
While that question is still unanswered, scientists are making new discoveries that could help narrow it down. For instance, a team of researchers from the Georgia Institute of Technology’s Center for Chemical Evolution (CCT) recently conducted a study that showed how some of the earliest predecessors of the protein molecule may have spontaneously linked up to form a chain.Continue reading “All Life on Earth is Made up of the Same 20 Amino Acids. Scientist Now Think They Know Why”
In the search for life beyond Earth, scientists have turned up some very interesting possibilities and clues. On Mars, there are currently eight functioning robotic missions on the surface of or in orbit investigating the possibility of past (and possibly present) microbial life. Multiple missions are also being planned to explore moons like Titan, Europa, and Enceladus for signs of methanogenic or extreme life.
But what about Earth’s closest neighboring planet, Venus? While conditions on its surface are far too hostile for life as we know it there are those who think it could exist in its atmosphere. In a new study, a team of international researchers addressed the possibility that microbial life could be found in Venus’ cloud tops. This study could answer an enduring mystery about Venus’ atmosphere and lead to future missions to Earth’s “Sister Planet”.
The study, titled “Venus’ Spectral Signatures and the Potential for Life in the Clouds“, recently appeared in the journal Astrobiology. The study was led by Sanjay Limaye of the University of Wisconsin-Madison’s Space Science and Engineering Center and included members from NASA’s Ames Research Center, NASA’s Jet Propulsion Laboratory, California State Polytechnic University, the Birbal Sahni Institute of Palaeosciences, and the University of Zielona Góra.
For the sake of their study, the team considered the presence of UV contrasts in Venus’ upper atmosphere. These dark patches have been a mystery since they were first observered nearly a century ago by ground-based telescopes. Since then, scientists have learned that they are made up of concentrated sulfuric acid and other unknown light-absorbing particles, which the team argues could be microbial life.
As Limaye indicated in a recent University of Wisconsin-Madison press statement:
“Venus shows some episodic dark, sulfuric rich patches, with contrasts up to 30 – 40 percent in the ultraviolet, and muted in longer wavelengths. These patches persist for days, changing their shape and contrasts continuously and appear to be scale dependent.”
To illustrate the possibility that these streaks are the result of microbial life, the team considered whether or not extreme bacteria could survive in Venus’ cloud tops. For instance, the lower cloud tops of Venus (47.5 to 50.5 km above the surface) are known to have moderate temperature conditions (~60 °C; 140 °F) and pressure conditions that are similar to that of Earth at sea level (101.325 kPa).
This is far more hospitable than conditions on the surface, where temperatures reach 737 K (462 C; 860 F) and atmospheric pressure is 9200 kPa (92 times that of Earth at sea level). In addition, they considered how on Earth, bacteria has been found at altitudes as high as 41 km (25 mi). On top of that, there are many cases where extreme bacteria here on Earth that could survive in an acidic environment.
As Rakesh Mogul, a professor of biological chemistry at California State Polytechnic University and a co-author on the study, indicated, “On Earth, we know that life can thrive in very acidic conditions, can feed on carbon dioxide, and produce sulfuric acid.” This is consistent with the presence of micron-sized sulfuric acid aerosols in Venus upper atmosphere, which could be a metabolic by-product.
In addition, the team also noted that according to some models, Venus had a habitable climate with liquid water on its surface for as long as two billion years – which is much longer than what is believed to have occurred on Mars. In short, they speculate that life could have evolved on the surface of Venus and been swept up into the atmosphere, where it survived as the planet experienced its runaway greenhouse effect.
This study expands on a proposal originally made by Harold Morowitz and famed astronomer Carl Sagan in 1967 and which was investigated by a series of probes sent to Venus between 1962 and 1978. While these missions indicated that surface conditions on Venus ruled out the possibility of life, they also noted that conditions in the lower and middle portions of Venus’ atmosphere – 40 to 60 km (25 – 27 mi) altitude – did not preclude the possibility of microbial life.
For years, Limaye has been revisiting the idea of exploring Venus’ atmosphere for signs of life. The inspiration came in part from a chance meeting at a teachers workshop with Grzegorz Slowik – from the University of Zielona Góra in Poland and a co-author on the study – who told him of how bacteria on Earth have light-absorbing properties similar to the particles that make up the dark patches observed in Venus’ clouds.
While no probe that has sampled Venus’ atmosphere has been capable of distinguishing between organic and inorganic particles, the ones that make up Venus’ dark patches do have comparable dimensions to some bacteria on Earth. According to Limaye and Mogul, these patches could therefore be similar to algae blooms on Earth, consisting of bacteria that metabolizes the carbon dioxide in Venus’ atmosphere and produces sulfuric acid aerosols.
In the coming years, Venus’ atmosphere could be explored for signs of microbial life by a lighter than air aircraft. One possibility is the Venus Aerial Mobil Platform (VAMP), a concept currently being researched by Northrop Grumman (shown above). Much like lighter-than-air concepts being developed to explore Titan, this vehicle would float and fly around in Venus’ atmosphere and search the cloud tops for biosignatures.
Another possibility is NASA’s possible participation in the Russian Venera-D mission, which is currently scheduled to explore Venus during the late 2020s. This mission would consist of a Russian orbiter and lander to explore Venus’ atmosphere and surface while NASA would contribute a surface station and maneuverable aerial platform.
Another mystery that such a mission could explore, which has a direct bearing on whether or not life may still exist on Venus, is when Venus’ liquid water evaporated. In the last billion years or so, the extensive lava flows that cover the surface have either destroyed or covered up evidence of the planet’s early history. By sampling Venus’ clouds, scientists could determine when all of the planet’s liquid water disappeared, triggering the runaway greenhouse effect that turned it into a hellish landscape.
NASA is currently investigating other concepts to explore Venus’ hostile surface and atmosphere, including an analog robot and a lander that would use a Sterling engine to turn Venus’ atmosphere into a source of power. And with enough time and resources, we might even begin contemplating building floating cities in Venus atmosphere, complete with research facilities.
For decades, ever since the Pioneer and Voyager missions passed through the outer Solar System, scientists have speculated that life might exist within icy bodies like Jupiter’s moon Europa. However, thanks the Cassini mission, scientists now believe that other moons in the outer Solar System – such as Saturn’s moon Enceladus – could possibly harbor life as well.
For instance, Cassini observed plume activity coming from Enceladus’ southern polar region that indicated the presence of hydrothermal activity inside. What’s more, these plumes contained organic molecules and hydrated minerals, which are potential indications of life. To see if life could thrive inside this moon, a team of scientists conducted a test where strains of Earth bacteria were subjected to conditions similar to what is found inside Enceladus.
The study which details their findings recently appeared in the journal Nature Communications under the title “Biological methane production under putative Enceladus-like conditions“. The study was led by Ruth-Sophie Taubner from the University of Vienna, and included members from the Johannes Kepler University Linz, Ecotechnology Austria, the University of Bremen, and the University of Hamburg.
For the sake of their study, the team chose to work with three strains of methanogenic archaea known as methanothermococcus okinawensis. This type of microorganism thrives in low-oxygen environments and consumes chemical products known to exist on Enceladus – such as methane (CH4), carbon dioxide (CO2 ) and molecular hydrogen (H2) – and emit methane as a metabolic byproduct. As they state:
“To investigate growth of methanogens under Enceladus-like conditions, three thermophilic and methanogenic strains, Methanothermococcus okinawensis (65 °C), Methanothermobacter marburgensis (65 °C), and Methanococcus villosus (80 °C), all able to fix carbon and gain energy through the reduction of CO2 with H2 to form CH4, were investigated regarding growth and biological CH4 production under different headspace gas compositions…”
These strains were selected because of their ability to grow in a temperature range that is characteristic of the vicinity around hydrothermal vents, in a chemically defined medium, and at low partial pressures of molecular hydrogen. This is consistent with what has been observed in Enceladus’ plumes and what is believed to exist within the moon’s interior.
These types of archaea can still be found on Earth today, lingering in deep-see fissures and around hydrothermal vents. In particular, the strain of M. okinawensis has been determined to exist in only one location around the deep-sea hydrothermal vent field at Iheya Ridge in the Okinawa Trough near Japan. Since this vent is located at a depth of 972 m (3189 ft) below sea level, this suggests that this strain has a tolerance toward high pressure.
For many years, scientists have suspected that Earth’s hydrothermal vents played a vital role in the emergence of life, and that similar vents could exist within the interior of moons like Europa, Ganymede, Titan, Enceladus, and other bodies in the outer Solar System. As a result, the research team believed that methanogenic archaea could also exist within these bodies.
After subjecting the strains to Enceladus-like temperature, pressure and chemical conditions in a laboratory environment, they found that one of the three strains was able to flourish and produce methane. The strain even managed to survive after the team introduced harsh chemicals that are present on Enceladus, and which are known to inhibit the growth of microbes. As they conclude in their study:
“In this study, we show that the methanogenic strain M. okinawensis is able to propagate and/or to produce CH4 under putative Enceladus-like conditions. M. okinawensis was cultivated under high-pressure (up to 50 bar) conditions in defined growth medium and gas phase, including several potential inhibitors that were detected in Enceladus’ plume.”
From this, they determined that some of the methane found in Enceladus’ plumes were likely produced by the presence of methanogenic microbes. As Simon Rittmann, a microbiologist at the University of Vienna and lead author of the study, explained in an interview with The Verge. “It’s likely this organism could be living on other planetary bodies,” he said. “And it could be really interesting to investigate in future missions.”
In the coming decades, NASA and other space agencies plan to send multiple mission to the Jupiter and Saturn systems to investigate their “ocean worlds” for potential signs of life. In the case of Enceladus, this will most likely involve a lander that will set down around the southern polar region and collect samples from the surface to determine the presence of biosignatures.
Alternately, an orbiter mission may be developed that will fly through Enceladus’ plumes and collect bioreadings directly from the moon’s ejecta, thus picking up where Cassini left off. Whatever form the mission takes, the discoveries are expected to be a major breakthrough. At long last, we may finally have proof that Earth is not the only place in the Solar System where live can exist.
Be sure to check out John Michael Godier’s video titled “Encedalus and the Conditions for Life” as well:
5 years after a heart throbbing Martian touchdown, Curiosity is climbing Vera Rubin Ridge in search of “aqueous minerals” and “clays” for clues to possible past life while capturing “truly breathtaking” vistas of humongous Mount Sharp – her primary destination – and the stark eroded rim of the Gale Crater landing zone from ever higher elevations, NASA scientists tell Universe Today in a new mission update.
“Curiosity is doing well, over five years into the mission,” Michael Meyer, NASA Lead Scientist, Mars Exploration Program, NASA Headquarters told Universe Today in an interview.
“A key finding is the discovery of an extended period of habitability on ancient Mars.”
The car-sized rover soft landed on Mars inside Gale Crater on August 6, 2012 using the ingenious and never before tried “sky crane” system.
A rare glimpse of Curiosity’s arm and turret mounted skyward pointing drill is illustrated with our lead mosaic from Sol 1833 of the robot’s life on Mars – showing a panoramic view around the alien terrain from her current location in October 2017 while actively at work analyzing soil samples.
“Your mosaic is absolutely gorgeous!’ Jim Green, NASA Director Planetary Science Division, NASA Headquarters, Washington D.C., told Universe Today
“We are at such a height on Mt Sharp to see the rim of Gale Crater and the top of the mountain. Truly breathtaking.”
The rover has ascended more than 300 meters in elevation over the past 5 years of exploration and discovery from the crater floor to the mountain ridge. She is driving to the top of Vera Rubin Ridge at this moment and always on the lookout for research worthy targets of opportunity.
Additionally, the Sol 1833 Vera Rubin Ridge mosaic, stitched by the imaging team of Ken Kremer and Marco Di Lorenzo, shows portions of the trek ahead to the priceless scientific bounty of aqueous mineral signatures detected by spectrometers years earlier from orbit by NASA’s fleet of Red Planet orbiters.
“Curiosity is on Vera Rubin Ridge (aka Hematite Ridge) – it is the first aqueous mineral signature that we have seen from space, a driver for selecting Gale Crater,” NASA HQ Mars Lead Scientist Meyer elaborated.
“And now we have access to it.”
The Sol 1833 photomosaic illustrates Curiosity maneuvering her 7 foot long (2 meter) robotic arm during a period when she was processing and delivering a sample of the “Ogunquit Beach” for drop off to the inlet of the CheMin instrument earlier in October. The “Ogunquit Beach” sample is dune material that was collected at Bagnold Dune II this past spring.
The sample drop is significant because the drill has not been operational for some time.
“Ogunquit Beach” sediment materials were successfully delivered to the CheMin and SAM instruments over the following sols and multiple analyses are in progress.
To date three CheMin integrations of “Ogunquit Beach” have been completed. Each one brings the mineralogy into sharper focus.
What’s the status of the rover health at 5 years, the wheels and the drill?
“All the instruments are doing great and the wheels are holding up,” Meyer explained.
“When 3 grousers break, 60% life has been used – this has not happened yet and they are being periodically monitored. The one exception is the drill feed (see detailed update below).”
NASA’s 1 ton Curiosity Mars Science Laboratory (MSL) rover is now closer than ever to the mineral signatures that were the key reason why Mount Sharp was chosen as the robots landing site years ago by the scientists leading the unprecedented mission.
Along the way from the ‘Bradbury Landing’ zone to Mount Sharp, six wheeled Curiosity has often been climbing. To date she has gained over 313 meters (1027 feet) in elevation – from minus 4490 meters to minus 4177 meters today, Oct. 19, 2017, said Meyer.
The low point was inside Yellowknife Bay at approx. minus 4521 meters.
VRR alone stands about 20 stories tall and gains Curiosity approx. 65 meters (213 feet) of elevation to the top of the ridge. Overall the VRR traverse is estimated by NASA to take drives totaling more than a third of a mile (570 m).
“Vera Rubin Ridge” or VRR is also called “Hematite Ridge.” It’s a narrow and winding ridge located on the northwestern flank of Mount Sharp. It was informally named earlier this year in honor of pioneering astrophysicist Vera Rubin.
The intrepid robot reached the base of the ridge in early September.
The ridge possesses steep cliffs exposing stratifications of large vertical sedimentary rock layers and fracture filling mineral deposits, including the iron-oxide mineral hematite, with extensive bright veins.
VRR resists erosion better than the less-steep portions of the mountain below and above it, say mission scientists.
What’s ahead for Curiosity in the coming weeks and months exploring VRR before moving onward and upwards to higher elevation?
“Over the next several months, Curiosity will explore Vera Rubin Ridge,” Meyer replied.
“This will be a big opportunity to ground-truth orbital observations. Of interest, so far, the hematite of VRR does not look that different from what we have been seeing all along the Murray formation. So, big question is why?”
“The view from VRR also provides better access to what’s ahead in exploring the next aqueous mineral feature – the clay, or phyllosilicates, which can be indicators of specific environments, putting constraints on variables such as pH and temperature,” Meyer explained.
The clay minerals or phyllosilicates form in more neutral water, and are thus extremely scientifically interesting since pH neutral water is more conducive to the origin and evolution of Martian microbial life forms, if they ever existed.
How far away are the clays ahead and when might Curiosity reach them?
“As the crow flies, the clays are about 0.5 km,” Meyer replied. “However, the actual odometer distance and whether the clays are where we think they are – area vs. a particular location – can add a fair degree of variability.”
The clay rich area is located beyond the ridge.
Over the past few months Curiosity make rapid progress towards the hematite-bearing location of Vera Rubin Ridge after conducting in-depth exploration of the Bagnold Dunes earlier this year.
“Vera Rubin Ridge is a high-standing unit that runs parallel to and along the eastern side of the Bagnold Dunes,” said Mark Salvatore, an MSL Participating Scientist and a faculty member at Northern Arizona University, in a mission update.
“From orbit, Vera Rubin Ridge has been shown to exhibit signatures of hematite, an oxidized iron phase whose presence can help us to better understand the environmental conditions present when this mineral assemblage formed.”
Curiosity is using the science instruments on the mast, deck and robotic arm turret to gather detailed research measurements with the cameras and spectrometers. The pair of miniaturized chemistry lab instruments inside the belly – CheMin and SAM – are used to analyze the chemical and elemental composition of pulverized rock and soil gathered by drilling and scooping selected targets during the traverse.
A key instrument is the drill which has not been operational. I asked Meyer for a drill update.
“The drill feed developed problems retracting (two stabilizer prongs on either side of the drill retract, controlling the rate of drill penetration),” Meyer replied.
“Because the root cause has not been found (think FOD) and the concern about the situation getting worse, the drill feed has been retracted and the engineers are working on drilling without the stabilizing prongs.”
“Note, a consequence is that you can still drill and collect sample but a) there is added concern about getting the drill stuck and b) a new method of delivering sample needs to be developed and tested (the drill feed normally needs to be moved to move the sample into the chimera). One option that looks viable is reversing the drill – it does work and they are working on the scripts and how to control sample size.”
Ascending and diligently exploring the sedimentary lower layers of Mount Sharp, which towers 3.4 miles (5.5 kilometers) into the Martian sky, is the primary destination and goal of the rover’s long term scientific expedition on the Red Planet.
“Lower Mount Sharp was chosen as a destination for the Curiosity mission because the layers of the mountain offer exposures of rocks that record environmental conditions from different times in the early history of the Red Planet. Curiosity has found evidence for ancient wet environments that offered conditions favorable for microbial life, if Mars has ever hosted life,” says NASA.
Stay tuned. In part 2 we’ll discuss the key findings from Curiosity’s first 5 years exploring the Red Planet.
As of today, Sol 1850, Oct. 19, 2017, Curiosity has driven over 10.89 miles (17.53 kilometers) since its August 2012 landing inside Gale Crater from the landing site to the ridge, and taken over 445,000 amazing images.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
In late 1970s and early 80s, scientists got their first detailed look at Saturn’s largest moon Titan. Thanks to the Pioneer 11 probe, which was then followed by the Voyager 1 and 2 missions, the people of Earth were treated to images and readings of this mysterious moon. What these revealed was a cold satellite that nevertheless had a dense, nitrogen-rich atmosphere.
Thanks to the Cassini-Huygens mission, which reached Titan in July of 2004 and will be ending its mission on September 15th, the mysteries of this moon have only deepened. Hence why NASA hopes to send more missions there in the near future, like the Dragonfly concept. This craft is the work of the John Hopkins University Applied Physics Laboratory (JHUAPL), which they just submitted an official proposal for.
Essentially, Dragonfly would be a New Frontiers-class mission that would use a dual-quadcopter setup to get around. This would enable vertical-takeoff and landing (VTOL), ensuring that the vehicle would be capable of exploring Titan’s atmosphere and conducting science on the surface. And of course, it would also investigate Titan’s methane lakes to see what kind of chemistry is taking place within them.
The goal of all this would be to shed light on Titan’s mysterious environment, which not only has a methane cycle similar to Earth’s own water cycle, but is rich in prebiotic and organic chemistry. In short, Titan is an “ocean world” of our Solar System – along with Jupiter’s moons Europa and Ganymede, and Saturn’s moon of Enceladus – that could contain all the ingredients necessary for life.
What’s more, previous studies have shown that the moon is covered in rich deposits of organic material that are undergoing chemical processes, ones that might be similar to those that took place on Earth billions of years ago. Because of this, scientists have come to view Titan as a sort of planetary laboratory, where the chemical reactions that may have led to life on Earth could be studied.
As Elizabeth Turtle, a planetary scientist at JHUAPL and the principal investigator for the Dragonfly mission, told Universe Today via email:
“Titan offers abundant complex organics on the surface of a water-ice-dominated ocean world, making it an ideal destination to study prebiotic chemistry and to document the habitability of an extraterrestrial environment. Because Titan’s atmosphere obscures the surface at many wavelengths, we have limited information about the materials that make up the surface and how they’re processed. By making detailed surface composition measurements in multiple locations, Dragonfly would reveal what the surface is made of and how far prebiotic chemistry has progressed in environments that provide known key ingredients for life, identifying the chemical building blocks available and processes at work to produce biologically relevant compounds.”
In addition, Dragonfly would also use remote-sensing observations to characterize the geology of landing sites. In addition to providing context for the samples, it would also allow for seismic studies to determine the structure of the Titan and the presence of subsurface activity. Last, but not least, Dragonfly would use meteorology sensors and remote-sensing instruments to gather information on the planet’s atmospheric and surface conditions.
While multiple proposals have been made for a robotic explorer mission of Titan, most of these have taken the form of either an aerial platforms or a combination balloon and a lander. The Aerial Vehicle for In-situ and Airborne Titan Reconnaissance (AVIATR), a proposal made in the past by Jason Barnes and a team of researchers from the University of Idaho, is an example of the former.
In the latter category, you have concepts like the Titan Saturn System Mission (TSSM), a concept that was being jointly-developed by the European Space Agency (ESA) and NASA. An Outer Planets Flagship Mission concept, the design of the TSSM consisted of three elements – a NASA orbiter, an ESA-designed lander to explore Titan’s lakes, and an ESA-designed Montgolfiere balloon to explore its atmosphere.
What separates Dragonfly from these and other concepts is its ability to conduct aerial and ground-based studies with a single platform. As Dr. Turtle explained:
“Dragonfly would be an in situ mission to perform detailed measurements of Titan’s surface composition and conditions to understand the habitability of this unique organic-rich ocean world. We proposed a rotorcraft to take advantage of Titan’s dense, calm atmosphere and low gravity (which make flight easier on Titan than it is on Earth) to convey a capable suite of instruments from place to place — 10s to 100s of kilometers apart — to make measurements in different geologic settings. Unlike other aerial concepts that have been considered for Titan exploration (of which there have been several), Dragonfly would spend most of its time on the surface performing measurements, before flying to another site.”
Dragonfly‘s suite of instruments would include mass spectrometers to study the composition of the surface and atmosphere; gamma-ray spectrometers, which would measure the composition of the subsurface (i.e. looking for evidence of an interior ocean); meteorology and geophysics sensors, which would measure wind, atmospheric pressure, temperature and seismic activity; and a camera suite to snap pictures of the surface.
Given Titan’s dense atmosphere, solar cells would not be an effective option for a robotic mission. As such, the Dragonfly would rely on a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) for power, similar to what the Curiosity rover uses. While robotic missions that rely on nuclear power sources are not exactly cheap, they do enable missions that can last for years at a time and conduct invaluable research (as Curiosity has shown).
As Peter Bedini – the Program Manager at the JHUAPL Space Department and Dragonfly’s project manager – explained, this would allow for a long-term mission with significant returns:
“We could take a lander, put it on Titan, take these four measurements at one place, and significantly increase our understanding of Titan and similar moons. However, we can multiply the value of the mission if we add aerial mobility, which would enable us to access a variety of geologic settings, maximizing the science return and lowering mission risk by going over or around obstacles.”
In the end, a mission like Dragonfly would be able to investigate how far prebiotic chemistry has progressed on Titan. These types of experiments, where organic building blocks are combined and exposed to energy to see if life emerges, cannot be performed in a laboratory (mainly because of the timescales involved). As such, scientists hope to see how far things have progressed on Titan’s surface, where prebiotic conditions have existed for eons.
In addition, scientists will also be looking for chemical signatures that indicate the presence of water and/or hydrocarbon-based life. In the past, it has been speculated that life could exist within Titan’s interior, and that exotic methanogenic lifeforms could even exist on its surface. Finding evidence of such life would challenge our notions of where life can emerge, and greatly enhance the search for life within the Solar System and beyond.
As Dr. Turtle indicated, mission selection will be coming soon, and whether or not the Dragonfly mission will be sent to Titan should be decided in just a few years time:
“Later this fall, NASA will select a few of the proposed New Frontiers missions for further work in Phase A Concept Studies” she said. “Those studies would run for most of 2018, followed by another round of review. And the final selection of a flight mission would be in mid-2019… Missions proposed to this round of the New Frontiers Program would be scheduled to launch before the end of 2025.”
And be sure to check out this video of a possible Dragonfly mission, courtesy of the JHUAPL:
Further Reading: JHU Hub
Like all living creatures, stars have a natural lifespan. After going through their main sequence phase, they eventually exhaust their nuclear fuel and begin the slow process towards death. In our Sun’s case, this will consist of it growing in size and entering the Red Giant phase of its evolution. When that happens, roughly 5.4 billion years from now, the Sun will encompass the orbit’s of Mercury, Venus, and maybe even Earth.
However, even before this happens, astronomers theorize that the Sun will dramatically heat up, which will render Earth uninhabitable to most species. But according to a new study by a team of researchers from Oxford and the University of Harvard, the species known as tardigrades (aka. the “water bear”) will likely survive even after humanity and all other species have perished.
This study, which was recently published in the journal Scientific Reports under the title “The Resilience of Life to Astrophysical Events“, was conducted by Dr. David Sloan, Dr. Rafael Alves Batista – from the Department of Astrophysics at Oxford University – and Dr. Abraham Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA). As they indicate, previous studies into the effect Solar evolution will have on life have been rather lopsided.
Essentially, much attention has been dedicated to whether or not humanity will survive our Sun leaving its main sequence phase. Comparatively, very little research has been conducted on whether or not life itself (and which lifeforms) will be able to survive this change. As such, they considered the most statistically-likely events that would be capable of completely sterilizing an Earth-like planet, and sought to determine what lifeforms could endure them.
As Dr. Loeb told Universe Today via email, their team wanted to consider if there was an extinction-level event that could eliminate all life on Earth (not just humans):
“We wanted to find out how long life may survive on a planet once formed. Most previous studies focused on the survival of humans which are very sensitive to changes in the atmosphere or climate of the Earth and can be eliminated by the impact of an asteroid (nuclear winter) or bad politics.”
What they found was that the species Milnesium tardigradum would survive all potential astrophysical catastrophes. What’s more, they estimated that these creatures will be around for another 10 billion years at least – far longer than what is anticipated for the human race! As Loeb indicates, this was not an outcome that they were expecting.
“To our surprise, tardigrades are likely to survive all astrophysical catastrophes,” he said. “Most likely, the DNA of tardigrades is able to repair itself quickly due to damage encountered by the environment. The process is not fully understood, and there is a group at Harvard University who studies the SNA of tardigrades with the hope of understanding it better.”
To be fair, it has been known for some time that Tardigrades are the most resilient life form on Earth. Not only can they survive for up to 30 years without food or water (half their natural lifespan), they can also survive temperatures of up to 150 °C (302 °F) and as low as -200 °C (-328 °F). They have also shown themselves to be capable of enduring extremes in pressure, ranging from the 6000 atmospheres to the vacuum of open space.
Under these conditions, the research team concluded that they are likely to survive the Sun becoming a red giant and irradiating Earth, and will likely be alive even after the Sun has winked out of existence. On top of that, tardigrades can even be brought back to life, under the right circumstances. Much like all life on Earth, tradigrades need water to survive, even though they can survive in a dry state for extended periods of time – up to ten years, in fact.
But even after being deprived of water to the point of death, scientists have found that these organisms can be reanimated once water is reintroduced. This was demonstrated in 2007 when a batch of tardigrades was dehydrated before being launched to Low Earth Orbit (LEO). After being exposed to the hard vacuum of space and UV radiation for 10 days, they were returned to Earth and rehydrated – at which point, the majority were revived and able to produce viable embryos.
The team also concluded that other cataclysmic events – such as an asteroid strike, exploding stars (i.e. a supernovae) or gamma ray bursts – pose no existential threat to tardigrades. As Loeb explained:
“We have found that asteroid impacts are capable of boiling off all the oceans on Earth, but only if the asteroid is more massive than 1018 kg [10,000 trillion metric tons]. Such events are extremely rare and will not happen before the Sun will die; the probability of them happening earlier is less than one part in a million.”
In fact, the last time an object large enough to boil the oceans (2 x 1018 kg) collided with Earth occurred roughly 4.51 billion years ago. On this occasion, Earth was struck by a Mars-sized object named Theia, which is believed to be what caused the formation of the Moon. Today, there are only a dozen known asteroids or dwarf planets in the Solar System that have this kind of mass, and none of them will intersect the Earth’s orbit in the future.
As for supernova, they indicated that an exploding star would need to be 0.14 light-years from Earth in order for it to boil the oceans from its surface. Since the closest star to our Sun (Proxima Centauri) is 4.25 light years away, this scenario is not a foreseeable risk. As for gamma-ray bursts, which are even rarer than supernova, the team determined that they too are too far away from Earth to pose a threat.
The implications of this study are quite fascinating. For one, it reminds us just how fragile human life is compared to basic, microscopic life forms. It also demonstrates that similarly hardy organisms could exist in a variety of locations that we may have once considered too hostile for life. As Dr Rafael Alves Batista, one of the co-authors on the study, said in a University of Oxford press release:
“Without our technology protecting us, humans are a very sensitive species. Subtle changes in our environment impact us dramatically. There are many more resilient species’ on earth. Life on this planet can continue long after humans are gone. Tardigrades are as close to indestructible as it gets on Earth, but it is possible that there are other resilient species examples elsewhere in the Universe. In this context there is a real case for looking for life on Mars and in other areas of the Solar System in general. If Tardigrades are earth’s most resilient species, who knows what else is out there?’”
And as Dr. Loeb explained, studies like this have potential benefits that go far beyond assessing our own survivability. Not only do they help us understand life’s ability to endure catastrophic events – which is essential to understanding how and where life could emerge in the Universe – but they also offer possibilities on how we might better our own chances of survival.
“We get a better understanding of the conditions under which life will persist,” he said. “In about a billion years, when the Sun will heat up life will cease, but until then it will continue in some form. Understanding the self-repair mechanism of the DNA on tardigrades could potentially help in combating disease for humans as well.”
And all his time, we thought cockroaches were the toughest critters on the planet, what with their ability to withstand a nuclear holocaust. But these eight-legged creatures, which are arguably cuter than cockroaches too, clearly have the market on toughness cornered. We’re just lucky they only get up to 0.5 mm (0.02 in) in size, otherwise we might have something to worry about!
The Trump Administration has proposed a $19.1 Billion NASA budget request for Fiscal Year 2018, which amounts to a $0.5 Billion reduction compared to the recently enacted FY 2017 NASA Budget. Although it maintains many programs such as human spaceflight, planetary science and the Webb telescope, the budget also specifies significant cuts and terminations to NASA’s Earth Science and manned Asteroid redirect mission as well as the complete elimination of the Education Office.
Overall NASA’s FY 2018 budget is cut approximately 3%, or $560 million, for the upcoming fiscal year starting in October 2017 as part of the Trump Administration’s US Federal Budget proposal rolled out on May 23, and quite similar to the initial outline released in March.
The cuts to NASA are smaller compared to other Federal science agencies also absolutely vital to the health of US scientific research – such as the NIH, the NSF, the EPA, DOE and NIST which suffer unconscionable double digit slashes of 10 to 20% or more.
The highlights of NASA’s FY 2018 Budget were announced by NASA acting administrator Robert Lightfoot during a ‘State of NASA’ speech to agency employees held at NASA HQ, Washington, D.C. and broadcast to the public live on NASA TV.
Lightfoot’s message to NASA and space enthusiasts was upbeat overall.
“What this budget tells us to do is to keep going!” NASA acting administrator Robert Lightfoot said.
“Keep doing what we’ve been doing. It’s very important for us to maintain that course and move forward as an agency with all the great things we’re doing.”
“I want to reiterate how proud I am of all of you for your hard work – which is making a real difference around the world. NASA is leading the world in space exploration, and that is only possible through all of your efforts, every day.”
“We’re pleased by our top line number of $19.1 billion, which reflects the President’s confidence in our direction and the importance of everything we’ve been achieving.”
Lightfoot recalled the recent White House phone call from President Trump to NASA astronaut & ISS Station Commander Peggy Whitson marking her record breaking flight for the longest cumulative time in space by an American astronaut.
Thus Lightfoot’s vision for NASA has three great purposes – Discover, Explore, and Develop.
“NASA has a historic and enduring purpose. It can be summarized in three major strategic thrusts: Discover, Explore, and Develop. These correspond to our missions of scientific discovery, missions of exploration, and missions of new technology development in aeronautics and space systems.”
Lightfoot further recounted the outstanding scientific accomplishments of NASA’s Mars rover and orbiters paving the path for the agencies plans to send humans on a ‘Journey to Mars’ in the 2030s.
“We’ve had a horizon goal for some time now of reaching Mars, and this budget sustains that work and also provides the resources to keep exploring our solar system and look beyond it.”
Lightfoot also pointed to upcoming near term science missions- highlighting a pair of Mars landers – InSIGHT launching next year as well as the Mars 2020 rover. Also NASA’s next great astronomical observatory – the James Webb Space Telescope (JWST).
“In science, this budget supports approximately 100 missions: 40 missions currently preparing for launch & 60 operating missions.”
“The James Webb Space Telescope is built!” Lightfoot gleefully announced.
“It’s done testing at Goddard and now has moved to Johnson for tests to simulate the vacuum of space.”
JWST is the scientific successor to the Hubble Space Telescope and slated for launch in Oct. 2018. The budget maintains steady support for Webb.
The Planetary Sciences division receives excellent support with a $1.9 Billion budget request. It includes solid support for the two flagship missions – Mars 2020 and Europa Clipper as well as the two new Discovery class missions selected -Lucy and Psyche.
“The budget keeps us on track for the next selection for the New Frontiers program, and includes formulation of a mission to Jupiter’s moon Europa.”
“SLS and Orion are making great progress. They are far beyond concepts, and as I mentioned, components are being tested in multiple ways right now as we move toward the first flight of that integrated system.”
NASA is currently targeting the first integrated launch of SLS and Orion on the uncrewed Exploration Mission-1 (EM-1) for sometime in 2019.
Top NASA managers recently decided against adding a crew of two astronauts to the flight after conducting detailed agency wide studies at the request of the Trump Administration.
NASA would have needed an additional $600 to $900 to upgrade EM-1 with humans.
Unfortunately Trump’s FY 2018 NASA budget calls for a slight reduction in development funding for both SLS and Orion – thus making a crewed EM-1 flight fiscally unviable.
The budget request does maintain full funding for both of NASA’s commercial crew vehicles planned to restore launching astronauts to low Earth orbit (LEO) and the ISS from US soil on US rockets – namely the crewed Dragon and CST-100 Starliner – currently under development by SpaceX and Boeing – thus ending our sole reliance on Russian Soyuz for manned launches.
“Working with commercial partners, NASA will fly astronauts from American soil on the first new crew transportation systems in a generation in the next couple of years.”
“We need commercial partners to succeed in low-Earth orbit, and we also need the SLS and Orion to take us deeper into space than ever before.”
However the Trump Administration has terminated NASA’s somewhat controversial plans for the Asteroid Redirect Mission (ARM) – initiated under the Obama Administration – to robotically retrieve a near Earth asteroid and redirect it to lunar orbit for a visit by a crewed Orion to gather unique asteroidal samples.
“While we are ending formulation of a mission to an asteroid, known as the Asteroid Redirect Mission, many of the central technologies in development for that mission will continue, as they constitute vital capabilities needed for future human deep space missions.”
Key among those vital capabilities to be retained and funded going forward is Solar Electric Propulsion (SEP).
“Solar electric propulsion (SEP) for our deep space missions is moving ahead as a key lynchpin.”
The Trump Administration’s well known dislike for Earth science and disdain of climate change has manifested itself in the form of the termination of 5 current and upcoming science missions.
NASA’s FY 2018 Earth Science budget suffers a $171 million cut to $1.8 Billion.
“While we are not proposing to move forward with Orbiting Carbon Observatory-3 (OCO-3), Plankton, Aerosol, Cloud, ocean Ecosystem (PACE), Climate Absolute Radiance and Refractivity Observatory Pathfinder (CLARREO PF), and the Radiation Budget Instrument (RBI), this budget still includes significant Earth Science efforts, including 18 Earth observing missions in space as well as airborne missions.”
The DSCOVR Earth-viewing instruments will also be shut down.
NASA’s Office of Education will also be terminated completely under the proposed FY 2018 budget and the $115 million of funding excised.
“While this budget no longer supports the formal Office of Education, NASA will continue to inspire the next generation through its missions and the many ways that our work excites and encourages discovery by learners and educators. Let me tell you, we are as committed to inspiring the next generation as ever.”
Congress will now have its say and a number of Senators, including Republicans says Trumps budget is DOA.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
KENNEDY SPACE CENTER, FL – Bound for Bennu, NASA’s OSIRIS-REx robotic explorer began a trailblazing 7 year round trip sampling sortie on Sept. 8 in search of the origin of life with a spectacular sky show – thrilling spectators ringing the Florida Space Coast.
Hordes of space enthusiasts from all across the globe descended on the Kennedy Space Center and Cape Canaveral region for the chance of a lifetime to witness a once in a lifetime liftoff to the carbon rich asteroid – which could potentially bring back samples infused with the organic chemicals like amino acids that are the building blocks of life as we know it.
NASA’s Origins, Spectral Interpretation, Resource Identification, Security – Regolith Explorer (OSIRIS-REx) spacecraft departed Earth with an on time engine ignition of a United Launch Alliance Atlas V rocket under crystal clear skies on Thursday, September 8 at 7:05 p.m. EDT from Space Launch Complex 41 at Cape Canaveral Air Force Station.
Everything went exactly according to plan for the daring mission bolding seeking to gather rocks and soil from Bennu – using an ingenious robotic arm named TAGSAM – and bring at least a 60-gram (2.1-ounce) sample back to Earth in 2023 for study by scientists using the world’s most advanced research instruments.
“We got everything just exactly perfect,” said Dante Lauretta, the principal investigator for OSIRIS-REx at the University of Arizona, at the post launch briefing at the Kennedy Space Center. “We hit all our milestone within seconds of predicts.
The space rock measures about the size of a small mountain at about a third of a mile in diameter.
And the picture perfect near sunset launch rewarded photographers from near and far with a spectacular series of richly hued photo and video recordings.
So I’ve gathered here a variety of launch imagery from multiple vantage points shot by friends, colleagues and myself – for the enjoyment of readers of Universe Today and Beyond!
As you’ll see and hear the ULA Atlas V rocket integrated with OSIRIS-Rex on top thundered off the Cape’s pad 41 and shot skyward straight up along an equatorial path into Florida’s sun.
From every vantage point the rocket and its ever expanding vapor trail were visible for some 4 or 5 minutes or more. From my location on the roof of NASA’s Vehicle Assembly Building (VAB) the rocket finally arched over nearly straight above us and the sun produced a magnificent thin and nearly straight shadow of the vapor trail on the ground running out to the Atlantic Ocean towards Africa.
It was truly an unforgettable sight to behold. And folks at Playalinda Beach, the best public viewing spot just a few miles north of pad 40 had an uninhibited view of the rocket to the base of the pad – while they waded and swam in the oceans waters with waves crashing on shore as the Atlas rocket blasted to space.
OSIRIS-REx separated as planned from the Atlas V rockets liquid oxygen and liquid hydrogen fueled second stage rocket to fly free at 8:04 p.m. on Sept. 8 – 55 minutes after launch.
The pair of solar arrays deployed as planned to provide the probes life giving power.
The spacecraft was built by prime contractor Lockheed.
“The spacecraft is healthy and functioning properly,” Richard Kuhns, Lockheed Martin OSIRIS-REx program manager, told me in an interview at the post-launch briefing.
“The primary objective of the OSIRIS-Rex mission is to bring back pristine material from the surface of the carbonaceous asteroid Bennu, OSIRIS-Rex Principal Investigator Dante Lauretta told Universe Today in a prelaunch interview in the KSC cleanroom with the spacecraft as the probe was undergoing final preparations for shipment to the launch pad.
“We are interested in that material because it is a time capsule from the earliest stages of solar system formation.”
“It records the very first material that formed from the earliest stages of solar system formation. And we are really interested in the evolution of carbon during that phase. Particularly the key prebiotic molecules like amino acids, nucleic acids, phosphates and sugars that build up. These are basically the biomolecules for all of life.”
The asteroid is 1,614-foot (500 m) in diameter and crosses Earth’s orbit around the sun every six years.
After a two year flight through space, including an Earth swing by for a gravity assisted speed boost in 2017, OSIRIS-REx will reach Bennu in Fall 2018 to begin about 2 years of study in orbit to determine the physical and chemical properties of the asteroid in extremely high resolution.
While orbiting Bennu starting in 2018 it will move in close to explore the asteroid for about two years with its suite of science instruments, scanning in visible and infrared light. After a thorough site selection, it will move carefully towards the surface and extend the 11 foot long TAGSAM robotic arm and snatch pristine soil samples containing organic materials from the surface using the TAGSAM collection dish over just 3 to 5 seconds.
Once a good sample collection is confirmed, the dish will then be placed inside the Earth return canister and be brought back to Earth for study by researchers using all of the most sophisticated science instruments available to humankind.
Using the 11 foot long TAGSAM robotic arm that functions somewhat like a pogo stick, OSIRIS-REx will gather rocks and soil and bring at least a 60-gram (2.1-ounce) sample back to Earth on Sept 24, 2023. It has the capacity to scoop up to about 2 kg or more.
The two stage ULA Atlas V performed flawlessly and delivered OSIRIS-Rex into a hyperbolic trajectory away from Earth.
The 189 foot tall ULA Atlas V rocket launched in the rare 411 configuration for only the 3rd time on this mission – which is the 65th for the Atlas V.
The Atlas 411 vehicle includes a 4-meter diameter large Payload Fairing (PLF) and one solid rocket booster that augments the first stage. The Atlas booster for this mission is powered by the RD AMROSS RD-180 engine and the Centaur upper stage was powered by the Aerojet Rocketdyne RL10A.
The RD-180 burns RP-1 (Rocket Propellant-1 or highly purified kerosene) and liquid oxygen and delivers 860,200 lb of thrust at sea level.
The strap on solid delivers approximately 348,500 pounds of thrust.
The Centaur delivers 22, 230 lbf of thrust and burns liquid oxygen and liquid hydrogen.
The solid was jettisoned at 139 seconds after liftoff.
This is ULA’s eighth launch in 2016 and the 111th successful launch since the company was formed in December 2006.
OSIRIS-REx will return the largest sample from space since the American and Soviet Union’s moon landing missions of the 1970s.
Watch these pair of up close videos (from myself and Jeff Seibert) captured directly at the pad with the sights and sounds of the fury of launch:
Video Caption: ULA Atlas V rocket lifts off on September 8, 2016 from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s OSIRIS-REx asteroid sampling spacecraft, in this remote camera view taken from inside the launch pad perimeter. Credit: Ken Kremer/kenkremer.com
Video Caption: Compilation of my launch videos from the ULA Atlas 5 launch in support of the NASA OSIRIS_REx asteroid sample return mission to the asteroid Bennu (#101955). It was launched on September 8th, 2016 from Pad 41 of CCAFS. It is scheduled to land in UTAH with asteroid samples on September 24, 2023. Credit: Jeff Seibert
OSIRIS-REx is the third mission in NASA’s New Frontiers Program, following New Horizons to Pluto and Juno to Jupiter, which also launched on Atlas V rockets.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is responsible for overall mission management.
OSIRIS-REx complements NASA’s Asteroid Initiative – including the Asteroid Redirect Mission (ARM) which is a robotic spacecraft mission aimed at capturing a surface boulder from a different near-Earth asteroid and moving it into a stable lunar orbit for eventual up close sample collection by astronauts launched in NASA’s new Orion spacecraft. Orion will launch atop NASA’s new SLS heavy lift booster concurrently under development.
Watch for Ken’s continuing OSIRIS-REx mission and launch reporting from on site at the Kennedy Space Center and Cape Canaveral Air Force Station, FL.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Outer space touches us in so many ways. Meteors from ancient asteroid collisions and dust spalled from comets slam into our atmosphere every day, most of it unseen. Cosmic rays ionize the atoms in our upper air, while the solar wind finds crafty ways to invade the planetary magnetosphere and set the sky afire with aurora. We can’t even walk outside on a sunny summer day without concern for the Sun’s ultraviolet light burning out skin.
So perhaps you wouldn’t be surprised that over the course of Earth’s history, our planet has also been affected by one of the most cataclysmic events the universe has to offer: the explosion of a supergiant star in a Type II supernova event. After the collapse of the star’s core, the outgoing shock wave blows the star to pieces, both releasing and creating a host of elements. One of those is iron-60. While most of the iron in the universe is iron-56, a stable atom made up of 26 protons and 30 neutrons, iron-60 has four additional neutrons that make it an unstable radioactive isotope.
If a supernova occurs sufficiently close to our Solar System, it’s possible for some of the ejecta to make its way all the way to Earth. How might we detect these stellar shards? One way would be to look for traces of unique isotopes that could only have been produced by the explosion. A team of German scientists did just that. In a paper published earlier this month in the Proceedings of the National Academy of Sciences, they report the detection of iron-60 in biologically produced nanocrystals of magnetite in two sediment cores drilled from the Pacific Ocean.
Magnetite is an iron-rich mineral naturally attracted to a magnet just as a compass needle responds to Earth’s magnetic field. Magnetotactic bacteria, a group of bacteria that orient themselves along Earth’s magnetic field lines, contain specialized structures called magnetosomes, where they store tiny magnetic crystals – primarily as magnetite (or greigite, an iron sulfide) in long chains. It’s thought nature went to all this trouble to help the creatures find water with the optimal oxygen concentration for their survival and reproduction. Even after they’re dead, the bacteria continue to align like microscopic compass needles as they settle to the bottom of the ocean.
After the bacteria die, they decay and dissolve away, but the crystals are sturdy enough to be preserved as chains of magnetofossils that resemble beaded garlands on the family Christmas tree. Using a mass spectrometer, which teases one molecule from another with killer accuracy, the team detected “live” iron-60 atoms in the fossilized chains of magnetite crystals produced by the bacteria. Live meaning still fresh. Since the half-life of iron-60 is only 2.6 million years, any primordial iron-60 that seeded the Earth in its formation has long since disappeared. If you go digging around now and find iron-60, you’re likely looking at at a supernova as the smoking gun.
Co-authors Peter Ludwig and Shawn Bishop, along with the team, found that the supernova material arrived at Earth about 2.7 million years ago near the boundary of the Pleistocene and Pliocene epochs and rained down for all of 800,000 years before coming to an end around 1.7 million years ago. If ever a hard rain fell.
The peak concentration occurred about 2.2 million years ago, the same time our early human ancestors, Homo habilis, were chipping tools from stone. Did they witness the appearance of a spectacularly bright “new star” in the night sky? Assuming the supernova wasn’t obscured by cosmic dust, the sight must have brought our bipedal relations to their knees.
There’s even a possibility that an increase in cosmic rays from the event affected our atmosphere and climate and possibly led to a minor die-off at the time. Africa’s climate dried out and repeated cycles of glaciation became common as global temperatures continued their cooling trend from the Pliocene into the Pleistocene.
Cosmic rays, which are extremely fast-moving, high-energy protons and atomic nucleic, rip up molecules in the atmosphere and can even penetrate down to the surface during a nearby supernova explosion, within about 50 light years of the Sun. The high dose of radiation would put life at risk, while at the same time providing a surge in the number of mutations, one of the creative forces driving the diversity of life over the history of our planet. Life — always a story of taking the good with the bad.
The discovery of iron-60 further cements our connection to the universe at large. Indeed, bacteria munching on supernova ash adds a literal twist to the late Carl Sagan’s famous words: “The cosmos is within us. We are made of star-stuff.” Big or small, we owe our lives to the synthesis of elements within the bellies of stars.