With only an introductory course in science, it’s easy to think that scientists strictly follow the scientific method. They propose a new hypothesis, test that hypothesis, and after many years of hard work, either confirm or reject it. But science is often prone to chance. And when a surprise presents itself, the book titled “Scientific Method 101” often gets dropped in the trash. In short, science needs — and perhaps thrives on — stupid luck.
Take any scientific mission. Often designed to do one thing, a mission tends to open up a remarkable window on something unexpected. Now, NASA’s Kepler space telescope, designed to hunt for planets in our own galaxy, has helped measure an object much more distant and more massive than any of its detected planets: a black hole.
KA1858+4850 is a Seyfert galaxy with an active supermassive black hole feeding on nearby gas. It lies between the constellations Cygnus and Lyra approximately 100 million light-years away.
In 2012, Kepler provided a highly accurate light curve of the galaxy. But the team, led by Liuyi Pei from the University of California, Irvine, also relied on ground-based observations to compliment the Kepler data.
The trick is to look at how the galaxy’s light varies over time. The light first emitted from the accretion disk travels some distance before reaching a gas cloud, where it’s absorbed and re-emitted a short time later.
Measuring the time-delay between the two emitted points of light tells the size of the gap between the accretion disk and the gas cloud. And measuring the width of the emitted light from the gas cloud tells the velocity of the gas moving near the black hole (due to an effect known as Doppler broadening). Together, these two measurements allow astronomers to determine the mass of the supermassive black hole.
Pei and her colleagues measured a time delay of roughly 13 days, and a velocity of 770 kilometers per second. This allowed them to calculate a central black hole mass of roughly 8.06 million times the mass of the Sun.
The results have been published in the Astrophysical Journal and are available online.
A fascinating set of finds was announced today at the 225th meeting of the American Astronomical Society (AAS), currently underway this week in Seattle, Washington. A team of astronomers announced the discovery of eight new planets potentially orbiting their host stars in their respective habitable zones. Also dubbed the ‘Goldilocks Zone,’ this is the distance where — like the tempting fairytale porridge — it’s not too hot, and not too cold, but juuusst right for liquid water to exist.
And chasing the water is the name of the game when it comes to hunting for life on other worlds. Two of the discoveries announced, Kepler-438b and Kepler-442b, are especially intriguing, as they are the most comparable to the Earth size-wise of any exoplanets yet discovered.
“Most of these planets have a good chance of being rocky, like Earth,” said Guillermo Torres in a recent press release. Guillermo is the lead author in the study for the Harvard-Smithsonian Center for Astrophysics (CfA).
This also doubles the count of suspected terrestrial exo-worlds — planets with less than twice the diameter of the Earth — inferred to orbit in the habitable zone of their host stars.
Fans on exoplanet science will remember the announcement of the first prospective Earth-like world orbiting in the habitable zone of its host star, Kepler-186f announced just last year.
The Kepler Space Telescope looks for planets used a technique known as the transit method. If a planet is orbiting its host star along our line of sight, a small but measurable dip in the star’s brightness occurs. This has advantages over the radial velocity technique because it allows researchers to pin down the hidden planet’s orbit and size much more precisely. The transit method is biased, however, to planets close in to its host which happen to lie along our solar system-bound line of sight. Kepler may miss most exo-worlds inclined out of its view, but it overcomes this by staring at thousands of stars.
Launched in 2009, Kepler has wrapped up its primary phase of starring at a patch of sky along the plane of the Milky Way in the directions of the constellations of Cygnus, Lyra and Hercules, and is now in its extended K2 mission using the solar wind pressure as a 3rd ‘reaction wheel’ to carry out targeted searches along the ecliptic plane.
Both newly discovered worlds highlighted in today’s announcement orbit distant red dwarf stars. Kepler-438 b is estimated to be 12% larger in diameter than the Earth, and Kepler-442 b is estimated by the team to be 33% larger. These worlds have a 70% and 60% chance of being rocky, respectively. For comparison, Ice giant planet Uranus is 4 times the diameter of the Earth, and over 14 times more massive.
“We don’t know for sure whether any of the planets in our sample are truly habitable,” Said CfA co-researcher in the study David Kipping. All we can say is that they’re promising candidates.”
The idea of habitable worlds around red dwarf stars is a tantalizing one. These stars are fainter and cooler than our Sun, and 7.5% to 50% as massive. They also have two primary factors going for them: they’re the most common type of stars in the universe, and they have life spans measured in trillions of years, much longer than the current age of the universe. If life could go from muck to making microwave dinners here on Earth in just a few billion years, it’s had lots longer to do the same on worlds orbiting red dwarf stars.
There is, however, one catch: the habitable zone surrounding a red dwarf is much closer in to its host star, and any would-be planet is subject to frequent surface-sterilizing flares. Perhaps a world with a synchronous rotation might be spared this fate and feature a habitable hemisphere well inside the snow line permanently turned away from its host.
The team made these discoveries by sifting though Kepler’s preliminary finds that are termed KOI’s, or Kepler Objects of Interest. Though these potential discoveries were far too small to pin down their masses using the traditional method, the team employed a program named BLENDER to statically validate the finds. BLENDER has been employed before in concert with backup observations for extremely tiny exoplanet discoveries. Torres and Francois Fressin developed the BLENDER program, and it is currently run on the massive Pleiades supercomputer at NASA Ames.
It was also noted in today’s press conference that two KOIs awaiting validation — 5737.01 and 2194.03 — may also prove to be terrestrial worlds orbiting Sun-like stars that are possibly similar in size to the Earth.
But don’t plan on building an interstellar ark and heading off to these newly found worlds just yet. Kepler-438b sits 470 light years from Earth, and Kepler-442b is even farther away at 1,100 light years. And we’ll also add our usual caveat and caution that, from a distance, the planet Venus in our own solar system might look like a tempting vacation spot. (Spoiler alert: it’s not).
Still, these discoveries are fascinating finds and add to the growing menagerie of exoplanet systems. These will also serve as great follow up targets for TESS, Gaia and LSST survey, all set to add to our exoplanet knowledge in the coming decade.
And to think, I remember growing up as a child of the 1970s reading that exoplanet detections were soooo difficult that they might never occur in our lifetime… now, fast-forward to 2015, and we’re beginning to classify and characterize other brave new solar systems in the modern Age of Exoplanet Science.
-Looking to observe red dwarf stars with your backyard scope? Check out our handy list.
An actuator that was “behaving strangely” on the SpaceX Falcon 9’s upper stage caused a last minute scrub for Tuesday’s attempt to launch a Dragon capsule to the International Space Station, as well as the first try at an historic first stage landing on a floating platform in the Atlantic Ocean.
Need to investigate the upper stage Z actuator. Was behaving strangely. Next launch attempt on Friday at 5am.
SpaceX will try again on Friday, January 9, 2014 at 5:09 a.m. EST. Like today’s attempt, there will be only an instantaneous launch window available, meaning that the blastoff must proceed at that exact instant. Any delays due to technical issues or weather would force further delays.
This is the commercial space company’s fifth resupply mission to the ISS and the unmanned cargo freighter is loaded with more than 5,108 pounds (2317 kg) of scientific experiments, technology demonstrations, crew supplies, spare parts, food, water, clothing and assorted research gear for the space station.
The “experiment” that has attracted the most attention, however, is the attempt to land the first stage of the two-stage rocket on a floating platform in the Atlantic Ocean, approximately 320 km (200 miles) off the coast of Florida.
This is the first attempt at such a landing. SpaceX has conducted numerous successful soft landing tests on land, and done several touchdowns on the ocean’s surface.
Elon Musk has estimated the odds of success at the landing attempt at about 50% at best.
“It’s an experiment,” said Hans Koenigsmann, VP of Mission Assurance at SpaceX, speaking at a media briefing on Jan. 5 at the Kennedy Space Center. “There’s a certain likelihood that this will not work out right, that something will go wrong.” He also added that the landing on the off shore barge is just a secondary objective of SpaceX, not NASA.
With robotic spacecraft, we have explored, discovered and expanded our understanding of the Solar System and the Universe at large. Our five senses have long since reached their limits and cannot reveal the presence of new objects or properties without the assistance of extraordinary sensors and optics. Data is returned and is transformed into a format that humans can interpret.
Humans remain confined to low-Earth orbit and forty-three years have passed since humans last escaped the bonds of Earth’s gravity. NASA’s budget is divided between human endeavors and robotic and each year there is a struggle to find balance between development of software and hardware to launch humans or carry robotic surrogates. Year after year, humans continue to advance robotic capabilities and artificial intelligence (A.I.), and with each passing year, it becomes less clear how we will fit ourselves into the future exploration of the Solar System and beyond.
Is it a race in which we are unwittingly partaking that places us against our inventions? And like the aftermath of the Kasparov versus Deep Blue chess match, are we destined to accept a segregation as necessary? Allow robotics, with or without A.I., to do what they do best – explore space and other worlds?
Should we continue to find new ways and better ways to plug ourselves into our surrogates and appreciate with greater detail what they sense and touch? Consider how naturally our children engross themselves in games and virtual reality and how difficult it is to separate them from the technology. Or is this just a prelude and are we all antecedents of future Captain Kirks and Jean Luc Picards?
Approximately 55% of the NASA budget is in the realm of human spaceflight (HSF). This includes specific funds for Orion and SLS and half measures of supporting segments of the NASA agency, such as Cross-Agency Support, Construction and Maintenance. In contrast, appropriations for robotic missions – project development, operations, R&D – represent 39% of the budget.
The appropriation of funds has always favored human spaceflight, primarily because HSF requires costlier, heavier and more complex systems to maintain humans in the hostile environment of space. And while NASA budgets are not nearly weighted 2-to-1 in favor of human spaceflight, few would contest that the return on investment (ROI) is over 2-to-1 in favor of robotic driven exploration of space. And many would scoff at this ratio and counter that 3-to-1 or 4-to-1 is closer to the advantage robots have over humans.
Politics play a significantly bigger role in the choice of appropriations to HSF compared to robotic missions. The latter is distributed among smaller budget projects and operations and HSF has always involved large expensive programs lasting decades. The big programs attract the interest of public officials wanting to bring capital and jobs to their districts or states.
NASA appropriations are complicated further by a rift between the White House and Capitol Hill along party lines. The Democrat-controlled White House has favored robotics and the use of private enterprise to advance NASA while Republicans on the Hill have supported the big human spaceflight projects; further complications are due to political divisions over the issue of Climate Change. How the two parties treat NASA is the opposite to, at least, how the public perceives the party platforms – smaller government or more social programs, less spending and supporting private enterprise. This tug of war is clearly seen in the NASA budget pie chart.
The House reduced the White House request for NASA Space Technology by 15% while increasing the funds for Orion and SLS by 16%. Space Technology represents funds that NASA would use to develop the Asteroid Redirect Mission (ARM), which the Obama administration favors as a foundation for the first use of SLS as part of a human mission to an asteroid. In contrast, the House appropriated $100 million to the Europa mission concept. Due to the delays of Orion and SLS development and anemic funding of ARM, the first use of SLS could be to send a probe to Europa.
While HSF appropriations for Space Ops & Exploration (effectively HSF) increased ~6% – $300 million, NASA Science gained ~2% – $100 million over the 2014 appropriations; ultimately set by Capitol Hill legislators. The Planetary Society, which is the Science Mission Directorate’s (SMD) staunchest supporter, has expressed satisfaction that the Planetary Science budget has nearly reached their recommended $1.5 billion. However, the increase is delivered with the requirement that $100 million shall be used for Europa concept development and is also in contrast to cutbacks in other segments of the SMD budget.
Note also that NASA Education and Public Outreach (EPO) received a significant boost from Republican controlled Capital Hill. In addition to the specific funding – a 2% increase over 2014 and 34% over the White House request, there is $42 million given specifically to the Science Mission Directorate (SMD) for EPO. The Obama Adminstration has attempted to reduce NASA EPO in favor of a consolidated government approach to improve effectiveness and reduce government.
The drive to explore beyond Earth’s orbit and set foot on new worlds is not just a question of finances. In retrospect, it was not finances at all and our remaining shackles to Earth was a choice of vision. Today, politicians and administrators cannot proclaim ‘Let’s do it again! Let’s make a better Shuttle or a better Space Station.’ There is no choice but to go beyond Earth orbit, but where?
While the International Space Station program, led by NASA, now maintains a continued human presence in outer space, more people ask the question, ‘why aren’t we there yet?’ Why haven’t we stepped upon Mars or the Moon again, or anything other than Earth or floating in the void of low-Earth orbit. The answer now resides in museums and in the habitat orbiting the Earth every 90 minutes.
The retired Space Shuttle program and the International Space Station represent the funds expended on human spaceflight over the last 40 years, which is equivalent to the funds and the time necessary to send humans to Mars. Some would argue that the funds and time expended could have meant multiple human missions to Mars and maybe even a permanent presence. But the American human spaceflight program chose a less costly path, one more achievable – staying close to home.
Ultimately, the goal is Mars. Administrators at NASA and others have become comfortable with this proclamation. However, some would say that it is treated more as a resignation. Presidents have been defining the objectives of human spaceflight and then redefining them. The Moon, Lagrangian Points or asteroids as waypoints to eventually land humans on Mars. Partial plans and roadmaps have been constructed by NASA and now politicians have mandated a roadmap. And politicians forced continuation of development of a big rocket; one which needs a clear path to justify its cost to taxpayers. One does need a big rocket to get anywhere beyond low-Earth orbit. However, a cancellation of the Constellation program – to build the replacement for the Shuttle and a new human-rated spacecraft – has meant delays and even more cost overruns.
During the ten years that have transpired to replace the Space Shuttle, with at least five more years remaining, events beyond the control of NASA and the federal government have taken place. Private enterprise is developing several new approaches to lofting payloads to Earth orbit and beyond. More countries have taken on the challenge. Spearheading this activity, independent of NASA or Washington plans, has been Space Exploration Technologies Corporation (SpaceX).
SpaceX’s Falcon 9 and soon to be Falcon Heavy represent alternatives to what was originally envisioned in the Constellation program with Ares I and Ares V. Falcon Heavy will not have the capability of an Ares V but at roughly $100 million per flight versus $600 million per flight for what Ares V has become – the Space Launch System (SLS) – there are those that would argue that ‘time is up.’ NASA has taken too long and the cost of SLS is not justifiable now that private enterprise has developed something cheaper and done so faster. Is Falcon Nine and Heavy “better”, as in NASA administrator Dan Golden’s proclamation – ‘Faster, Better, Cheaper’? Is it better than SLS technology? Is it better simply because its cheaper for lifting each pound of payload? Is it better because it is arriving ready-to-use sooner than SLS?
Humans will always depend on robotic launch vehicles, capsules and habitats laden with technological wonders to make our spaceflight possible. However, once we step out beyond Earth orbit and onto other worlds, what shall we do? From Carl Sagan to Steve Squyres, NASA scientists have stated that a trained astronaut could do in just weeks what the Mars rovers have required years to accomplish. How long will this hold up and is it really true?
Since Chess Champion Garry Kasparov was defeated by IBM’s Deep Blue, there have been 8 two-year periods representing the doubling of transistors in integrated circuits. This is a factor of 256. Arguably, computers have grown 100 times more powerful in the 17 years. However, robotics is not just electronics. It is the confluence of several technologies that have steadily developed over the 40 years that Shuttle technology stood still and at least 20 years that Space Station designs were locked into technological choices. Advances in material science, nano-technology, electro-optics, and software development are equally important.
While human decision making has been capable of spinning its wheels and then making poor choices and logistical errors, the development of robotics altogether is a juggernaut. While appropriations for human spaceflight have always surpassed robotics, advances in robotics have been driven by government investments across numerous agencies and by private enterprise. The noted futurist and inventor Ray Kurzweil who predicts the arrival of the Singularity by around 2045 (his arrival date is not exact) has emphasized that the surpassing of human intellect by machines is inevitable due to the “The Law of Accelerating Returns”. Technological development is a juggernaut.
In the same year that NASA was founded, 1958, the term Singularity was first used by mathematician John von Neumann to describe the arrival of artificial intelligence that surpasses humans.
Unknowingly, this is the foot race that NASA has been in since its creation. The mechanisms and electronics that facilitated landing men on the surface of the Moon never stopped advancing. And in that time span, human decisions and plans for NASA never stopped vacillating or stop locking existing technology into designs; suffering delays and cost overruns before launching humans to space.
So are we destined to arrive on Mars and roam its surface like retired geologists and biologists wandering in the desert with a poking stick or rock hammer? Have we wasted too much time and has the window passed in which human exploration can make discoveries that robotics cannot accomplish faster, better and cheaper? Will Mars just become an art colony where humans can experience new sunrises and setting moons? Or will we segregate ourselves from our robotic surrogates and appreciate our limited skills and go forth into the Universe? Or will we mind meld with robotics and master our own biology just moments after taking our first feeble steps beyond the Earth?
Woah, is that ever close! The Hubble Space Telescope’s new picture of the Andromeda Galaxy makes us feel as though we’re hovering right above the iconic structure, which is visible with the naked eye from Earth under the right conditions.
Just to show you how awesome this close-up is, we’ve posted a picture below the jump showing what is the typical view of M31 in a more modest telescope.
“This ambitious photographic cartography of the Andromeda galaxy represents a new benchmark for precision studies of large spiral galaxies that dominate the universe’s population of over 100 billion galaxies,” stated the Space Telescope Science Institute (STScI), which operates the telescope.
“Never before have astronomers been able to see individual stars inside an external spiral galaxy over such a large contiguous area. Most of the stars in the universe live inside such majestic star cities, and this is the first data that reveal populations of stars in context to their home galaxy.”
Andromeda is about 2.5 million light-years from us and on a collision course with our galaxy. The image at the top of this story is actually not a single picture; it was assembled from an astounding 7,398 exposures taken over 411 individual pointings, according to STScI.
The image is so big, in fact, that there’s a zoomable version that was released separately so that you can get a better sense of how high-definition this view is. Dontcha wish you could take a light-travel ship and see this thing up close, for real?
The search for exoplanets is heating up, thanks to the deployment of space telescopes like Kepler and the development of new observation methods. In fact, over 1800 exoplanets have been discovered since the 1980s, with 850 discovered just last year. That’s quite the rate of progress, and Earth’s scientists have no intention of slowing down!
Hot on the heels of the Kepler mission and the ESA’s deployment of the Gaia space observatory last year, NASA is getting ready to launch TESS (the Transiting Exoplanet Survey Satellite). And to provide the launch services, NASA has turned to one of its favorite commercial space service providers – SpaceX.
The launch will take place in August 2017 from the Cape Canaveral Air Force Station in Florida, where it will be placed aboard a Falcon 9 v1.1 – a heavier version of the v 1.0 developed in 2013. Although NASA has contracted SpaceX to perform multiple cargo deliveries to the International Space Station, this will be only the second time that SpaceX has assisted the agency with the launch of a science satellite.
This past September, NASA also signed a lucrative contract with SpaceX worth $2.6 billion to fly astronauts and cargo to the International Space Station. As part of the Commercial Crew Program, SpaceX’s Falcon 9 and Dragon spacecraft were selected by NASA to help restore indigenous launch capability to the US.
The total cost for TESS is estimated at approximately $87 million, which will include launch services, payload integration, and tracking and maintenance of the spacecraft throughout the course of its three year mission.
As for the mission itself, that has been the focus of attention for many years. Since it was deployed in 2009, the Kepler spacecraft has yielded more and more data on distant planets, many of which are Earth-like and potentially habitable. But in 2013, two of four reaction wheels on Kepler failed and the telescope has lost its ability to precisely point toward stars. Even though it is now doing a modified mission to hunt for exoplanets, NASA and exoplanet enthusiasts have been excited by the prospect of sending up another exoplanet hunter, one which is even more ideally suited to the task.
Once deployed, TESS will spend the next three years scanning the nearest and brightest stars in our galaxy, looking for possible signs of transiting exoplanets. This will involve scanning nearby stars for what is known as a “light curve”, a phenomenon where the visual brightness of a star drops slightly due to the passage of a planet between the star and its observer.
By measuring the rate at which the star dims, scientists are able to estimate the size of the planet passing in front of it. Combined with measurements the star’s radial velocity, they are also able to determine the density and physical structure of the planet. Though it has some drawbacks, such as the fact that stars rarely pass directly in front of their host stars, it remains the most effective means of observing exoplanets to date.
In fact, as of 2014, this method became the most widely used for determining the presence of exoplanets beyond our Solar System. Compared to other methods – such as measuring a star’s radial velocity, direct imaging, the timing method, and microlensing – more planets have been detected using the transit method than all the other methods combined.
In addition to being able to spot planets by the comparatively simple method of measuring their light curve, the transit method also makes it possible to study the atmosphere of a transiting planet. Combined with the technique of measuring the parent star’s radial velocity, scientists are also able to measure a planet’s mass, density, and physical characteristics.
With TESS, it will be possible to study the mass, size, density and orbit of exoplanets. In the course of its three-year mission, TESS will be looking specifically for Earth-like and super-Earth candidates that exist within their parent star’s habitable zone.
This information will then be passed on to Earth-based telescopes and the James Webb Space Telescope – which will be launched in 2018 by NASA with assistance from the European and Canadian Space Agencies – for detailed characterization.
The TESS Mission is led by the Massachusetts Institute of Technology – who developed it with seed funding from Google – and is overseen by the Explorers Program at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
In the movie “Avatar”, we could tell at a glance that the alien moon Pandora was teeming with alien life. Here on Earth though, the most abundant life is not the plants and animals that we are familiar with. The most abundant life is simple and microscopic. There are 50 million bacterial organisms in a single gram of soil, and the world wide bacterial biomass exceeds that of all plants and animals. Microbes can grow in extreme environments of temperature, salinity, acidity, radiation, and pressure. The most likely form in which we will encounter life elsewhere in our solar system is microbial.
Astrobiologists need strategies for inferring the presence of alien microbial life or its fossilized remains. They need strategies for inferring the presence of alien life on the distant planets of other stars, which are too far away to explore with spacecraft in the foreseeable future. To do these things, they long for a definition of life, that would make it possible to reliably distinguish life from non-life.
Unfortunately, as we saw in the first installment of this series, despite enormous growth in our knowledge of living things, philosophers and scientists have been unable to produce such a definition. Astrobiologists get by as best they can with definitions that are partial, and that have exceptions. Their search is geared to the features of life on Earth, the only life we currently know.
In the first installment, we saw how the composition of terrestrial life influences the search for extraterrestrial life. Astrobiologists search for environments that once contained or currently contain liquid water, and that contain complex molecules based on carbon. Many scientists, however, view the essential features of life as having to do with its capacities instead of its composition.
In 1994, a NASA committee adopted a definition of life as a “self-sustaining chemical system capable of Darwinian evolution”, based on a suggestion by Carl Sagan. This definition contains two features, metabolism and evolution, that are typically mentioned in definitions of life.
Metabolism is the set of chemical processes by which living things actively use energy to maintain themselves, grow, and develop. According to the second law of thermodynamics, a system that doesn’t interact with its external environment will become more disorganized and uniform with time. Living things build and maintain their improbable, highly organized state because they harness sources of energy in their external environment to power their metabolism.
Plants and some bacteria use the energy of sunlight to manufacture larger organic molecules out of simpler subunits. These molecules store chemical energy that can later be extracted by other chemical reactions to power their metabolism. Animals and some bacteria consume plants or other animals as food. They break down complex organic molecules in their food into simpler ones, to extract their stored chemical energy. Some bacteria can use the energy contained in chemicals derived from non-living sources in the process of chemosynthesis.
In a 2014 article in Astrobiology, Lucas John Mix, a Harvard evolutionary biologist, referred to the metabolic definition of life as Haldane Life after the pioneering physiologist J. B. S. Haldane. The Haldane life definition has its problems. Tornadoes and vorticies like Jupiter’s Great Red Spot use environmental energy to sustain their orderly structure, but aren’t alive. Fire uses energy from its environment to sustain itself and grow, but isn’t alive either.
Despite its shortcomings, astrobiologists have used Haldane definition to devise experiments. The Viking Mars landers made the only attempt so far to directly test for extraterrestrial life, by detecting the supposed metabolic activities of Martian microbes. They assumed that Martian metabolism is chemically similar to its terrestrial counterpart.
One experiment sought to detect the metabolic breakdown of nutrients into simpler molecules to extract their energy. A second aimed to detect oxygen as a waste product of photosynthesis. A third tried to show the manufacture of complex organic molecules out of simpler subunits, which also occurs during photosynthesis. All three experiments seemed to give positive results, but many researchers believe that the detailed findings can be explained without biology, by chemical oxidizing agents in the soil.
Some of the Viking results remain controversial to this day. At the time, many researchers felt that the failure to find organic materials in Martian soil ruled out a biological interpretation of the metabolic results. The more recent finding that Martian soil actually does contain organic molecules that might have been destroyed by perchlorates during the Viking analysis, and that liquid water was once abundant on the surface of Mars lend new plausibility to the claim that Viking may have actually succeeded in detecting life. By themselves, though, the Viking results didn’t prove that life exists on Mars nor rule it out.
Most of the methane in Earth’s atmosphere is released by living organisms or their remains. Subterranean bacterial ecosystems that use chemosynthesis as a source of energy are common, and they produce methane as a metabolic waste product. Unfortunately, there are also non-biological geochemical processes that can produce methane. So, once more, Martian methane is frustratingly ambiguous as a sign of life.
Extrasolar planets orbiting other stars are far too distant to visit with spacecraft in the foreseeable future. Astrobiologists still hope to use the Haldane definition to search for life on them. With near future space telescopes, astronomers hope to learn the composition of the atmospheres of these planets by analyzing the spectrum of light wavelengths reflected or transmitted by their atmospheres. The James Webb Space Telescope scheduled for launch in 2018, will be the first to be useful in this project. Astrobiologists want to search for atmospheric biomarkers; gases that are metabolic waste products of living organisms.
Once more, this quest is guided by the only example of a life-bearing planet we currently have; Earth. About 21% of our home planet’s atmosphere is oxygen. This is surprising because oxygen is a highly reactive gas that tends to enter into chemical combinations with other substances. Free oxygen should quickly vanish from our air. It remains present because the loss is constantly being replaced by plants and bacteria that release it as a metabolic waste product of photosynthesis.
Traces of methane are present in Earth’s atmosphere because of chemosynthetic bacteria. Since methane and oxygen react with one another, neither would stay around for long unless living organisms were constantly replenishing the supply. Earth’s atmosphere also contains traces of other gases that are metabolic byproducts.
In general, living things use energy to maintain Earth’s atmosphere in a state far from the thermodynamic equilibrium it would reach without life. Astrobiologists would suspect any planet with an atmosphere in a similar state of harboring life. But, as for the other cases, it would be hard to completely rule out non-biological possibilities.
Besides metabolism, the NASA committee identified evolution as a fundamental ability of living things. For an evolutionary process to occur there must be a group of systems, where each one is capable of reliably reproducing itself. Despite the general reliability of reproduction, there must also be occasional random copying errors in the reproductive process so that the systems come to have differing traits. Finally, the systems must differ in their ability to survive and reproduce based on the benefits or liabilities of their distinctive traits in their environment. When this process is repeated over and over again down the generations, the traits of the systems will become better adapted to their environment. Very complex traits can sometimes evolve in a step-by-step fashion.
Mix named this the Darwin life definition, after the nineteenth century naturalist Charles Darwin, who formulated the theory of evolution. Like the Haldane definition, the Darwin life definition has important shortcomings. It has trouble including everything that we might think of as alive. Mules, for example, can’t reproduce, and so, by this definition, don’t count as being alive.
Despite such shortcomings, the Darwin life definition is critically important, both for scientists studying the origin of life and astrobiologists. The modern version of Darwin’s theory can explain how diverse and complex forms of life can evolve from some initial simple form. A theory of the origin of life is needed to explain how the initial simple form acquired the capacity to evolve in the first place.
The chemical systems or life forms found on other planets or moons in our solar system might be so simple that they are close to the boundary between life and non-life that the Darwin definition establishes. The definition might turn out to be vital to astrobiologists trying to decide whether a chemical system they have found really qualifies as a life form. Biologists still don’t know how life originated. If astrobiologists can find systems near the Darwin boundary, their findings may be pivotally important to understanding the origin of life.
Can astrobiologists use the Darwin definition to find and study extraterrestrial life? It’s unlikely that a visiting spacecraft could detect to process of evolution itself. But, it might be capable of detecting the molecular structures that living organisms need in order to take part in an evolutionary process. Philosopher Mark Bedau has proposed that a minimal system capable of undergoing evolution would need to have three things: 1) a chemical metabolic process, 2) a container, like a cell membrane, to establish the boundaries of the system, and 3) a chemical “program” capable of directing the metabolic activities.
Here on Earth, the chemical program is based on the genetic molecule DNA. Many origin-of-life theorists think that the genetic molecule of the earliest terrestrial life forms may have been the simpler molecule ribonucleic acid (RNA). The genetic program is important to an evolutionary process because it makes the reproductive copying process stable, with only occasional errors.
Both DNA and RNA are biopolymers; long chainlike molecules with many repeating subunits. The specific sequence of nucleotide base subunits in these molecules encodes the genetic information they carry. So that the molecule can encode all possible sequences of genetic information it must be possible for the subunits to occur in any order.
Steven Benner, a computational genomics researcher, believes that we may be able to develop spacecraft experiments to detect alien genetic biopolymers. He notes that DNA and RNA are very unusual biopolymers because changing the sequence in which their subunits occur doesn’t change their chemical properties. It is this unusual property that allows these molecules to be stable carriers of any possible genetic code sequence.
DNA and RNA are both polyelectrolytes; molecules with regularly repeating areas of negative electrical charge. Benner believes that this is what accounts for their remarkable stability. He thinks that any alien genetic biopolymer would also need to be a polyelectrolyte, and that chemical tests could be devised by which a spacecraft might detect such polyelectrolyte molecules. Finding the alien counterpart of DNA is a very exciting prospect, and another piece to the puzzle of identifying alien life.
In 1996 President Clinton, made a dramatic announcement of the possible discovery of life on Mars. Clinton’s speech was motivated by the findings of David McKay’s team with the Alan Hills meteorite. In fact, the McKay findings turned out to be just one piece to the larger puzzle of possible Martian life. Unless an alien someday ambles past our waiting cameras, the question of whether or not extraterrestrial life exists is unlikely to be settled by a single experiment or a sudden dramatic breakthrough. Philosophers and scientists don’t have a single, sure-fire definition of life. Astrobiologists consequently don’t have a single sure-fire test that will settle the issue. If simple forms of life do exist on Mars, or elsewhere in the solar system, it now seems likely that that fact will emerge gradually, based on many converging lines of evidence. We won’t really know what we’re looking for until we find it.
S. Tirard, M. Morange, and A. Lazcano, (2010), The definition of life: A brief history of an elusive scientific endeavor, Astrobiology, 10(10):1003-1009.
When you look at that image on the right, make sure to thank the STS-125 crew. And all the people who defended the idea of sending one last repair mission to the Hubble Space Telescope before the space shuttle was decommissioned.
That’s because the famous “Pillars of Creation” image taken in 1995 by Hubble just got a huge upgrade. Using a camera the astronauts installed in 2009, astronomers recently revisited the iconic image and got far more detail this time around. And please, do yourself a favor to click through and see the ethereal infrared image Hubble got at the same time.
Embedded in these Eagle Nebula towers, which are sometimes called elephant trunks, are stars under creation. And in a short span of 20 years, you can see how the stars are slowly blowing the pillars apart. This is leading some press officials to call the structures “pillars of destruction.” And astronomers can chart how everything is changing over time.
“I’m impressed by how transitory these structures are. They are actively being ablated away before our very eyes,” stated Paul Scowen of Arizona State University in Tempe, one of the astronomers who led the 1995 observations.
“These pillars represent a very dynamic, active process,” Scowen added. “The gas is not being passively heated up and gently wafting away into space. The gaseous pillars are actually getting ionized (a process by which electrons are stripped off of atoms) and heated up by radiation from the massive stars. And then they are being eroded by the stars’ strong winds (barrage of charged particles), which are sandblasting away the tops of these pillars.”
One large find from the two images showed a “narrow jet-like feature” that could have been emanating from a brand-new star. It’s been getting larger over the past two decades, moving more than 60 billion miles further into the universe.
The new images were presented at the American Astronomical Society meeting in Seattle this week.
Aiming to one day radically change the future of the rocket business, SpaceX CEO Elon Musk has a bold vision unlike any other in a historic attempt to recover and reuse rockets set for Jan. 6 with the goal of dramatically reducing the enormous costs of launching anything into space.
Towards the bold vision of rocket reusability, SpaceX dispatched the “autonomous spaceport drone ship” sailing at sea towards a point where Musk hopes it will serve as an ocean going landing platform for the first stage of his firm’s Falcon 9 rocket after it concludes its launch phase to the International Space Station (ISS).
“Drone spaceport ship heads to its hold position in the Atlantic to prepare for a rocket landing,” tweeted Musk today (Jan. 5) along with a photo of the drone ship underway (see above).
The history making and daring experimental landing is planned to take place in connection with the Tuesday, Jan. 6, liftoff of the Falcon 9 booster and Dragon cargo freighter bound for the ISS on a critical resupply mission for NASA.
No one has ever tried such a landing attempt before in the ocean says SpaceX. The company has conducted numerous successful soft landing tests on land. And several soft touchdowns on the ocean’s surface. But never before on a barge in the ocean.
The “autonomous spaceport drone ship” departed the port of Jacksonville, FL, on Saturday, heading to a point somewhere around 200 to 250 miles or so off the US East coast in a northeasterly direction coinciding with the flight path of the rocket.
The SpaceX Dragon CRS-5 mission is slated to blast off at 6:20 am EST, Tuesday, Jan. 6, 2015, atop the SpaceX Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.
The absolute overriding goal of the mission is to safely deliver NASA’s contracted payload to the ISS, emphasized Hans Koenigsmann, VP of Mission Assurance, SpaceX, at a media briefing today (Jan. 5) at the Kennedy Space Center. Landing on the off shore barge is just a secondary objective of SpaceX, not NASA, he repeated several times.
The Dragon CRS-5 spacecraft is loaded with over 5108 pounds (2317 kg) of scientific experiments, technology demonstrations, crew supplies, spare parts, food, water, clothing, and assorted research gear for the six person crew serving aboard the ISS.
Koenigsmann estimated the odds of success at the landing attempt at about 50% at best according to an estimate from Musk himself.
“It’s an experiment. There’s a certain likelihood that this will not work out right, that something will go wrong.”
The two stage Falcon 9 and Dragon stands 207.8 feet (63.3 meters) tall and is 12 feet in diameter. The first stage is powered by nine Merlin 1D engines that generate 1.3 million pounds of thrust at sea level and rises to 1.5 million pounds of thrust as the Falcon 9 climbs out of the atmosphere, according to a SpaceX fact sheet.
The first stage Merlins will fire for three minutes until the planned engine shutdown and main engine cutoff known as MECO, said Koenigsmann.
The rocket will be in space at an altitude of over 100 miles zooming upwards at 1300 m/s (nearly 1 mi/s).
Then, a single Merlin 1D will be commanded to re-fire for three separate times to stabilize and lower the rocket during the barge landing attempt.
Four hypersonic grid fins had been added to the first stage and placed in an X-wing configuration. They will be deployed only during the reentry attempt and will be used to roll, pitch, and yaw the rocket in concert with gamboling of the engines.
It will take about nine minutes from launch until the first stage reaches the barge, said Koenigsmann. That’s about the same time it takes for Dragon to reach orbit.
He added that, depending on the internet connectivity, SpaceX may or may not know the outcome in real time.
Here’s a description from SpaceX:
“To help stabilize the stage and to reduce its speed, SpaceX relights the engines for a series of three burns. The first burn—the boostback burn—adjusts the impact point of the vehicle and is followed by the supersonic retro propulsion burn that, along with the drag of the atmosphere, slows the vehicle’s speed from 1300 m/s to about 250 m/s. The final burn is the landing burn, during which the legs deploy and the vehicle’s speed is further.”
“To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that may sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky. During previous attempts, we could only expect a landing accuracy of within 10km. For this attempt, we’re targeting a landing accuracy of within 10 meters.”
CRS-5 marks the company’s fifth resupply mission to the ISS under a $1.6 Billion contract with NASA to deliver 20,000 kg (44,000 pounds) of cargo to the station during a dozen Dragon cargo spacecraft flights through 2016 under NASA’s Commercial Resupply Services (CRS) contract.
The cargo delivery is the entire point of the CRS-5 mission.
The weather odds have improved to 70% GO from 60% GO reported Major Perry Sweat, 45th Weather Squadron rep, USAF, at the briefing today at the Kennedy Space Center.
SpaceX is on track to rollout their Falcon 9 rocket carrying the Dragon cargo freighter this evening, Monday, Jan, 5, 2015 to launch pad 40 on a mission bound for the International Space Station (ISS) to deliver critical supplies.
The Dragon CRS-5 mission is slated to blast off at 6:20 a.m. EST, Tuesday, Jan. 6, 2015, atop the SpaceX Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.
The predawn launch should put on a spectacular sky show for spectators along the Florida space coast.
There is only an instantaneous launch window available, meaning that the blastoff must proceed at that exact instant. Any delays due to technical issues or weather would force a scrub until at least Friday, Jan. 9.
The launch has already been postponed several times, most recently from Dec. 19, 2014 when a static fire test of the first stage engines on Dec. 17 shut down prematurely.
A second static fire test of the SpaceX Falcon 9 successfully went the full duration of approximately 3 seconds and cleared the path for a liftoff attempt after the Christmas holidays.
The delay allowed the teams to recoup and recover and enjoy the festive holiday season.
“It was a good decision to postpone the launch until after the holidays,” said Hans Koenigsmann, VP of Mission Assurance, SpaceX, at a media briefing today at the Kennedy Space Center (KSC).
CRS-5 marks the company’s fifth resupply mission to the ISS under a $1.6 Billion contract with NASA to deliver 20,000 kg (44,000 pounds) of cargo to the station during a dozen Dragon cargo spacecraft flights through 2016 under NASA’s Commercial Resupply Services (CRS) contract
The weather odds have improved to 70% GO from 60% GO reported Major Perry Sweat, 45th Weather Squadron rep, USAF, at the briefing today at the Kennedy Space Center.
A frontal boundary has settled in over Central Florida. This front and its associated cloudiness will be very slow to move south of the Space Coast. With the clouds only slowly eroding overhead, the primary weather concern remains thick clouds, according to Sweat.
The unmanned cargo freighter is loaded with more than 5108 pounds (2317 kg) of scientific experiments, technology demonstrations, crew supplies, spare parts, food, water, clothing and assorted research gear for the space station.
The Dragon research experiments will support over 256 science and research investigations for the six person space station crews on Expeditions 42 and 43.
Among the payloads is the Cloud-Aerosol Transport System (CATS), a remote-sensing laser instrument to measure clouds and the location and distribution of pollution, dust, smoke, and other particulates and aerosols in the atmosphere.
Assuming all goes well, Dragon will rendezvous at the ISS on Thursday, Jan. 8, for grappling and berthing by the ISS astronauts maneuvering the 57 foot-long (17 meter-long) Canadian built robotic arm.
The SpaceX CRS-5 launch is the first cargo launch to the ISS since the doomed Orbital Sciences Antares/Cygnus launch ended in catastrophe on Oct. 28.
With Antares launches on indefinite hold, the US supply train to the ISS is now wholly dependent on SpaceX.
Orbital Sciences has now contracted United Launch Alliance (ULA) to launch the firms Cygnus cargo freighter to the ISS by late 2015 on an Atlas V rocket.
A secondary objective of SpaceX is to attempt to recover the Falcon 9 first stage on an off shore barge.
NASA Television live launch coverage begins at 5 a.m. EST on Jan. 6.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.