The Sagittarius constellation, as imaged by the Hubble Space Telescope. Credit: IAU/NASA/ESA/HST
In May of 2016, the IAU Executive Committee approved of the creation of a special task force known as the Working Group on Star Names (WGSN). Composed of an international group of experts in astronomy, astronomical history, and cultural astronomy, the purpose of the WGSN is to formalize the names of stars that have been used colloquially for centuries.
This has involved sorting through the texts and traditions of many of the world’s cultures, seeking out unique names and standardizing their spelling. And after about six months, their labors have led to the creation of a new catalog of IAU star names, the first 227 of which were recently published on the IAU website.
This initiative grew out of the IAU’s Division C – Education, Outreach and Heritage group, which is responsible for engaging the public in all matters of astronomy. Their overall purpose is to establish IAU guidelines for the proposal and adoption of star names, to search historical and cultural literature for them, to adopt unique names that have scientific and historical value, and to publish and disseminate official IAU star name catalogs.
In this respect, the WGSN is breaking with standard astronomical practice. For many years, astronomers have named the stars they have been responsible for studying using an alphanumerical designation. These designations are seen as immensely practical, since star catalogs typically contain thousands, millions or even billions of objects. If there’s one thing the observable Universe has no shortage of, its stars!
However, many of these stars already have traditional names which may have fallen into disuse. The WGSN’s job, therefore, is to find commonly-used, traditional names of stars and determine which ones shall be officially used. In addition to preserving humanity’s astronomical heritage, this process is also intended to make sure that there is standardization in terms of naming and spelling, so as to prevent confusion.
What’s more, with the discovery of exoplanets becoming a regular thing nowadays, the IAU hopes to engage the international astronomical community in naming these planets according to their stars traditional name (if they have one). As Eric Mamajek, the chair and organiser of the WGSN, explained their purpose:
“Since the IAU is already adopting names for exoplanets and their host stars, it has been seen as necessary to catalogue the names for stars in common use from the past, and to clarify which ones will be official from now on.”
Artist’s impression of a system of exoplanets orbiting a low mass, red dwarf star. Credit: NASA/JPL
For instance, it can certainly be said that HD 40307 g – an exoplanet candidate that orbits within the habitable zone of its K-type star some 42 light years away – has a pretty clunky name. But what if, upon searching through various historical sources, the WGSN found that this star was traditionally known as “mikiya” (eagle) to the Hausa people of northern Nigeria? Then this super-Earth could be named Mikiya g (or Mikiya Prime). Doesn’t that sound cooler?
And this effort is hardly without precedent. As Mamajek explained, the IAU engaged in a very similar effort decades ago with respect to the constellations:
“A similar effort was conducted early in the history of the IAU, in the 1920s, when the 88 modern constellations were clarified from historical literature, and their boundaries, names, spellings, and abbreviations were delineated for common use in the international astronomical community. Many of these names are used today by astronomers for designations of variable stars, names for new dwarf galaxies and bright X-ray sources, and other astronomical objects.”
Much like the constellations, the new star names are largely rooted in astronomical and cultural traditions of the Ancient Near East and Greece. Their names are rendered in Greek, Latin or Aabic, and have likely undergone little change since the Renaissance, a time where the production of star catalogs, atlases and globes experienced an explosion in growth.
Others, however, are more recent in origin, having been discovered and named in the 19th or 20th centuries. The IAU is looking to locate as many ancient names as possible, then incorporate them into an official IAU-approved database with more modern stars. These databases will be made available for use by astronomers, navigators and the general public.
In accordance with WGSN guildines, shorter, one-word names are preferred, as are those that have their roots in astronomical, cultural or natural world heritage. The 227 names that have been released include 209 recently approved names by the WGSN, plus the 18 stars that the IAU Executive Committee Working Group for Public Naming of Planets and Planetary Satellites approved of in December 2015.
Among those names that were approved are Proxima Centauri (which is orbited by the closest exoplanet to Earth, Proxima b), as well as Rigil Kentaurus (the ancient name for Alpha Centauri), Algieba (Gamma-1 Leonis), Hamal (Alpha Arietis), and Muscida (Omicron Ursae Majoris).
This number is expected to grow, as the WGSN continues to revive ancient stellar names and add new ones that are suggested by the international astronomical community.
Image of the "Face of Mars" by the Mars Reconnaissance Orbiter, with the Viking 1 image inset (bottom right). Credit: NASA/JPL
The surface of Mars has been the subject of fascination for centuries. Even sinceGiovanni Schiaparelli first announced that he had observed the “Martian Canals” in 1877, the Red Planet has been a source of endless speculation. Even today, crystal-clear images sent directly from the surface by rovers are still the subject of pareidolia – where people see familiar patterns in random features.
Nowhere has this tendency of seeing what we want to see on the surface of Mars been made more clean than with the Cydonia region. Located in the northern hemisphere, this region of Mars is known for its many interesting land forms. The most famous of these is the “Face of Mars”, which has attracted immense scientific and popular curiosity over the past few decades.
Location:
The area called Cydonia is in the northern hemisphere of Mars, in between the heavily cratered regions of the south (the Arabia Terra highlands) and the smooth plains to the north (Acidalia Planitia). The area includes the regions of flat-topped mesa-like featured (“Cydonia Mensae”), a region of small hills or knobs, (“Cydonia Colles”) and a complex of intersecting valleys (“Cydonia Labyrinthus”).
Image of the Cydonia region under infrared light taken by the Viking 1 orbiter. Credit: NASA/JPL
Because of its geographical location, it is possible that Cydonia was once a coastal plain region, billions of years ago when the northern hemisphere of Mars is believed to have been covered with water. The name – like many featured on Mars – is drawn from classical antiquity; in this case, from the historic city-state of Kydonia, which was located on the island of Crete.
Exploration:
Cydonia was first photographed by the Viking 1 and 2 orbiters. Between the two, eighteen images were taken of the region, all of which were of limited resolution. Of these, only five were considered suitable for studying surface features. Because of their limited quality, a particular mesa resembled a humanoid face (see below).
It would be another 20 years before other spacecraft photographed the region as they conducted observations of Mars. These included NASA’s Mars Global Surveyor, which orbited Mars from 1997 to 2006; the Mars Reconnaissance Orbiter (MRO), which reached the planet in 2006 and is still in operation; and the ESA’s Mars Express probe – which has been in orbit since 2003.
Each of these missions provided images of Cydonia which were much better in terms of resolution and debunked the existence of an artificial “Face of Mars” feature. After analyzing images taken by the Mars Global Surveyor, NASA declared that “a detailed analysis of multiple images of this feature reveals a natural looking Martian hill whose illusory face-like appearance depends on the viewing angle and angle of illumination”.
A section of the Cydonia region, taken by the Viking 1 orbiter and released on July 25, 1976. Credit: NASA/JPL
Notable Features:
As already noted, Cydonia’s best known feature is the famous “Face of Mars“. This 2 km long mesa, which was first photographed by the Viking 1 orbiter on July 25th, 1976, initially was thought to resemble a human face. At the time, the NASA science team dismissed this as a “trick of light and shadow”. But a second image, acquired 35 orbits later at a different angle, confirmed the existence of the “Face of Mars”.
Vincent DiPietro and Gregory Molenaar, two computer engineers at NASA’s Goddard Space Flight Center, independently discovered this image while searching through the NASA archives. From 1982 onward, these images would lead widespread speculation about what could have caused it, and fueled interest in the possible existence of a civilization on Mars.
In addition, DiPeitro and Molenaar noticed several mountains near the “Face” that had angular peaks, which they referred to as “pyramids“. One in particular, a 500 meter-tall mountain located to the south-west, was especially geometric in shape. Richard Hoagland, a famous conspiracy theorist, dubbed it the “D&M Pyramid” (in honor of DiPietro and Molenaar), a name which stuck.
Last, but not least, there is also the area to the north of the “Face” that was dubbed “the city”, because of its supposed resemblance to a series of monuments. These consisted predominately of more ‘pyramids’ that are arranged in a circular pattern around a series of smaller rocky features, known as the “City Square” (see below).
Mosaic created from images taken by the Viking orbiter, showing landforms in Cydonia with popular, informal names. Credit: NASA/JPL
Later images provided by the Mars Global Surveyor, the MRO and the Mars Express all resolved these features with far greater accuracy, showing them to be natural features with no evidence of construction of manipulation. In all cases, psychologists indicated that the desire to see familiar shapes and patterns was an example of pareidolia.
As for the Cydonia region, future missions to the planet may take an interest in exploring it further. However, this will most likely to get a better understanding of the regions past and see it was indeed a coastal region at one time. There will be NO attempts to search for signs of ziggurats, pyramids, ancient sarcophagi, or any other indications of a lost civilization.
Artist's impression of the ExoMars Schiaparelli lander passing into Mars' atmosphere. Credit: ESA
The European Space Agency (ESA) and Roscomos (the Russian federal space agency) had high hopes for the Schiaparelli lander, which crashed on the surface of Mars on October 19th. As part of the ExoMars program, its purpose was to test the technologies that will be used to deploy a rover to the Red Planet in 2020.
However, investigators are making progress towards determining what went wrong during the lander’s descent. Based on their most recent findings, they concluded that an anomaly took place with an on-board instrument that led to the lander detaching from its parachute and backshell prematurely. This ultimately caused it to land hard and be destroyed.
According to investigators, the data retrieved from the lander indicates that for the most part, Schiaparelli was functioning normally before it crashed. This included the parachute deploying once it had reached an altitude of 12 km and achieved a speed of 1730 km/h. When it reached an altitude of 7.8 km, the lander’s heatshield was released, and it radar altimeter provided accurate data to the lander’s on-board guidance, navigation and control system.
Schiaparelli lander descent sequence. According to their investigation, the ESA has determined that an error led the parachute and backshell to be jettisoned prematurely, causing the lander to crash. Credit: ESA/ATG medialab
All of this happened according to plan and did not contribute to the fatal crash. However, an anomaly then took place with the Inertial Measurement Unit (IMU), which is there to measure the rotation rates of the vehicle. Apparently, the IMU experienced saturation shortly after the parachute was deployed, causing it to persist for one second longer than required.
This error was then fed to the navigation system, which caused it to generate an estimate altitude that was below Mars’ actual ground level. In essence, the lander thought it was closer to the ground than it actually was. As such, the the parachute and backshell of the Entry and Descent Module (EDM) were jettisoned and the braking thrusters fired prematurely – at an altitude of 3.7 km instead of 1.2 km, as planned.
This briefest of errors caused the lander to free-fall for one second longer than it was supposed to, causing it to land hard and be destroyed. The investigators have confirmed this assessment using multiple computer simulations, all of which indicate that the IMU error was responsible. However, this is still a tentative conclusion that awaits final confirmation from the agency.
Artist’s impression of the Schiaparelli lander on Mars. Credit: ESA/ATG medialab
As David Parker, the ESA’s Director of Human Spaceflight and Robotic Exploration, said on on Wednesday, Nov. 23rd in a ESA press release:
“This is still a very preliminary conclusion of our technical investigations. The full picture will be provided in early 2017 by the future report of an external independent inquiry board, which is now being set up, as requested by ESA’s Director General, under the chairmanship of ESA’s Inspector General. But we will have learned much from Schiaparelli that will directly contribute to the second ExoMars mission being developed with our international partners for launch in 2020.”
In other words, this accident has not deterred the ESA and Roscosmos from pursuing the next stage in the ExoMars program – which is the deployment of the ExoMars rover in 2020. When it reaches Mars in 2021, the rover will be capable of navigating autonomously across the surface, using a on-board laboratory suite to search for signs of biological life, both past and present.
In the meantime, data retrieved from Schiaparelli’s other instruments is still being analyzed, as well as information from orbiters that observed the lander’s descent. It is hoped that this will shed further light on the accident, as well as salvage something from the mission. The Trace Gas Orbiter is also starting its first series of observations since it made its arrival in orbit on Oct. 19th, and will reach its operational orbit towards the end of 2017.
Blastoff of revolutionary NASA/NOAA GOES-R weather satellite on ULA Atlas V on Nov. 19, 2016 - as seen from remote camera at Space Launch Complex 41 (SLC-41) on Cape Canaveral Air Force Station, Florida. GOES-R will deliver a quantum leap in America’s weather forecasting capabilities. Credit: Ken Kremer/kenkremer.com
Blastoff of revolutionary NASA/NOAA GOES-R weather satellite on ULA Atlas V on Nov. 19, 2016 – as seen from remote camera at Space Launch Complex 41 (SLC-41) on Cape Canaveral Air Force Station, Florida. GOES-R will deliver a quantum leap in America’s weather forecasting capabilities. Credit: Ken Kremer/kenkremer.com
KENNEDY SPACE CENTER, FL – The fire and fury of the mighty ULA Atlas V got the gorgeous NASA/NOAA GOES-R weather observatory to geostationary orbit just days ago – as a ‘Thanksgiving’ present to all the people of Earth through the combined efforts of the government/industry/university science and engineering teams of hard working folks who made it possible.
Check out this dazzling photo and video gallery from myself and several space journalist colleagues showing how GOES got going – from prelaunch to launch atop a United Launch Alliance Atlas V rocket from Space Launch Complex 41 (SLC-41) Cape Canaveral Air Force Station at 6:42 p.m. EST in the evening on Saturday, Nov. 19, 2016.
Three and a half hours after liftoff, the bus sized spacecraft successfully separated from the Atlas Centaur upper stage and deployed its life giving solar arrays.
ULA Atlas V rocket and GOES-R weather observatory streak to orbit from launch pad 41 at Cape Canaveral, Florida. Credit: Julian Leek
GOES-R is the most advanced and powerful weather observatory ever built and will bring about a ‘quantum leap’ in weather forecasting.
It’s dramatic new imagery will show the weather in real time enabling critical life and property forecasting, help pinpoint evacuation zones and also save people’s lives in impacted areas of severe weather including hurricanes and tornadoes.
Here’s a pair of beautiful launch videos from space colleague Jeff Seibert and myself:
Video Caption: 5 views from the launch of the NOAA/NASA GOES-R weather satellite on 11/19/2016 from Pad 41 CCAFS on a ULA Atlas. Credit: Jeff Seibert
Video Caption: Launch of the NOAA/NASA GOES-R weather observatory satellite on Nov. 19, 2016 from pad 41 on Cape Canaveral Air Force Station on a ULA Atlas V rocket – as seen in this remote video taken at the pad. Credit: Ken Kremer/kenkremer.com
GOES-R is the first in a new series of revolutionary NASA/NOAA geostationary weather satellites that will soon lead to more accurate and timely forecasts, watches and warnings for the Earth’s Western Hemisphere when it becomes fully operational in about a year.
Ignition of ULA Atlas V rocket and GOES-R weather observatory at launch pad 41 at Cape Canaveral, Florida. Credit: Julian Leek
GOES-R, which stands for Geostationary Operational Environmental Satellite – R Series – is a new and advanced transformational weather satellite that will vastly enhance the quality, speed and accuracy of weather forecasting available to forecasters for Earth’s Western Hemisphere.
The 11,000 pound satellite was built by prime contractor Lockheed Martin and is the first of a quartet of four identical satellites – comprising GOES-R, S, T, and U – at an overall cost of about $11 Billion. This will keep the GOES satellite system operational through 2036.
Blastoff of revolutionary NASA/NOAA GOES-R weather satellite on ULA Atlas V on Nov. 19, 2016 – as seen from remote camera at Space Launch Complex 41 (SLC-41) on Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer/kenkremer.com
The science suite includes the Advanced Baseline Imager (ABI) built by Harris Corporation, the Geostationary Lightning Mapper (GLM) built by Lockheed Martin, Solar Ultraviolet Imager (SUVI), Extreme Ultraviolet and X-Ray Irradiance Sensors (EXIS), Space Environment In-Situ Suite (SEISS), and the Magnetometer (MAG).
ABI is the primary instrument and will collect 3 times more spectral data with 4 times greater resolution and scans 5 times faster than ever before – via the primary Advanced Baseline Imager (ABI) instrument – compared to the current GOES satellites.
Atlas V and GOES-R aloft after Nov. 19, 2016 liftoff of the powerful NASA/NOAA weather observatory on ULA Atlas V from pad 41 on Cape Canaveral Air Force Station, Florida – as seen from the VAB roof. Credit: Ken Kremer/kenkremer.com
GOES-R launched on the massively powerful Atlas V 541 configuration vehicle, augmented by four solid rocket boosters on the first stage.
The payload fairing is 5 meters (16.4 feet) in diameter. The first stage is powered by the Russian built duel nozzle RD AMROSS RD-180 engine. And the Centaur upper stage is powered by a single-engine Aerojet Rocketdyne RL10C engine.
This was only the fourth Atlas V launch employing the 541 configuration.
ULA Atlas V rocket and GOES-R weather observatory at launch pad 41 at Cape Canaveral, Florida. Credit: Dawn Leek Taylor
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Track mobile used to push ULS Atlas V and NASA/NOAA GOES-R to pad 41 from VIF processing facility. Credit: Lane HermannLaunch of NASA/NOAA GOES-R weather observatory on ULA Atlas V on Nov. 19, 2016 from pad 41 on Cape Canaveral Air Force Station, Florida, as seen from Playalinda beach. Credit: Jillian LaudickAtlas V/GOES-R launch as seen rising over neighbor houses in Titusville, Florida on Nov. 19, 2016. Credit: Melissa BaylesAtlas V rocket and GOES-R nighttime launch soars over the swimming pool at the Quality Inn Kennedy Space Center in Titusville, Florida on Nov. 19, 2016. Credit: Wesley BaskinThe NASA/NOAA GOES-R (Geostationary Operational Environmental Satellite – R Series) being processed at Astrotech Space Operations, in Titusville, FL, in advance of launch on a ULA Atlas V on Nov. 19, 2016. GOES-R will be America’s most advanced weather satellite. Credit: Ken Kremer/kenkremer.com
We’ve covered the Fermi Paradox many times over several articles on Universe Today. This is the idea that the Universe is huge, and old, and the ingredients of life are everywhere. Life could and should have have appeared many times across the galaxy, but it’s really strange that we haven’t found any evidence for them yet.
Today, CERN announced that the LHCb experiment had revealed the existence of two new baryon subatomic particles. Credit: CERN/LHC/GridPP
What if it were possible to observe the fundamental building blocks upon which the Universe is based? Not a problem! All you would need is a massive particle accelerator, an underground facility large enough to cross a border between two countries, and the ability to accelerate particles to the point where they annihilate each other – releasing energy and mass which you could then observe with a series of special monitors.
Well, as luck would have it, such a facility already exists, and is known as the CERN Large Hardron Collider (LHC), also known as the CERN Particle Accelerator. Measuring roughly 27 kilometers in circumference and located deep beneath the surface near Geneva, Switzerland, it is the largest particle accelerator in the world. And since CERN flipped the switch, the LHC has shed some serious light on some deeper mysteries of the Universe.
Purpose:
Colliders, by definition, are a type of a particle accelerator that rely on two directed beams of particles. Particles are accelerated in these instruments to very high kinetic energies and then made to collide with each other. The byproducts of these collisions are then analyzed by scientists in order ascertain the structure of the subatomic world and the laws which govern it.
The Large Hadron Collider is the most powerful particle accelerator in the world. Credit: CERN
The purpose of colliders is to simulate the kind of high-energy collisions to produce particle byproducts that would otherwise not exist in nature. What’s more, these sorts of particle byproducts decay after very short period of time, and are are therefor difficult or near-impossible to study under normal conditions.
The term hadron refers to composite particles composed of quarks that are held together by the strong nuclear force, one of the four forces governing particle interaction (the others being weak nuclear force, electromagnetism and gravity). The best-known hadrons are baryons – protons and neutrons – but also include mesons and unstable particles composed of one quark and one antiquark.
Design:
The LHC operates by accelerating two beams of “hadrons” – either protons or lead ions – in opposite directions around its circular apparatus. The hadrons then collide after they’ve achieved very high levels of energy, and the resulting particles are analyzed and studied. It is the largest high-energy accelerator in the world, measuring 27 km (17 mi) in circumference and at a depth of 50 to 175 m (164 to 574 ft).
The tunnel which houses the collider is 3.8-meters (12 ft) wide, and was previously used to house the Large Electron-Positron Collider (which operated between 1989 and 2000). This tunnel contains two adjacent parallel beamlines that intersect at four points, each containing a beam that travels in opposite directions around the ring. The beam is controlled by 1,232 dipole magnets while 392 quadrupole magnets are used to keep the beams focused.
Superconducting quadrupole electromagnets are used to direct the beams to four intersection points, where interactions between accelerated protons will take place.Credit: Wikipedia Commons/gamsiz
About 10,000 superconducting magnets are used in total, which are kept at an operational temperature of -271.25 °C (-456.25 °F) – which is just shy of absolute zero – by approximately 96 tonnes of liquid helium-4. This also makes the LHC the largest cryogenic facility in the world.
When conducting proton collisions, the process begins with the linear particle accelerator (LINAC 2). After the LINAC 2 increases the energy of the protons, these particles are then injected into the Proton Synchrotron Booster (PSB), which accelerates them to high speeds.
They are then injected into the Proton Synchrotron (PS), and then onto the Super Proton Synchrtron (SPS), where they are sped up even further before being injected into the main accelerator. Once there, the proton bunches are accumulated and accelerated to their peak energy over a period of 20 minutes. Last, they are circulated for a period of 5 to 24 hours, during which time collisions occur at the four intersection points.
During shorter running periods, heavy-ion collisions (typically lead ions) are included the program. The lead ions are first accelerated by the linear accelerator LINAC 3, and the Low Energy Ion Ring (LEIR) is used as an ion storage and cooler unit. The ions are then further accelerated by the PS and SPS before being injected into LHC ring.
While protons and lead ions are being collided, seven detectors are used to scan for their byproducts. These include the A Toroidal LHC ApparatuS (ATLAS) experiment and the Compact Muon Solenoid (CMS), which are both general purpose detectors designed to see many different types of subatomic particles.
Then there are the more specific A Large Ion Collider Experiment (ALICE) and Large Hadron Collider beauty (LHCb) detectors. Whereas ALICE is a heavy-ion detector that studies strongly-interacting matter at extreme energy densities, the LHCb records the decay of particles and attempts to filter b and anti-b quarks from the products of their decay.
CERN, which stands for Conseil Européen pour la Recherche Nucléaire (or European Council for Nuclear Research in English) was established on Sept 29th, 1954, by twelve western European signatory nations. The council’s main purpose was to oversee the creation of a particle physics laboratory in Geneva where nuclear studies would be conducted.
Illustration showing the byproducts of lead ion collisions, as monitored by the ATLAS detector. Credit: CERN
Soon after its creation, the laboratory went beyond this and began conducting high-energy physics research as well. It has also grown to include twenty European member states: France, Switzerland, Germany, Belgium, the Netherlands, Denmark, Norway, Sweden, Finland, Spain, Portugal, Greece, Italy, the UK, Poland, Hungary, the Czech Republic, Slovakia, Bulgaria and Israel.
Construction of the LHC was approved in 1995 and was initially intended to be completed by 2005. However, cost overruns, budget cuts, and various engineering difficulties pushed the completion date to April of 2007. The LHC first went online on September 10th, 2008, but initial testing was delayed for 14 months following an accident that caused extensive damage to many of the collider’s key components (such as the superconducting magnets).
On November 20th, 2009, the LHC was brought back online and its First Run ran from 2010 to 2013. During this run, it collided two opposing particle beams of protons and lead nuclei at energies of 4 teraelectronvolts (4 TeV) and 2.76 TeV per nucleon, respectively. The main purpose of the LHC is to recreate conditions just after the Big Bang when collisions between high-energy particles was taking place.
Major Discoveries:
During its First Run, the LHCs discoveries included a particle thought to be the long sought-after Higgs Boson, which was announced on July 4th, 2012. This particle, which gives other particles mass, is a key part of the Standard Model of physics. Due to its high mass and elusive nature, the existence of this particle was based solely in theory and had never been previously observed.
The discovery of the Higgs Boson and the ongoing operation of the LHC has also allowed researchers to investigate physics beyond the Standard Model. This has included tests concerning supersymmetry theory. The results show that certain types of particle decay are less common than some forms of supersymmetry predict, but could still match the predictions of other versions of supersymmetry theory.
In May of 2011, it was reported that quark–gluon plasma (theoretically, the densest matter besides black holes) had been created in the LHC. On November 19th, 2014, the LHCb experiment announced the discovery of two new heavy subatomic particles, both of which were baryons composed of one bottom, one down, and one strange quark. The LHCb collaboration also observed multiple exotic hadrons during the first run, possibly pentaquarks or tetraquarks.
Since 2015, the LHC has been conducting its Second Run. In that time, it has been dedicated to confirming the detection of the Higgs Boson, and making further investigations into supersymmetry theory and the existence of exotic particles at higher-energy levels.
The ATLAS detector, one of two general-purpose detectors at the Large Hadron Collider (LHC). Credit: CERN
In the coming years, the LHC is scheduled for a series of upgrades to ensure that it does not suffer from diminished returns. In 2017-18, the LHC is scheduled to undergo an upgrade that will increase its collision energy to 14 TeV. In addition, after 2022, the ATLAS detector is to receive an upgrade designed to increase the likelihood of it detecting rare processes, known as the High Luminosity LHC.
The collaborative research effort known as the LHC Accelerator Research Program (LARP) is currently conducting research into how to upgrade the LHC further. Foremost among these are increases in the beam current and the modification of the two high-luminosity interaction regions, and the ATLAS and CMS detectors.
Who knows what the LHC will discover between now and the day when they finally turn the power off? With luck, it will shed more light on the deeper mysteries of the Universe, which could include the deep structure of space and time, the intersection of quantum mechanics and general relativity, the relationship between matter and antimatter, and the existence of “Dark Matter”.
Illustration of Jupiter and the Galilean satellites. Credit: NASA
Welcome back to our series on Settling the Solar System! Today, we take a look at the largest of the Jovian Moons – Io, Europa, Ganymede and Callisto!
In 1610, Galileo Galilei became the first astronomer to discover the large moons of Jupiter, using a telescope of his own design. As time passed, these moons – Io, Europa, Ganymede, and Callisto – would collectively come to be referred to as the Galilean Moons, in honor of their discoverer. And with the birth of space exploration, what we’ve come to know about these satellites has fascinated and inspired us.
For example, ever since the Pioneer and Voyager probes passed through the system decades ago, scientists have suspected that moons like Europa might be our best bet for finding life in our Solar System beyond Earth. And because of the presence of water ice, interior oceans, minerals, and organic molecules, it has been speculated that humanity might establish colonies on one or more of these worlds someday.
Examples in Fiction:
The concept of a colonized Jovian system is featured in many science fiction publications. For instance, Robert A. Heinlein’s novel Farmer in the Sky (1953) centers on a teenage boy and his family moving to Ganymede. The moon is in the process of being terraformed in the story, and farmers are being recruited to help turn it into an agricultural colony.
Cover of Arthur C. Clarke’s 1982 novel, 2010: Odyssey Two. Credit: Public Domain
In the course of the story, it is mentioned that there are also efforts to introduce an atmosphere on Callisto. Many of his Heinlein’s other novels include passing mentions of a colony on Ganymede, including The Rolling Stones (1952), Double Star (1956), I Will Fear No Evil (1970), and the posthumously-written Variable Star (2006).
In 1954, Poul Anderson published a novella titled The Snows of Ganymede(1954). In this story, a party of terraformers visits a settlement on Ganymede called X, which was established two centuries earlier by a group of American religious fanatics.
In Arthur C. Clarke’s Space Odyssey series, the moon of Europa plays a central role. In 2010: Odyssey Two(1982) an ancient race of advanced aliens are turning the moon into a habitable body by converting Jupiter into a second sun. The warmth of this dwarf star (Lucifer) causes the surface ice on Europa to melt, and the life forms that are evolving underneath are able to emerge.
In 2061: Odyssey Three, Clarke also mentions how Lucifer’s warmth has caused Ganymede’s surface to partially sublimate, creating a large equatorial lake. Isaac Asimov also used the moons of Jupiter in his stories. In the short stories “Not Final!” (1941) and “Victory ‘Unintentional'” (1942), a conflict arises between humans living on Ganymede and the inhabitants of Jupiter.
In Philip K. Dick’s short-story The Mold of Yancy (1955), Callisto is home to a colony where the people conform to the dictates of Yancy, a public commentator who speaks to them via public broadcasts. In Bruce Sterling’s Schismatrix (1985), Europa is inhabited by a faction of genetically-engineered posthumans that are vying for control of the Solar System.
Alastair Reynolds’s short story “A Spy in Europa” depicts colonies built on the underside of Europa’s icy surface. Meanwhile, a race of genetically-altered humans (called the “Denizens”) are created to live in the subsurface ocean, close to the core-mantle boundary where hydrothermal vents keep the water warm and the native life forms live.
Kim Stanley Robinson’s novels Galileo’s Dream (2009) and 2312 (2012) feature colonies on Io, where settlements are adapted to deal with the volcanically active, hostile surface. The former novel is partly set on Callisto, where a massive city called Valhalla is built around the concentric rings of the moon’s giant crater (also mentioned in 2312).
In Robinson’s The Memory of Whiteness (1985), the protagonists visit Europa, which hosts large human colonies who live around pools of melted ice. And in his novel Blue Mars (1996), Robinson makes a passing description of a flourishing colony on Callisto.
A “family portrait” of the four Galilean satellites (Io Europa, Ganymede and Callisto) around Jupiter, taken by the New Horizons spacecraft and released in 2007. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Proposed Methods:
Since the Voyager probes passed through the Jovian system, several proposals have been made for crewed missions to Jupiter’s moons and even the creation of settlements. For instance, in 1994, the private spaceflight venture known as the Artemis Project was established with the intent of colonizing the Moon in the 21st century.
However, in 1997, they also drafted plans to colonize Europa, which called for igloos to be established on the surface. These would serve as based for scientists who then drill down into the Europan ice crust and explore the sub-surface ocean. This plan also discussed the possible use of “air pockets” in the ice sheet for long-term human habitation.
In 2003, NASA produced a study called Revolutionary Concepts for Human Outer Planet Exploration (HOPE) which addressed future exploration of the Solar System. Because of its distance from Jupiter, and therefore low exposure to radiation, the target destination in this study was the moon Callisto.
The plan called for operations to begin in 2045. These would begin with the creation of a base on Callisto, where science teams would be able to teleoperate a robotic submarine that would be used to explore Europa’s internal ocean. These science teams would also excavate surface samples near their landing site on Callisto.
Last, but not least, the expedition to Callisto would establish a reusable surface habitat where water ice could be harvested and converted into rocket fuel. This base could therefore serve as a resupply base for all future exploitation missions in the Jovian system.
Also in 2003, NASA reported that a manned mission to Callisto might be possible in the 2040s. According to a joint-study released by the Glenn Research Center and the Ohio Aerospace Institute, this mission would rely on a ship equipped with Nuclear-Electric Propulsion (NEP) and artificial gravity, which would transport a crew on a 5-year mission to Callisto to establish a base.
In his book Entering Space: Creating a Spacefaring Civilization (1999), Robert Zubrin advocated mining the atmospheres of the outer planets – including Jupiter – to obtain Helium-3 fuel. A base on one or more of the Galilean moons would be necessary for this. NASA has also speculated on this, citing how it could yield limitless supplies of fuel for fusion reactors here on Earth and anywhere else in the Solar System where colonies exist.
In October of 2012, Elon Musk unveiled his concept for an Mars Colonial Transporter (MCT), which was central to his long-term goal of colonizing Mars. At the time, Musk stated that the first unmanned flight of the Mars transport spacecraft would take place in 2022, followed by the first manned MCT mission departing in 2024.
In September 2016, during the 2016 International Astronautical Congress, Musk revealed further details of his plan, which included the design for an Interplanetary Transport System (ITS) and estimated costs. This system, which was originally intended to transport settlers to Mars, had evolved in its role to transport human beings to more distant locations in the Solar System – including Europa and other Jovian moons.
Potential Benefits:
Establishing colonies on the Galilean moons has many potential benefits for humanity. For one, the Jovian system is incredibly rich in terms of volatiles – which include water, carbon dioxide, and ammonia ices – as well as organic molecules. In addition, it is believed that Jupiter’s moons also contain massive amounts of liquid water.
For example, volume estimates placed on Europa’s interior ocean suggest that it may contain as much as 3 × 1018 m3 – three quadrillion cubic kilometers, or 719.7 trillion cubic miles – of water. This is slightly more than twice the combined volume of all of Earth’s oceans. In addition, colonies on the moons of Jupiter could enable missions to Jupiter itself, where hydrogen and helium-3 could be harvested as nuclear fuel.
Illustration of Europa (foreground), Jupiter (right), and Io (middle) showing water plumes that reach the surface. Credit: NASA/JPL-Caltech
Colonies established on Europa and Ganymede would also allow for multiple exploration missions to be mounted to the interior oceans that these moons are believed to have. Given that these oceans are also thought to be some of the most likely locations for extra-terrestrial life in our Solar System, the ability to examine them up close would be a boon for scientific research.
Colonies on the moons of Io, Europa, Ganymede, and Callisto would also facilitate missions farther out into the Solar System. These colonies could serve as stopover points and resupply bases for missions heading to and from the Cronian system (Saturn’s system of moons) where additional resources could be harvested.
In short, colonies in the Jovian system would provide humanity with access to abundant resources and immense research opportunities. The chance to grow as a species, and become a post-scarcity one at that, are there; assuming that all the challenges can be overcome.
Challenges:
And of course, these challenges are great in size and many in number. They include, but are not limited to, radiation, the long-term effects of lower gravity, transportation issues, lack of infrastructure, and of course, the sheer cost involved. Considering the hazard radiation poses to exploration, it is appropriate to deal with this aspect first.
The magnetic field of Jupiter and co-rotation enforcing currents. Credit: Wikipedia Commons
Io and Europa, being the closest Galileans to Jupiter, receive the most radiation of any of these moons. This is made worse by the fact that neither have a protective magnetic field and very tenuous atmospheres. As such, Io’s surface receives an average of about 3,600 rems per day, while Europa receives about 540 per day.
For comparison, people here on Earth are exposed to less than 1 rem a day (0.62 for those living in developed nations). Exposure to 500 rems a day is likely to be fatal, and exposure to roughly 75 in a period of a few days is enough to cause severe health problems and radiation poisoning.
Ganymede is the only Galilean moon (and only non-gas giant body other than Earth) to have a magnetosphere. However, it is still overpowered by Jupiter’s powerful magnetic field. On average, the moon receives about 8 rads of radiation per day, which is the equivalent of what the surface of Mars is exposed to in an average year.
Only Callisto is far enough from Jupiter that it is not dominated by its magnetic environment. Here, radiation levels only reach about 0.01 rems per day, just a fraction of what we are exposed to here on Earth. However, its distance from Jupiter means that it experiences its fair share of problems as well (not the least of which is a lack of tidal heating in its interior).
Artist’s impression of a base on Callisto. Credit: NASA
Another major issue is the long-term effects the lower gravity on these moons would have on human health. On the Galilean moons, the surface gravity ranges from 0.126 g (for Callisto ) to 0.183 g (for Io). This is comparable to the Moon (0.1654 g), but substantially less than Mars (0.376 g). And while the effects of low-g are not well-understood, it is known that the long-term effect of microgravity include loss of bone density and muscle degeneration.
Compared to other potential locations for colonization, the Jovian system is also very far from Earth. As such, transporting crews and all the heavy equipment necessary to build a colony would be very time-consuming, as would missions where resources were being transported to and from the Jovian moons.
To give you a sense of how long it would take, let’s consider some actual missions to Jupiter. The first spacecraft to travel from Earth to Jupiter was NASA’s Pioneer 10 probe, which launched on March 3rd, 1972, and reached the Jupiter system on December 3, 1973 – 640 days (1.75 or years) of flight time.
Pioneer 11 made the trip in 606 days, but like its predecessor, it was simply passing through the system on its way to the Outer planets. Similarly, the Voyager 1 and 2 probes, which were also passing through the system, took 546 days and 688 days, respectively. For direct missions, like the Galileo probe and the recent Juno mission, the travel time was even longer.
Artist’s concept of a Bimodal Nuclear Thermal Rocket in Low Earth Orbit. Credit: NASA
In the case of Galileo, the probe left Earth on October 18th, 1989, and arrived at Jupiter on December 7th, 1995. In other words, it took 6 years, 1 month, and 19 days to make it to Jupiter from Earth without flying by. Juno, on the other hand, launched from Earth on Aug. 5th, 2011, and achieved orbit around Jupiter on July 5th, 2016 – 1796 days, or just under 5 years.
And, it should be noted, these were uncrewed missions, which involved only a robotic probe and not a vessel large enough to accommodate large crews, supplies and heavy equipment. As a result, colony ships would have to be much larger and heavier, and would require advanced propulsion systems – like nuclear-thermal/nuclear-electric engines – to ensure they made the trip in a reasonable amount of time.
Missions to and from the Jovian moons would also require bases between Earth and Jupiter in order to provide refueling and resupplying, and cut down on the costs of individual missions. This would mean that permanent outposts would need to be established on the Moon, Mars, and most likely in the Asteroid Belt before any missions to Jupiter’s moons were considered feasible or cost-effective.
These last two challenges raise the issue of cost. Between building ships that have the ability to make the trip to Jupiter in a fair amount of time, established the bases needed to support them, and the cost of establishing the colonies themselves, the colonization of the Jovian moons would be incredibly expensive! Combined with the hazards of doing so, one has to wonder if its even worth it.
SpaceX’s newly revealed Interplanetary Transit System will make travel to Mars, and other destinations in our Solar System, possible. Credit: SpaceX
On the other hand, in the context of space exploration and colonization, the idea of establishing permanent human outposts on Jupiter’s moons makes sense. All of the challenges can be addressed, provided the proper precautions are taken and the right kind of resources are committed. And while it will have to wait until after similar colonies/bases are established on the Moon and Mars, it is not a bad idea as far as “next steps” go.
With colonies on any of the Galilean moons, humanity will have a foothold in the outer Solar System, a stopover point for future missions to Saturn and beyond, and access to abundant resources. Again, it all comes down to how much we are willing to spend.
Research into the temporary slowdown of the global mean surface temperature has revealed that the world's oceans have absorbed the "missing heat." Image: Flickr user Brian Richardson, CC by 2.0
A reprieve from Global Warming? A hiatus? That would be nice, wouldn’t it? But in this case, a hiatus is not quite what it seems.
Everybody knows that global warming is partly caused by human activities, largely our use of fossil fuels. We understand how it works and we fear for the future. But there’s been a slowdown in the global mean surface temperature increase between 1998 to 2013. We haven’t lowered our emissions of greenhouse gases (GHGs) significantly during that time, so what happened?
Fossil fuels: we just can’t get enough of them. Image: a petrochemical refinery in Scotland. Credit: User:John from wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2459867
A new multi-institutional study involving NASA’s Jet Propulsion Laboratory (JPL), the National Oceanographic and Atmospheric Institute, and others, concludes that Earth’s oceans have absorbed the heat. So instead of the global mean surface temperature rising at a steady rate, the oceans have taken on the job as global heat sink. But what’s the significance of this?
“The hiatus period gives scientists an opportunity to understand uncertainties in how climate systems are measured, as well as to fill in the gap in what scientists know.” -Xiao-Hai Yan, University of Delaware, Newark
In terms of the on-going rise in the temperature of the globe, the hiatus is not that significant. But in terms of the science of global warming, and how well we understand it, the hiatus gives scientists an opportunity.
The new paper, titled “The Global Warming Hiatus: Slowdown or Redistribution?” grew out of the U.S. Climate Variability and Predictability Program (CLIVAR) panel session at the 2015 American Geophysical Union fall meeting. From those discussions, scientists reached consensus on three key points:
From 1998 to 2013, the rate of global mean surface warming slowed, which some call the “global warming hiatus.”
Natural variability plays a large role in the rate of global mean surface warming on decadal time scales.
Improved understanding of how the ocean distributes and redistributes heat will help the scientific community better monitor Earth’s energy budget. Earth’s energy budget is a complex calculation of how much energy enters our climate system from the sun and what happens to it: how much is stored by the land, ocean or atmosphere.
This graph shows the yearly global ocean heat content. The dashed line shows the 1958-65 average. Image: Balmaseda et al., 2013
The paper is a reminder that climate science is complex, and that the oceans play a big part in global warming. As Yan says, “To better monitor Earth’s energy budget and its consequences, the ocean is most important to consider because the amount of heat it can store is extremely large when compared to the land or atmospheric capacity.”
“…”arguably, ocean heat content — from the surface to the seafloor — might be a more appropriate measure of how much our planet is warming.” – from the paper “The Global Warming Hiatus: Slowdown or Redistribution?”
The team behind this new research suggests that saying there’s been a hiatus in global warming is confusing. They suggest “global warming hiatus” be replaced with “global surface warming slowdown.”
There’s a danger in calling it a “global warming hiatus.” Those opposed to climate change and who think it’s a hoax can use that term to discredit climate science. They’ll claim that the “hiatus” shows we don’t understand climate change and the Earth may have stopped warming. But in any case, it’s the long-term trend—change over the course of a century or more—that defines “global warming,” not the change from year to year or even decade to decade.
There’s much more to learn about the oceans’ role in global warming. Research shows that some ocean areas absorb heat much faster than others. But whatever the fine detail of it is, there is broad agreement in the scientific community that the global surface warming slowdown was caused by an increased uptake of heat energy by the world’s oceans.
A screenshot from the “NASA’s Eyes” app. The app allows anyone to check Earth’s vital signs. Image: NASA/JPL
NASA uses a lot of tools to monitor the Earth’s temperature. For an interesting look at the Earth’s vital signs, check out Nasa’s Eyes. This easy to use visualization tool lets you take a closer look at the Earth’s temperature, CO2 levels, soil moisture levels, sea levels, and other things.
Perhaps the most important question we can possible ask is, “are we alone in the Universe?”.
And so far, the answer has been, “I don’t know”. I mean, it’s a huge Universe, with hundreds of billions of stars in the Milky Way, and now we learn there are trillions of galaxies in the Universe.
Is there life closer to home? What about in the Solar System? There are a few existing places we could look for life close to home. Really any place in the Solar System where there’s liquid water. Wherever we find water on Earth, we find life, so it make sense to search for places with liquid water in the Solar System.
I know, I know, life could take all kinds of wonderful forms. Enlightened beings of pure energy, living among us right now. Or maybe space whales on Titan that swim through lakes of ammonia. Beep boop silicon robot lifeforms that calculate the wasted potential of our lives.
Sure, we could search for those things, and we will. Later. We haven’t even got this basic problem done yet. Earth water life? Check! Other water life? No idea.
It turns out, water’s everywhere in the Solar System. In comets and asteroids, on the icy moons of Jupiter and Saturn, especially Europa or Enceladus. Or you could look for life on Mars.
Sloping buttes and layered outcrops within the “Murray formation” layer of lower Mount Sharp. Credit: NASA
Mars is similar to Earth in many ways, however, it’s smaller, has less gravity, a thinner atmosphere. And unfortunately, it’s bone dry. There are vast polar caps of water ice, but they’re frozen solid. There appears to be briny liquid water underneath the surface, and it occasionally spurts out onto the surface. Because it’s close and relatively easy to explore, it’s been the place scientists have gone looking for past or current life.
Researchers tried to answer the question with NASA’s twin Viking Landers, which touched down in 1976. The landers were both equipped with three biology experiments. The researchers weren’t kidding around, they were going to nail this question: is there life on Mars?
In the first experiment, they took soil samples from Mars, mixed in a liquid solution with organic and inorganic compounds, and then measured what chemicals were released. In a second experiment, they put Earth organic compounds into Martian soil, and saw carbon dioxide released. In the third experiment, they heated Martian soil and saw organic material come out of the soil.
The landing site of Viking 1 on Mars in 1977, with trenches dug in the soil for the biology experiments. Credit: NASA/JPL
Three experiments, and stuff happened in all three. Stuff! Pretty exciting, right? Unfortunately, there were equally plausible non-biological explanations for each of the results. The astrobiology community wasn’t convinced, and they still fight in brutal cage matches to this day. It was ambitious, but inconclusive. The worst kind of conclusive.
Researchers found more inconclusive evidence in 1994. Ugh, there’s that word again. They were studying a meteorite that fell in Antarctica, but came from Mars, based on gas samples taken from inside the rock.
They thought they found evidence of fossilized bacterial life inside the meteorite. But again, there were too many explanations for how the life could have gotten in there from here on Earth. Life found a way… to burrow into a rock from Mars.
NASA learned a powerful lesson from this experience. If they were going to prove life on Mars, they had to go about it carefully and conclusively, building up evidence that had no controversy.
Artist Concept, Mars Exploration Rovers. NASA/JPL-Caltech
The Spirit and Opportunity Rovers were an example of building up this case cautiously. They were sent to Mars in 2004 to find evidence of water. Not water today, but water in the ancient past. Old water Over the course of several years of exploration, both rovers turned up multiple lines of evidence there was water on the surface of Mars in the ancient past.
They found concretions, tiny pebbles containing iron-rich hematite that forms on Earth in water. They found the mineral gypsum; again, something that’s deposited by water on Earth.
A bright mineral vein informally named Homestake. The vein is about the width of a thumb and about 18 inches (45 centimeters) long. Opportunity examined it in November 2011 (Sol 2763) and found it to be rich in calcium and sulfur, possibly the calcium-sulfate mineral gypsum. Credit: NASA/JPL-Caltech
NASA’s Curiosity Rover took this analysis to the next level, arriving in 2012 and searching for evidence that water was on Mars for vast periods of time; long enough for Martian life to evolve.
Once again, Curiosity found multiple lines of evidence that water acted on the surface of Mars. It found an ancient streambed near its landing site, and drilled into rock that showed the region was habitable for long periods of time.
In 2014, NASA turned the focus of its rovers from looking for evidence of water to searching for past evidence of life.
Curiosity found one of the most interesting targets: a strange strange rock formations while it was passing through an ancient riverbed on Mars. While it was examining the Gillespie Lake outcrop in Yellowknife Bay, it photographed sedimentary rock that looks very similar to deposits we see here on Earth. They’re caused by the fossilized mats of bacteria colonies that lived billions of years ago.
A bright and interestingly shaped tiny pebble shows up among the soil on a rock, called “Gillespie Lake,” which was imaged by Curiosity’s Mars Hand Lens Imager on Dec. 19, 2012, the 132nd sol, or Martian day of Curiosity’s mission on Mars. Credit: NASA / JPL-Caltech / MSSS.
Not life today, but life when Mars was warmer and wetter. Still, fossilized life on Mars is better than no life at all. But there might still be life on Mars, right now, today. The best evidence is not on its surface, but in its atmosphere. Several spacecraft have detected trace amounts of methane in the Martian atmosphere.
Methane is a chemical that breaks down quickly in sunlight. If you farted on Mars, the methane from your farts would dissipate in a few hundred years. If spacecraft have detected this methane in the atmosphere, that means there’s some source replenishing those sneaky squeakers. It could be volcanic activity, but it might also be life. There could be microbes hanging on, in the last few places with liquid water, producing methane as a byproduct.
The European ExoMars orbiter just arrived at Mars, and its main job is sniff the Martian atmosphere and get to the bottom of this question.
Are there trace elements mixed in with the methane that means its volcanic in origin? Or did life create it? And if there’s life, where is it located? ExoMars should help us target a location for future study.
The European/Russian ExoMars Trace Gas Orbiter (TGO) will sniff the Martian atmosphere for signs of methane which could originate for either biological or geological mechanisms. Credit: ESA
NASA is following up Curiosity with a twin rover designed to search for life. The Mars 2020 Rover will be a mobile astrobiology laboratory, capable of scooping up material from the surface of Mars and digesting it, scientifically speaking. It’ll search for the chemicals and structures produced by past life on Mars. It’ll also collect samples for a future sample return mission.
Even if we do discover if there’s life on Mars, it’s entirely possible that we and Martian life are actually related by a common ancestor, that split off billions of years ago. In fact, some astrobiologists think that Mars is a better place for life to have gotten started.
Not the dry husk of a Red Planet that we know today, but a much wetter, warmer version that we now know existed billions of years ago. When the surface of Mars was warm enough for liquid water to form oceans, lakes and rivers. And we now know it was like this for millions of years.
A conception of an ancient Mars, flush with oceans, clouds and life. Credit: Kevin Gill.
While Earth was still reeling from an early impact by the massive planet that crashed into it, forming the Moon, life on Mars could have gotten started early.
But how could we actually be related? The idea of Panspermia says that life could travel naturally from world to world in the Solar System, purely through the asteroid strikes that were regularly pounding everything in the early days.
Imagine an asteroid smashing into a world like Mars. In the lower gravity of Mars, debris from the impact could be launched into an escape trajectory, free to travel through the Solar System.
We know that bacteria can survive almost indefinitely, freeze dried, and protected from radiation within chunks of space rock. So it’s possible they could make the journey from Mars to Earth, crossing the orbit of our planet.
Even more amazingly, the meteorites that enter the Earth’s atmosphere would protect some of the bacterial inhabitants inside. As the Earth’s atmosphere is thick enough to slow down the descent of the space rocks, the tiny bacterialnauts could survive the entire journey from Mars, through space, to Earth.
Credit: NASA/JPL-Caltech
If we do find life on Mars, how will we know it’s actually related to us? If Martian life has the similar DNA structure to Earth life, it’s probably related. In fact, we could probably trace the life back to determine the common ancestor, and even figure out when the tiny lifeforms make the journey.
If we do find life on Mars, which is related to us, that just means that life got around the Solar System. It doesn’t help us answer the bigger question about whether there’s life in the larger Universe. In fact, until we actually get a probe out to nearby stars, or receive signals from them, we might never know.
An even more amazing possibility is that it’s not related. That life on Mars arose completely independently. One clue that scientists will be looking for is the way the Martian life’s instructions are encoded. Here on Earth, all life follows “left-handed chirality” for the amino acid building blocks that make up DNA and RNA. But if right-handed amino acids are being used by Martian life, that would mean a completely independent origin of life.
Of course, if the life doesn’t use amino acids or DNA at all, then all bets are off. It’ll be truly alien, using a chemistry that we don’t understand at all.
There are many who believe that Mars isn’t the best place in the Solar System to search for life, that there are other places, like Europa or Enceladus, where there’s a vast amount of liquid water to be explored.
But Mars is close, it’s got a surface you can land on. We know there’s liquid water beneath the surface, and there was water there for a long time in the past. We’ve got the rovers, orbiters and landers on the planet and in the works to get to the bottom of this question. It’s an exciting time to be part of this search.
A lovely view of Saturn and its rings as seen by the Cassini spacecraft on Aug. 12, 2009. Credit: NASA/JPL-Caltech/Space Science Institute.
There is a Twitter-bot that randomly tweets out “NOOOOOOOO Cassini can’t be ending!” (with varying amounts of “O’s”). @CassiniNooo represents the collective sigh of sadness and consternation felt by those of us who can’t believe the the historic and extensive Cassini mission will be over in just a matter of months.
And next week is the beginning of the end for Cassini.
On November 30, Cassini will begin a phase of the mission that the science team calls “Cassini’s Ring-Grazing Orbits,” as the spacecraft will start skimming past the outer edge of the rings, coming within – at times — 4,850 miles (7,800 kilometers) of the rings.
“The scientific return will be incredible,” Linda Spilker, Cassini project scientist, told me earlier this year. “We’ll be studying things we just couldn’t do any other place.”
Between November 30, 2016 and April 22, 2017 Cassini will circle high over and under the poles of Saturn, diving every seven days for a total of 20 times through the unexplored region at the outer edge of the main rings.
During the close passes, Cassini’s instruments will attempt to directly sample the icy ring particles and molecules of faint gases that are found close to the rings. Cassini will also capture some of the best high-resolution images of the rings, and garner the best views ever of the small moons Atlas, Pan, Daphnis and Pandora, which orbit near the rings’ outer edges.
During the first two ring-grazing orbits, the spacecraft will pass directly through an extremely faint ring produced by tiny meteors striking the two small moons Janus and Epimetheus. Later ring crossings in March and April will send the spacecraft through the dusty outer reaches of the F ring.
“Even though we’re flying closer to the F ring than we ever have, … there’s very little concern over dust hazard at that range,” said Earl Maize, Cassini project manager at JPL.
Of course, the ultimate ‘endgame’ is that Cassini will plunge into Saturn with its “Grand Finale,” ending the mission on September 15, 2017. Since Cassini is running out of fuel, destroying the spacecraft is necessary to ensure “planetary protection,” making sure any potential microbes from Earth that may still be attached to the spacecraft don’t contaminate any of Saturn’s potentially habitable moons.
This graphic illustrates the Cassini spacecraft’s trajectory, or flight path, during the final two phases of its mission. The view is toward Saturn as seen from Earth. The 20 ring-grazing orbits are shown in gray; the 22 grand finale orbits are shown in blue. The final partial orbit is colored orange. Image credit: NASA/JPL-Caltech/Space Science Institute
To prepare for the Grand Finale, Cassini engineers have been slowly adjusting the spacecraft’s orbit since January of this year, doing maneuvers and burns of the engine to bring Cassini into the right orbit so that it can ultimately dive repeatedly through the narrow gap between Saturn and its rings, before making its mission-ending plunge. During some of those final orbits, Cassini will pass as close as 1,012 miles (1,628 kilometers) above the cloudtops of Saturn.
One question for Cassini’s engineering team is how much fuel is actually left in the tank for Cassini’s main engines, which do the majority of the work for orbit adjustments. Each time they’ve used the main engines this past year, the team has held their breath, hoping there is enough fuel.
One final burn of the main engine remains, on December 4. This maneuver is important for fine-tuning the orbit and setting the correct course to enable the remainder of the mission, said Maize.
“This will be the 183rd and last currently planned firing of our main engine,” he said. “Although we could still decide to use the engine again, the plan is to complete the remaining maneuvers using thrusters,” said Maize.
A montage of images from Cassini of various moons and the rings around Saturn. Credit: NASA/JPL-Caltech/Space Science Institute
When I visited with Maize and Spilker earlier this year, Spilker wistfully said that they had begun to experience some of the “lasts” of the mission — the final flyby of Enceladus and other moons. And there’s one big “last” coming up: on Nov. 29, 2016, Cassini will come within 6,800 miles (11,000 km) of Titan, the final flyby of this eerily Earthlike but yet totally alien moon.
This final flyby, named Flyby T-125 has two primary goals: Mapmaking of Titan’s surface, and enabling the change in Cassini’s orbit to begin the end of the mission. But it also might be the most daring and thrilling part of Cassini’s nearly 20-year mission.
