Posted on by Matt Williams

Researchers Just Scanned 14 Worlds From the Kepler Mission for “Technosignatures”, Evidence of Advanced Civilizations

A team of astronomers from UCLA searched for "technosignatures" in the Kepler field data. Credit and Copyright: Danielle Futselaar

When it comes to looking for life on extra-solar planets, scientists rely on what is known as the “low-hanging fruit” approach. In lieu of being able to observe these planets directly or up close, they are forced to look for “biosignatures” – substances that indicate that life could exist there. Given that Earth is the only planet (that we know of) that can support life, these include carbon, oxygen, nitrogen and water.

However, while the presence of these elements are a good way of gauging “habitability”, they are not necessarily indications that extra-terrestrial civilizations exist. Hence why scientists engaged in the Search for Extra-Terrestrial Intelligence (SETI) also keep their eyes peeled for “technosignatures”. Targeting the Kepler field, a team of scientists recently conducted a study that examined 14 planetary systems for indications of intelligent life.

The study, titled “A search for technosignatures from 14 planetary systems in the Kepler field with the Green Bank Telescope at 1.15-1.73 GHz“, recently appeared online and is being reviewed for publication by The Astronomical Journal. The team was led by Jean-Luc Margot, the Chair of the UCLA Department of Earth, Planetary, and Space Sciences (UCLA EPSS) and a Professor with UCLA’s Department of Physics and Astronomy.

The Green Bank Telescope is the world’s largest, fully-steerable telescope, which is currently being used in a new SETI (Search for Extraterrestrial Intelligence) attempt to look for possible alien radio signals from Tabby’s Star. Credit: NRAO/AUI/NSF

In addition to Margot, the team consisted of 15 graduate and undergraduate students from UCLA and a postdoctoral researcher from the Green Bank Observatory and the Center for Gravitational Waves and Cosmology at West Virginia University. All of the UCLA students participated in the 2016 course, “Search for Extraterrestrial Intelligence: Theory and Applications“.

Together, the team selected 14 systems from the Kepler catalog and examined them for technosignatures. While radio waves are a common occurrence in the cosmos, not all sources can be easily attributed to natural causes. Where and when this is the case, scientists conduct additional studies to try and rule out the possibility that they are a technosignature. As Professor Margot told Universe Today via email:

“In our article, we define a “technosignature” as any measurable property or effect that provides scientific evidence of past or present technology, by analogy with “biosignatures,” which provide evidence of past or present life.”

For the sake of their study, the team conducted an L-band radio survey of these 14 planetary systems. Specifically, they looked for signs of radio waves in the 1.15 to 1.73 gigahertz (GHz) range. At those frequencies, their study is sensitive to Arecibo-class transmitters located within 450 light-years of Earth. So if any of these systems have civilizations capable of building radio observatories comparable to Arecibo, the team hoped to find out!

Spring 2016 UCLA SETI class with Larry Lesyna. Credit: UCLA

“We searched for signals that are narrow (< 10 Hz) in the frequency domain,” said Margot. “Such signals are technosignatures because natural sources do not emit such narrowband signals… We identified approximately 850,000 candidate signals, of which 19 were of particular interest. Ultimately, none of these signals were attributable to an extraterrestrial source.”

What they found was that of the 850,000 candidate signals, about 99% of them were automatically ruled out because they were quickly determined to be the result of human-generated radio-frequency interference (RFI). Of the remaining candidates, another 99% were also flagged as anthropogenic because their frequencies overlapped with other known sources of RFI – such as GPS systems, satellites, etc.

The 19 candidate signals that remained were heavily scrutinized, but none could be attributed to an extraterrestrial source. This is key when attempting to distinguish potential signs of intelligence from radio signals that come from the only intelligence we know of (i.e. us!) Hence why astronomers have historically been intrigued by strong narrowband signals (like the WOW! Signal, detected in 1977) and the Lorimer Burst detected in 2007.

In these cases, the sources appeared to be coming from the Messier 55 globular cluster and the Large Magellanic Cloud, respectively. The latter was especially fascinating since it was the first time that astronomers had observered what are now known as Fast Radio Bursts (FRBs). Such bursts, especially when they are repeating in nature, are considered to be one of the best candidates in the search for intelligent, technologically-advanced life.

The UCLA SETI Group banner, featuring a photo of the central region of the Milky Way Galaxy. Credit: Yuri Beletsky/Carnegie Las Campanas Observatory

Unfortunately, these sources are still being investigated and scientists cannot attribute them to unnatural causes just yet. And as Professor Margot indicated, this study (which covered only 14 of the many thousand exoplanets discovered by Kepler) is just the tip of the iceberg:

“Our study encompassed only a small fraction of the search volume.  For instance, we covered less than five-millionths of the entire sky.  We are eager to scale the effort to sample a larger fraction of the search volume. We are currently seeking funds to expand our search.”

Between Kepler‘s first and second mission (K2), a total of 5,118 candidates and 2,538 confirmed exoplanets have been discovered within our galaxy alone. As of February 1st, 2018, a grand total of 3,728 exoplanets have been confirmed in 2,794 systems, with 622 systems having more than one planet. On top of that, a team of researchers from the University of Oklahoma recently made the first detection of extra-galactic planets as well!

It would therefore be no exaggeration to say that the hunt for ETI is still in its infancy, and our efforts are definitely beginning to pick up speed. There is literally a Universe of possibilities out there and to think that there are no other civilizations that are also looking for us seems downright unfathomable. To quote the late and great Carl Sagan: “The Universe is a pretty big place. If it’s just us, seems like an awful waste of space.”

And be sure to check out this video of the 2017 UCLA SETI Group, courtesy of the UCLA EPSS department:

Further Reading: arXiv

Posted on by Matt Williams

The Solar System Probably has Thousands of Captured Interstellar Asteroids

Artist’s impression of the first interstellar asteroid/comet, "Oumuamua". This unique object was discovered on 19 October 2017 by the Pan-STARRS 1 telescope in Hawaii. Credit: ESO/M. Kornmesser

On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) in Hawaii announced the first-ever detection of an interstellar asteroid, named 1I/2017 U1 (aka. ‘Oumuamua). Originally thought to be a comet, this interstellar visitor quickly became the focus of follow-up studies that sought to determine its origin, structure, composition, and rule out the possibility that it was an alien spacecraft!

While ‘Oumuamua is the first known example of an interstellar asteroid reaching our Solar System, scientists have long suspected that such visitors are a regular occurrence. Aiming to determine just how common, a team of researchers from Harvard University conducted a study to measure the capture rate of interstellar asteroids and comets, and what role they may play in the spread of life throughout the Universe.

The study, titled “Implications of Captured Interstellar Objects for Panspermia and Extraterrestrial Life“, recently appeared online and is being considered for publication in The Astrophysical Journal. The study was conducted by Manasavi Lingam, a postdoc at the Harvard Institute for Theory and Computation (ITC), and Abraham Loeb, the chairman of the ITC and a researcher at the Harvard-Smithsonian Center for Astrophysics (CfA).

For the sake of their study, Lingam and Loeb constructed a three-body gravitational model, where the physics of three bodies are used to compute their respective trajectories and interactions with one another. In Lingam and Loeb’s model, Jupiter and the Sun served as the two massive bodies while a far less massive interstellar object served as the third. As Dr. Loeb explained to Universe Today via email:

“The combined gravity of the Sun and Jupiter acts as a ‘fishing net’. We suggest a new approach to searching for life, which is to examine the interstellar objects captured by this fishing net instead of the traditional approach of looking through telescope or traveling with spacecrafts to distant environments to do the same.”

Using this model, the pair then began calculating the rate at which objects comparable in size to ‘Oumuamua would be captured by the Solar System, and how often such objects would collide with the Earth over the course of its entire history. They also considered the Alpha Centauri system as a separate case for the sake of comparison. In this binary system, Alpha Centauri A and B serve as the two massive bodies and an interstellar asteroid as the third.

As Dr. Lingam indicated:

“The frequency of these objects is determined from the number density of such objects, which has been recently updated based on the discovery of ‘Oumuamua. The size distribution of these objects is unknown (and serves as a free parameter in our model), but for the sake of obtaining quantitative results, we assumed that it was similar to that of comets within our Solar System.”

The theory of Lithopanspermia states that life can be shared between planets within a planetary system. Credit: NASA

In the end, they determined that a few thousands captured objects might be found within the Solar system at any time – the largest of which would be tens of km in radius. For the Alpha Centauri system, the results were even more interesting. Based on the likely rate of capture, and the maximum size of a captured object, they determined that even Earth-sized objects could have been captured in the course of the system’s history.

In other words, Alpha Centauri may have picked up some rogue planets over time, which would have had drastic impact on the evolution  of the system. In this vein, the authors also explored how objects like ‘Oumuamua could have played a role in the distribution of life throughout the Universe via rocky bodies. This is a variation on the theory of lithopanspermia, where microbial life is shared between planets thanks to asteroids, comets and meteors.

In this scenario, interstellar asteroids, which originate in distant star systems, would be the be carriers of microbial life from one system to another. If such asteroids collided with Earth in the past, they could be responsible for seeding our planet and leading to the emergence of life as we know it. As Lingam explained:

“These interstellar objects could either crash directly into a planet and thus seed it with life, or be captured into the planetary system and undergo further collisions within that system to yield interplanetary panspermia (the second scenario is more likely when the captured object is large, for e.g. a fraction of the Earth’s radius).”

In addition, Lingam and Loeb offered suggestions on how future visitors to our Solar System could be studied. As Lingam summarized, the key would be to look for specific kinds of spectra from objects in our Solar Systems:

“It may be possible to look for interstellar objects (captured/unbound) in our Solar system by looking at their trajectories in detail. Alternatively, since many objects within the Solar system have similar ratios of oxygen isotopes, finding objects with very different isotopic ratios could indicate their interstellar origin. The isotope ratios can be determined through high-resolution spectroscopy if and when interstellar comets approach close to the Sun.”

“The simplest way to single out the objects who originated outside the Solar System, is to examine the abundance ratio of oxygen isotopes in the water vapor that makes their cometary tails,” added Loeb. “This can be done through high resolution spectroscopy. After identifying a trapped interstellar object, we could launch a probe that will search on its surface for signatures of primitive life or artifacts of a technological civilization.”

It would be no exaggeration to say that the discovery of ‘Oumuamua has set off something of a revolution in astronomy. In addition to validating something astronomers have long suspected, it has also provided new opportunities for research and the testing of scientific theories (such as lithopanspermia).

In the future, with any luck, robotic missions will be dispatched to these bodies to conduct direct studies and maybe even sample return missions. What these reveal about our Universe, and maybe even the spread of life throughout, is sure to be very illuminating!

Further Reading: arXiv

Posted on by Matt Williams

Here’s a Prediction About the Orbit Musk’s Tesla is Going to Take Through the Solar System

The Falcon Heavy, once operational, will be the most powerful rocket in the world. Credit: SpaceX

After multiple delays, SpaceX recently announced that the inaugural flight of their Falcon Heavy rocket would take place this Tuesday, February 6th, 2018. This rocket, which is the heaviest launch vehicle in the SpaceX fleet (and the most powerful operational rocket in the world right now), is not only central to the company’s vision of reusable rockets, but also to Musk’s long-term vision of sending humans to Mars.

As a result, people all over the world have been tuning in to watch the coverage of the event, and eagerly waiting to see the rocket take off before its launch window closes at 04:00 pm (PST) this afternoon. In keeping with Musk’s habit of sending interesting payloads into space, the rocket will be carrying his cherry-red Tesla Roadster, with the goal of depositing it into a stable orbit around Mars.

According to previous statements made by Musk, the plan calls for the Falcon Heavy to launch the Roadster on a Hohmann Transfer trajectory, an orbital maneuver where a satellite or spacecraft is transferred from one circular orbit to another. After being placed in an elliptical orbit between Earth and Mars, the Roadster would be picked up by Mars’ gravity and remain in orbit around it for (according to Musk) up to a billion years!

To add to the peculiarity of the mission payload, Musk has also been clear that he wants the car to be playing “Space Oddity” – the famous song written and performed by the late and great David Bowie – as its launched into space. This classic song recently got a shot in the arm thanks to Canadian astronaut Chris Hadfield, who performed a rendition of the song while still serving as the commander of Expedition 35 aboard the International Space Station.

But unlike Hadfield’s more positive rendition of the song (which you can watch above), in which the astronaut (Major Tom) does NOT die, Musk’s Roadster will be belting out this tune in its original form. One can only assume that he’s not a particularly superstitious man, or just has a very quirky sense of humor. Considering that a previous payload consisted of a wheel of cheese, I think we know the answer!

Musk confirmed that the launch would take place at 0:130 pm EST (10:30 am PST) in a tweet he posted yesterday, where he stated:

This was followed by an additional tweet posted at 07:59 am PST, which indicated that the launch was still on. However, Musk announced that there would be a minor delay at 09:02 am PST, which was apparently weather-related:

“About 2.5 hours to T-0 for Falcon Heavy. Watch sim for highlight reel of what we hope happens. Car actually takes 6 months to cover 200M+ miles to Mars”

“Upper atmosphere winds currently 20% above max allowable load. Holding for an hour to allow winds to diminish. “

In addition, changes were seen in the countdown clocks run by the US Air Force’s Eastern Range operations. This pushed the launch from its original time of 01:30 pm to 03:19 pm EST (12:19 am PST), and then led to the count being placed on hold.  By 10:52 am PST this morning, the launch clock resumed and Musk indicated that the takeoff would commence at 3:45 pm EST (12:45 PST).

This was followed by the SpaceX ground crew commencing procedures to fuel the rocket at about 11:22 am PST.

Naturally, there has been plenty of speculation about the possible outcome of the mission. Max Fagin, an aerospace engineer from Colorado and a space camp alumni, is one such person. In a video he uploaded to his Youtube channel yesterday (Feb. 5th, 2018), he clarified what the proposed launch entails and offered his thoughts on what will likely happen to the Roadster once its sent into space.

Addressing Musk’s stated goal of a Hohmann Transfer that would put the roadster into Mars’ orbit, he indicated that Musk must have been oversimplifying because there’s no reason to launch a spacecraft on such a trajectory right now. This is due to the fact that this maneuver only makes sense when Earth and Mars are at the closest points in their orbits to each other – aka. when Mars is at opposition.

This is not the case at present, and won’t be again until April-May of this year. At that point, Earth and Mars will be the closest they have been to each other since the year 2000, and will not be in such a perfect opposition again until 2033. As a result, says Fagin, a “true Hohmann Transfer launched from Earth to Mars right now would take the Roadster no closer than 90 million km from Mars – 0.6 times the distance from Earth to the Sun.”

Having said all that, here is what Fagin thinks is actually going to happen:

“Given how light the Roadster is, and given how powerful the Falcon Heavy is, I suspect Falcon heavy is going to impart a little extra delta-v to the Roadster, beyond what would be required for a minimum-energy Hohmann Transfer. This would allow the Roadster to get as close to Mars as SpaceX wanted sometime in October of 2018.”

According to Fagin’s analysis, the Roadster would still not be able to remain in the same orbit of Mars for a billion years, which was Musk’s stated goal. But it would achieve a more stable orbit than a basic Hohmann Transfer would accomplish. In that scenario, the orbit would be perturbed by close encounters with Earth, and the Roadster might eventually come back to Earth.

In other words, the plan may be more complicated than originally stated, but could be largely successful all the same. Come what may, there is no shortage of people who want to see this rocket successfully take off! After all, it’s not only SpaceX’s future that is riding on the outcome of this launch, but perhaps even the future of space exploration itself. Cheaper costs and restored launch capability, that’s what it’s all about!

Barring any further delays, which will push the launch back until tomorrow, the launch will be taking place in T-minus 20 minutes (as of the penning of this article)! In the meantime, be sure to check out SpaceX’s live coverage of the event, which begins today (Tuesday, Feb. 6th) at 12:45 pm (GMT-8):

Further Reading: SpaceX webcast, SpaceX, Twitter (Elon Musk), Orlando Sentinel

Posted on by Matt Williams

ESA’s ExoMars has Completed its Aerobraking Maneuvers to Bring it Into a Circular 400 km Orbit Around Mars

Artist’s impression depicting the separation of the ExoMars 2016 entry, descent and landing demonstrator module, named Schiaparelli, from the Trace Gas Orbiter, and heading for Mars. Credit: ESA/D. Ducros

In March of 2016, the European Space Agency (ESA) launched the ExoMars (Exobiology on Mars) mission into space. A joint project between the ESA and Roscosmos, this two-part mission consisted of the Trace Gas Orbiter (TGO) and the Schiaparelli lander, both of which arrived in orbit around Mars in October of 2016. While Schiaparelli crashed while attempting to land, the TGO has gone on to accomplish some impressive feats.

For example, in March of 2017, the orbiter commenced a series of aerobraking maneuvers, where it started to lower its orbit to enter Mars’ thin atmosphere and slow itself down. According to Armelle Hubault, the Spacecraft Operations Engineer on the TGO flight control team, the ExoMars mission has made tremendous progress and is well on its way to establishing its final orbit around the Red Planet.

TGO’s mission has been to study the surface of Mars, characterize the distribution of water and chemicals beneath the surface, study the planet’s geological evolution, identify future landing sites, and to search for possible biosignatures of past Martian life. Once it has established its final orbit around Mars – 400 km (248.5 mi) from the surface – the TGO will be ideally positioned to conduct these studies.

Visualization of the ExoMars mission’s Trace Gas Orbiter conducting aerobraking maneuvers to March of 2018. Credit: ESA

The ESA also released a graphic (shown above) demonstrating the successive orbits the TGO has made since it began aerobraking – and will continue to make until March of 2018. Whereas the red dot indicates the orbiter (and the blue line its current orbit), the grey lines show successive reductions in the TGO’s orbital period. The bold lines denote a reduction of 1 hour while the thin lines denote a reduction of 30 minutes.

Essentially, a single aerobraking maneuver consist of the orbiter passing into Mars’ upper atmosphere and relying on its solar arrays to generate tiny amounts of drag. Over time, this process slows the craft down and gradually lowers its orbit around Mars. As Armelle Hubault recently posted on the ESA’s rocket science blog:

“We started on the biggest orbit with an apocentre (the furthest distance from Mars during each orbit) of 33 200 km and an orbit of 24 hr in March 2017, but had to pause last summer due to Mars being in conjunction. We recommenced aerobraking in August 2017, and are on track to finish up in the final science orbit in mid-March 2018. As of today, 30 Jan 2018, we have slowed ExoMars TGO by 781.5 m/s. For comparison, this speed is more than twice as fast as the speed of a typical long-haul jet aircraft.”

Earlier this week, the orbiter passed through the point where it made its closest approach to the surface in its orbit (the pericenter passage, represented by the red line). During this approach, the craft dipped well into Mars’ uppermost atmosphere, which dragged the aircraft and slowed it down further. In its current elliptical orbit, it reaches a maximum distance of 2700 km (1677 mi) from Mars (it’s apocenter).

Visualization of the ExoMars Trace Gas Orbiter aerobraking at Mars. Credit: ESA/ATG medialab

Despite being a decades-old practice, aerobraking remains a significant technical challenge for mission teams. Every time a spacecraft passes through a planet’s atmosphere, its flight controllers need to make sure that its orientation is just right in order to slow down and ensure that the craft remains stable. If their calculations are off by even a little, the spacecraft could begin to spin out of control and veer off course. As Hubault explained:

“We have to adjust our pericentre height regularly, because on the one hand, the martian atmosphere varies in density (so sometimes we brake more and sometimes we brake less) and on the other hand, martian gravity is not the same everywhere (so sometimes the planet pulls us down and sometimes we drift out a bit). We try to stay at about 110 km altitude for optimum braking effect. To keep the spacecraft on track, we upload a new set of commands every day – so for us, for flight dynamics and for the ground station teams, it’s a very demanding time!”

The next step for the flight control team is to use the spacecraft’s thrusters to maneuver the spacecraft into its final orbit (represented by the green line on the diagram). At this point, the spacecraft will be in its final science and operation data relay orbit, where it will be in a roughly circular orbit about 400 km (248.5 mi) from the surface of Mars. As Hubault wrote, the process of bringing the TGO into its final orbit remains a challenging one.

“The main challenge at the moment is that, since we never know in advance how much the spacecraft is going to be slowed during each pericentre passage, we also never know exactly when it is going to reestablish contact with our ground stations after pointing back to Earth,” she said. “We are working with a 20-min ‘window’ for acquisition of signal (AOS), when the ground station first catches TGO’s signal during any given station visibility, whereas normally for interplanetary missions we have a firm AOS time programmed in advance.”

Artist’s impression of the ESA’s Exomars 2020 rover, which is expected to land on the surface of Mars by the Spring of 2o21. Credit:ESA

With the spacecraft’s orbital period now shortened to less than 3 hours, the flight control team has to go through this exercise 8 times a day now. Once the TGO has reached its final orbit (by March of 2018), the orbiter will remain there until 2022, serving as a telecommunications relay satellite for future missions. One of its tasks will be to relay data from the ESA’s ExoMars 2020 mission, which will consist of a European rover and a Russian surface platform being deployed the surface of Mars in the Spring of 2021.

Along with NASA’s Mars 2020 rover, this rover/lander pair will be the latest in a long line of robotic missions looking to unlock the secrets of Mars past. In addition, these missions will conduct crucial investigations that will pave the way for eventual sample return missions to Earth, not to mention crewed to the surface!

Further Reading: ESA

Posted on by Matt Williams

Astronomers use a Galaxy Cluster as an Extremely Powerful “Natural Telescope” to Peer Even Farther into the Universe

This illustration shows how gravitational lensing works. The gravity of a large galaxy cluster is so strong, it bends, brightens and distorts the light of distant galaxies behind it. The scale has been greatly exaggerated; in reality, the distant galaxy is much further away and much smaller. Credit: NASA, ESA, L. Calcada

When it comes to studying some of the most distant and oldest galaxies in the Universe, a number of challenges present themselves. In addition to being billions of light years away, these galaxies are often too faint to see clearly. Luckily, astronomers have come to rely on a technique known as Gravitational Lensing, where the gravitational force of a large object (like a galactic cluster) is used to enhance the light of these fainter galaxies.

Using this technique, an international team of astronomers recently discovered a distant and quiet galaxy that would have otherwise gone unnoticed. Led by researchers from the University of Hawaii at Manoa, the team used  the Hubble Space Telescope to conduct the most extreme case of gravitational lensing to date, which allowed them to observe the faint galaxy known as eMACSJ1341-QG-1.

The study that describes their findings recently appeared in The Astrophysical Journal Letters under the title “Thirty-fold: Extreme Gravitational Lensing of a Quiescent Galaxy at z = 1.6″. Led by Harald Ebeling, an astronomer from the University of Hawaii at Manoa, the team included members from the Niels Bohr Institute, the Centre Nationale de Recherche Scientifique (CNRS), the Space Telescope Science Institute, and the European Southern Observatory (ESO).

The quiescent galaxy eMACSJ1341-QG-1 as seen by the Hubble Space Telescope. The yellow dotted line traces the boundaries of the galaxy’s gravitationally lensed image. The inset on the upper left shows what eMACSJ1341-QG-1 would look like if we observed it directly, without the cluster lens. Credit: Harald Ebeling/UH IfA

For the sake of their study, the team relied on the massive galaxy cluster known as eMACSJ1341.9-2441 to magnify the light coming from eMACSJ1341-QG-1,  a distant and fainter galaxy. In astronomical terms, this galaxy is an example of a “quiescent galaxy”, which are basically older galaxies that have largely depleted their supplies of dust and gas and therefore do not form new stars.

The team began by taking images of the faint galaxy with the Hubble and then conducting follow-up spectroscopic observations using the ESO/X-Shooter spectrograph – which is part of the Very Large Telescope (VLT) at the Paranal Observatory in Chile. Based on their estimates, the team determined that they were able to amplify the background galaxy by a factor of 30 for the primary image, and a factor of six for the two remaining images.

This makes eMACSJ1341-QG-1 the most strongly amplified quiescent galaxy discovered to date, and by a rather large margin! As Johan Richard – an assistant astronomer at the University of Lyon who performed the lensing calculations, and a co-author on the study – indicated in a University of Hawaii News release:

“The very high magnification of this image provides us with a rare opportunity to investigate the stellar populations of this distant object and, ultimately, to reconstruct its undistorted shape and properties.”

A spiral galaxy ablaze in the blue light of young stars from ongoing star formation (left) and an elliptical galaxy bathed in the red light of old stars (right). Credit: Sloan Digital Sky Survey, CC BY-NC.

Although other extreme magnifications have been conducted before, this discovery has set a new record for the magnification of a rare quiescent background galaxy. These older galaxies are not only very difficult to detect because of their lower luminosity; the study of them can reveal some very interesting things about the formation and evolution of galaxies in our Universe.

As Ebeling, an astronomer with the UH’s Institute of Astronomy and the lead author on the study, explained:

“We specialize in finding extremely massive clusters that act as natural telescopes and have already discovered many exciting cases of gravitational lensing. This discovery stands out, though, as the huge magnification provided by eMACSJ1341 allows us to study in detail a very rare type of galaxy.”

Quiescent galaxies are common in the local Universe, representing the end-point of galactic evolution. As such, this record-breaking find could provide some unique opportunities for studying these older galaxies and determining why star-formation ended in them. As Mikkel Stockmann, a team member from the University of Copenhagen and an expert in galaxy evolution, explained:

“[A]s we look at more distant galaxies, we are also looking back in time, so we are seeing objects that are younger and should not yet have used up their gas supply. Understanding why this galaxy has already stopped forming stars may give us critical clues about the processes that govern how galaxies evolve.”

An artist’s impression of the accretion disc around the supermassive black hole that powers an active galaxy. Credit: NASA/Dana Berry, SkyWorks Digital

In a similar vein, recent studies have been conducted that suggest that the presence of a Supermassive Black Hole (SMBH) could be what is responsible for galaxies becoming quiescent. As the powerful jets these black holes create begin to drain the core of galaxies of their dust and gas, potential stars find themselves starved of the material they would need to undergo gravitational collapse.

In the meantime, follow-up observations of eMACSJ1341-QG1 are being conducted using telescopes at the Paranal Observatory in Chile and the Maunakea Observatories in Hawaii. What these observations reveal is sure to tell us much about what will become of our own Milky Way Galaxy someday, when the last of the dust and gas is depleted and all its stars become red giants and long-lived red dwarfs.

Further Reading: University of Hawa’ii News, The Astrophysical Journal Letters

Posted on by Matt Williams

For the First Time, Planets Have Been Discovered in ANOTHER Galaxy!

Using the microlensing metthod, a team of astrophysicists have found the first extra-galactic planets! Credit: NASA/Tim Pyle

The first confirmed discovery of a planet beyond our Solar System (aka. an Extrasolar Planet) was a groundbreaking event. And while the initial discoveries were made using only ground-based observatories, and were therefore few and far between, the study of exoplanets has grown considerably with the deployment of space-based telescopes like the Kepler space telescope.

As of February 1st, 2018, 3,728 planets have been confirmed in 2,794 systems, with 622 systems having more than one planet. But now, thanks to a new study by a team of astrophysicists from the University of Oklahoma, the first planets beyond our galaxy have been discovered! Using a technique predicting by Einstein’s Theory of General Relativity, this team found evidence of planets in a galaxy roughly 3.8 billion light years away.

The study which details their discovery, titled “Probing Planets in Extragalactic Galaxies Using Quasar Microlensing“, recently appeared in The Astrophysical Journal Letters. The study was conducted by Xinyu Dai and Eduardo Guerras, a postdoctoral researcher and professor from the Homer L. Dodge Department of Physics and Astronomy at the University of Oklahoma, respectively.

For the sake of their study, the pair used the Gravitational Microlensing technique, which relies on the gravitational force of distant objects to bend and focus light coming from a star. As a planet passes in front of the star relative to the observer (i.e. makes a transit), the light dips measurably, which can then be used to determine the presence of a planet.

In this respect, Gravitational Microlensing is a scaled-down version of Gravitational Lensing, where an intervening object (like a galaxy cluster) is used to focus light coming from a galaxy or other large object located beyond it. It also incorporates a key element of the highly-effective Transit Method, where stars are monitored for dips in brightness to indicate the presence of an exoplanet.

In addition to this method, which is the only one capable of detecting extra-solar planets at truly great distances (on the order of billions of light years), the team also used data from NASA’s Chandra X-ray Observatory to study a distant quasar known as RX J1131–1231. Specifically, the team relied on the microlensing properties of the supermassive black hole (SMBH) located at the center of RX J1131–1231.

They also relied on the OU Supercomputing Center for Education and Research to calculate the microlensing models they employed. From this, they observed line energy shifts that could only be explained by the presence of of about 2000 unbound planets between the quasar’s stars – which ranged from being as massive as the Moon to Jupiter – per main-sequence star.

Image of the gravitational lens RX J1131-1231 galaxy with the lens galaxy at the center and four lensed background quasars. It is estimated that there are trillions of planets in the center elliptical galaxy in this image. Credit: University of Oklahoma

As Xinyu Dai explained in a recent University of Oklahoma press release:

“We are very excited about this discovery. This is the first time anyone has discovered planets outside our galaxy. These small planets are the best candidate for the signature we observed in this study using the microlensing technique. We analyzed the high frequency of the signature by modeling the data to determine the mass.”

While 53 planets have been discovered within the Milky Way galaxy using the Microlensing technique, this is the first time that planets have been observed in other galaxies. Much like the first confirmed discovery of an extra-solar planet, scientists were not even certain planets existed in other galaxies prior to this study. This discovery has therefore brought the study of planets beyond our Solar System to a whole new level!

And as Eduardo Guerras indicated, the discovery was possible thanks to improvements made in both modelling and instrumentation in recent years:

“This is an example of how powerful the techniques of analysis of extragalactic microlensing can be. This galaxy is located 3.8 billion light years away, and there is not the slightest chance of observing these planets directly, not even with the best telescope one can imagine in a science fiction scenario. However, we are able to study them, unveil their presence and even have an idea of their masses. This is very cool science.”

In the future, exoplanet discoveries are likely to be made within and beyond the Milky Way Galaxy. Credit: NASA

In the coming years, more sophisticated observatories will be available, which will allow for even more in the way of discoveries. These include space-based instruments like the James Webb Space Telescope (which is scheduled to launch in Spring of 2019) and ground-based observatories like the ESO’s OverWhelmingly Large (OWL) Telescope, the Very Large Telescope (VLT), the Extremely Large Telescope (ELT), and the Colossus Telescope.

At this juncture, the odds are good that some of these discoveries will be in neighboring galaxies. Perhaps then we can begin to determine just how common planets are in our Universe. At present, it is estimated that could be as many as 100 billion planets in the Milky Way Galaxy alone! But with an estimated 1 to 2 trillion galaxies in the Universe… well, you do the math!

Further Reading: University of Oklahoma, The Astrophysical Journal Letters

Posted on by Matt Williams

12,800 Years Ago, Earth Was Struck by a Disintegrating Comet, Setting Off Global Firestorms

According to a new study, a comet impact triggered massive wildfires and a temporary cooling 12,800 years ago. Credit: NASA/Don Davis

According to modern theories of geological evolution, the last major ice age (known as the Pliocene-Quaternary glaciation) began about 2.58 million years ago during the late Pliocene Epoch. Since then, the world has experienced several glacial and interglacial periods, and has been in an inter-glacial period (where the ice sheets have been retreating) ever since the last glacial period ended about 10,000 years ago.

According to new research, this trend experienced a bit of a hiccup during the late Paleolithic era. It was at this time – roughly 12,800 years ago, according to a new study from the University of Kansas – that a comet struck our planet and triggered massive wildfires. This impact also triggered a short glacial period that temporarily reversed the previous period of warming, which had a drastic affect on wildlife and human development.

The study in question, “Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ~12,800 Years Ago”, was so large that it was divided into two parts. Part I. Ice Cores and Glaciers; and Part II. Lake, Marine, and Terrestrial Sediments, were both recently published by The Journal of Geography, part of the the University of Chicago Press’ series of scientific publications.

New research shows that some 12,800 years ago, an astonishing 10 percent of the Earth’s land surface, or about 10 million square kilometers, was consumed by fires. Credit: Pexels.com

Led by Wendy S. Wolbach, a Professor of inorganic chemistry, geochemistry and analytical chemistry at Chicago’s De Paul University, the study was conducted by a team of 24 scientists and included members from the Tennessee Valley Authority (TVA), the Climate Change Institute, the Instituto de Investigaciones en Ciencias de la Tierra (INICIT), the Lawrence Berkeley National Laboratory, and multiple universities.

For the sake of their study, the team combined data from ice core, forest, pollen and other geochemical and isotopic markers obtained from more than 170 different sites across the world. Based on this data, the team concluded that roughly 12,800 years ago, a global disaster was triggered when a stream of fragments from a comet measuring about 100 km (62 mi) in diameter exploded in Earth’s atmosphere and rained down on the surface.

As KU Emeritus Professor of Physics & Astronomy Adrian Melott explained in a KU press release:

“The hypothesis is that a large comet fragmented and the chunks impacted the Earth, causing this disaster. A number of different chemical signatures — carbon dioxide, nitrate, ammonia and others — all seem to indicate that an astonishing 10 percent of the Earth’s land surface, or about 10 million square kilometers, was consumed by fires.”

Ice ages are characterized by a drop in average global temperatures, resulting in the expansion of ice sheets globally. Credit: NASA

According to their research, these massive wildfires also caused a massive feedback in Earth’s climate. As fires rushed across much of the planet’s landscape, the smoke and dust clogged the sky and blocked out sunlight. This triggered rapid cooling in the atmosphere, causing plants to die, food sources to dwindle, and ocean levels to drop. Last, but not least, the ice sheets which had been previously retreating began to advance again.

This quasi-ice age, according to the study, lasted about another thousand years. When the climate began to warm again, life began to recover, but was faced with a number of drastic changes. For example, fewer large animals survived, which affected the hunter-gather culture of humans all across North America. This was reflected in the different types of spear points that have been dated to this period.

What’s more, pollen samples obtained from this period indicate that pine forests were likely burned off and were replaced by poplar forests, a species that colonizes cleared areas. The authors also suggest that this impact could have been responsible for the so-called Younger Dryas cool episode. This period occurred roughly 12,000 years ago, where gradual climatic warming was temporarily reversed.

Intrinsic to this period was an increase of biomass burning and the extinctions of larger species during the late Pleistocene period (ca. 2,588,000 to 11,700 years ago). These sudden changes are believed to be what led to severe shifts in human populations, causing a decline during the 1000-year cold period, and leading to the adoption of agriculture and animal husbandry once the climate began to warm again.

Pleistocene of Northern Spain showing woolly mammoth, cave lions eating a reindeer, tarpans, and woolly rhinoceros. Credit: Wikipedia Commons/Mauricio Antón

In short, this new theory could help explain a number of changes that made humanity what it is today. As Mellot indicated:

“Computations suggest that the impact would have depleted the ozone layer, causing increases in skin cancer and other negative health effects. The impact hypothesis is still a hypothesis, but this study provides a massive amount of evidence, which we argue can only be all explained by a major cosmic impact.”

These studies not only provide insight into the timeline of Earth’s geological evolution, they also sheds light on the history of the Solar System. According to this study, the remnants of the meteor which struck Earth still persist within our Solar System today. Last, but not least, the climate shifts that these impacts created had a profound effect on the evolution of life here on Earth.

Further Reading: Kansas University

Posted on by Matt Williams

Outflows From Black Holes are Creating New Molecules Where There Should Only be Destruction

Artist's impression of the black hole wind at the center of a galaxy. Credit: ESA

During the 1960s, scientists discovered a massive radio source (known as Sagittarius A*) at the center of the Milky Way, which was later revealed to be a Supermassive Black Holes (SMBH). Since then, they have learned that these SMBHs reside at the center of most massive galaxies. The presence of these black holes is also what allows the centers of these galaxies to have a higher than normal luminosity – aka. Active Galactic Nuclei (AGNs).

In the past few years, astronomers have also observed fast molecular outflows emanating from AGNs which left them puzzled. For one, it was a mystery how any particles could survive the heat and energy of a black hole’s outflow. But according to a new study produced by researchers from Northwestern University, these molecules were actually born within the winds themselves. This theory may help explain how stars form in extreme environments.

The study recently appeared in The Monthly Notices of the Royal Astronomical Society under the title “The origin of fast molecular outflows in quasars: molecule formation in AGN-driven galactic winds.” The study was conducted by Lindheimer post-doctoral fellow Alexander J Richings and assistant professor Claude-André Faucher-Giguère from Northwestern University’s Center for Interdisciplinary Research and Exploration in Astrophysics (CIERA).

Artist’s impression of a black hole’s wind sweeping away galactic gas. Credit: ESA

For the sake of their study, Richings developed the first-ever computer code capable of modeling the detailed chemical processes in interstellar gas which are accelerated by a growing SMBH’s radiation. Meanwhile, Claude-André Faucher-Giguère contributed his expertise, having spent his career studying the formation and evolution of galaxies. As Richings explained in a Northwestern press release:

“When a black hole wind sweeps up gas from its host galaxy, the gas is heated to high temperatures, which destroy any existing molecules. By modeling the molecular chemistry in computer simulations of black hole winds, we found that this swept-up gas can subsequently cool and form new molecules.”

The existence of energetic outflows form SMBHs was first confirmed in 2015, when researchers used the ESA’s Herschel Space Observatory and data from the Japanese/US Suzaku satellite to observe the AGN of a galaxy known as IRAS F11119+3257. Such outflows, they determined, are responsible for draining galaxies of their interstellar gas, which has an arresting effect on the formation of new stars and can lead to “red and dead” elliptical galaxies.

This was followed-up in 2017 with observations that indicated that rapidly moving new stars formed in these outflows, something that astronomers previously thought to be impossible because of the extreme conditions present within them. By theorizing that these particles are actually the product of black hole winds, Richings and Faucher-Giguère have managed to address questions raised by these previous observations.

Artist's concept of Sagittarius A, the supermassive black hole at the center of our galaxy. Credit: NASA/JPL
Artist’s concept of Sagittarius A, the supermassive black hole at the center of our galaxy. Credit: NASA/JPL

Essentially, their theory helps explain predictions made in the past, which appeared contradictory at first glance. On the one hand, it upholds the prediction that black hole winds destroy molecules they collide with. However, it also predicts that new molecules are formed within these winds – including hydrogen, carbon monoxide and water – which can give birth to new stars. As Faucher-Giguère explained:

“This is the first time that the molecule formation process has been simulated in full detail, and in our view, it is a very compelling explanation for the observation that molecules are ubiquitous in supermassive black hole winds, which has been one of the major outstanding problems in the field.”

Richings and Faucher-Giguère look forward to the day when their theory can be confirmed by next-generation missions. They predict that new molecules formed by black hole outflows would be brighter in the infrared wavelength than pre-existing molecules. So when the James Webb Space Telescope takes to space in the Spring of 2019, it will be able to map these outflows in detail using its advance IR instruments.

One of the most exciting things about the current era of astronomy is the way new discoveries are shedding light on decades-old mysteries. But when these discoveries lead to theories that offer symmetry to what were once thought to be incongruous pieces of evidence, that’s when things get especially exciting. Basically, it lets us know that we are moving closer to a greater understanding of our Universe!

Further Reading: Northwestern University, MNRAS

Posted on by Matt Williams

Astronomers Find One of the Oldest Stars in the Milky Way

A recent survey has discovered the first stars of the Milky Way. Credit: Gabriel Pérez, SMM (IAC)

According to modern cosmological models, the Universe began in a cataclysm event known as the Big Bang. This took place roughly 13.8 billion years ago, and was followed by a period of expansion and cooling. During that time, the first hydrogen atoms formed as protons and electrons combined and the fundamental forces of physics were born. Then, about 100 million years after the Big Bang, that the first stars and galaxies began to form.

The formation of the first stars was also what allowed for the creation of heavier elements, and therefore the formation of planets and all life as we know it. However, until now, how and when this process took place has been largely theoretical since astronomers did not know where the oldest stars in our galaxy were to be found. But thanks to a new study by a team of Spanish astronomers, we may have just found the oldest star in the Milky Way!

The study, titled “J0815+4729: A chemically primitive dwarf star in the Galactic Halo observed with Gran Telescopio Canarias“, recently appeared in The Astrophysical Journal Letters. Led by David S. Aguado of the Instituto de Astrofisica de Canarias (IAC), the team included members from the University of La Laguna and the Spanish National Research Council (CSIC).

Artist’s impression of the Milky Way Galaxy. Credit: NASA/JPL-Caltech/R. Hurt (SSC-Caltech)

This star is located roughly 7,500 light years from the Sun, and was found in the halo of the Milky Way along the line of sight to the Lynx constellation. Known as J0815+4729, this star is still in its main sequence and has a low mass, (around 0.7 Solar Masses), though the research team estimates that it has a surface temperature that is about 400 degrees hotter – 6,215 K (5942 °C; 10,727 °F) compared to 5778 K (5505 °C; 9940 °F).

For the sake of their study, the team was looking for a star that showed signs of being metal-poor, which would indicate that it has been in its main sequence for a very long time. The team first selected J0815+4729 from the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey (SDSS-III/BOSS) and then conducted follow-up spectroscopic investigations to determine its composition (and hence its age).

This was done using the Intermediate dispersion Spectrograph and Imaging System (ISIS) at the William Herschel Telescope (WHT) and the Optical System for Imaging and low-intermediate-Resolution Integrated Spectroscopy (OSIRIS) at Gran Telescopio de Canarias (GTC), both of which are located at the Observatorio del Roque de los Muchachos on the island of La Palma.

Consistent with what modern theory predicts, the star was found in the Galactic halo – the extended component of our galaxy that reaches beyond the galactic disk (the visible portion). It is in this region that the oldest and most metal-poor stars are believed to be found in galaxies, hence why the team was confident that a star dating back to the early Universe would be found here.

The William Herschel Telescope, part of the Isaac Newton group of telescopes, located on Canary Island. Credit: ing.iac.es

As Jonay González Hernández – a professor from the University of La Laguna, a member of the IAC and a co-author on the paper – explained in an IAC press release:

“Theory predicts that these stars could use material from the first supernovae, whose progenitors were the first massive stars in the galaxy, around 300 million years after the Big Bang. In spite of its age, and its distance away from us, we can still observe it.”

Spectra obtained by both the ISIS and OSIRIS instruments confirmed that the star was poor in metals, indicating that J0815+4729 has only one-millionth of the calcium and iron that the Sun contains. In addition, the team also noticed that the star has a higher carbon content than our Sun, accounting for almost 15% percent of its solar abundance (i.e. the relative abundance of its elements).

In short, J0815+4729 may be the most iron-poor and carbon-rich star currently known to astronomers. Moreover, finding it was rather difficult since the star is both weak in luminosity and was buried within a massive amount of SDSS/BOSS archival data. As Carlos Allende Prieto, another IAC researcher and a co-author on the paper, indicated:

“This star was tucked away in the database of the BOSS project, among a million stellar spectra which we have analysed, requiring a considerable observational and computational effort. It requires high-resolution spectroscopy on large telescopes to detect the in the star, which can help us to understand the first supernovae and their progenitors.”

In the near future, the team predicts that next-generation spectrographs could allow for further research that would reveal more about the star’s chemical abundances. Such instruments include the HORS high-resolution spectrograph, which is presently in a trial phase on the Gran Telescopio Canarias (GTC).

“Detecting lithium gives us crucial information related to Big Bang nucleosynthesis,” said Rafael Rebolo, the director of the IAC and a coauthor of the paper. “We are working on a spectrograph of high-resolution and wide spectral range in order to measure the detailed chemical composition of stars with unique properties such as J0815+4719.”

These future studies are sure to be a boon for astronomers and cosmologists. In addition to being a chance to study stars that formed when the Universe was still in its infancy, they could provide new insight into the early stages of the universe, the formation of the first stars, and the properties of the first supernovae. In other words, they would put us a step closer to know how the Universe as we know it formed and evolved.

Further Reading: IAC, The Astrophysical Journal Letters

Posted on by Matt Williams

Curiosity has Lasted More than 2,000 Days on Mars, Triple its Original Mission Plan

Mosaic image of the Curiosity rover on Mars, which recently turned up more evidence that supports the idea that the planet was once habitability. Credit: NASA/JPL-Caltech/MSSS.

On August 5th, 2012, after spending over 8 months in space, NASA’s Curiosity rover landed on Mars. As part of the NASA Mars Science Laboratory (MSL) mission, and the latest in a series of rovers deployed to the Martian surface, Curiosity had some rather ambitious research goals. In addition to investigating Mars’ climate and geology, the rover was also tasked with revealing more about Mars’ past and determining if it ever supported microbial life.

And recently, the Curiosity rover hit another major milestone in its exploration of the Red Planet. As of January 26th, 2018 the rover has spent a total of 2,000 days on Mars, which works out to 5 years, 5 months and 21 days – or 1947 Martian days (sols). That’s especially impressive when you consider that the mission was only meant to last 687 days (668 sols), or just little under 2 years.

In all that time, the Curiosity rover has accomplished some major feats and has the scars to prove it! Some of it’s wheels have become teared, holed and cracked and its drill has been pushed almost to the point of breaking. And yet, Curiosity is still hard at work pushing itself up a mountain – both literally and figuratively! The rover has also managed to exceed everyone’s expectations.

MRO image of Gale Crater illustrating the landing location and trek of the Rover Curiosity. Credits: NASA/JPL, illustration, T.Reyes

As Ashwin Vasavada, the MSL Project Scientist, told Universe Today via email:

“In terms of challenges, the first 2000 days of Curiosity’s mission went better than I could have hoped. For much of the time, the rover remained as capable as the day it landed. We had a scare in the first year when a memory fault triggered additional problems and nearly resulted in the loss of the mission. We famously wore down our wheels pretty early, as well, but since then we’ve kept that under control. In the last year, we’ve had a major problem with our drill. That’s the only major issue currently, but we believe we’ll be back to drilling in a month or so. If that works out, we’ll amazingly be back to having all systems ready for science!”

As of the penning of this article, the rover is climbing Mount Sharp in order to collect further samples from Mars’ past. Also known as Aeolis Mons, this mountain resides in the center of the Gale Crater where Curiosity landed in 2012 and has been central to Curiosity’s mission. Standing 5,500 meters (18,000 ft) above the valley floor, Mount Sharp is believed to have formed from sediment that was slowly deposited by flowing water over billions of years.

This is all in keeping with current theories about how Mars once had a denser atmosphere and was able to sustain liquid water on its surface. But between 4.2 and 3.7 billion years ago, this atmosphere was slowly stripped away by solar wind, thus turning Mars into the cold and desiccated place that we know today. As a result, the study of Mount Sharp was always expected to reveal a great deal about Mars’ geological evolution.

Image of Mount Sharp taken by the Curiosity rover on Aug. 23rd, 2012. The layers at the base of Mt. Sharp show the geological history of Mars. Credit: NASA/JPL-Caltech/MSSS.

In it’s first year, Curiosity achieved a major milestone when the rover obtained drill samples from low-lying areas that indicated that lakes and streams existed in the Gale Crater between 3.3 to 3.8 billion years ago. In addition, the rover has also obtained ample evidence that the crater once had all the chemical elements and even a chemical source of energy needed for microbial life to exist.

“NASA’s charge to our mission was to determine whether Mars ever had conditions suitable for life,” said Vasavada. “Success was not a foregone conclusion. Would we arrive safely? Would the scientific instruments work? Would the area we chose for the landing site hold the clues we were looking for? For me, meeting each of these objectives are the highlights of the mission. I’ll never forget witnessing the launch, or nervously waiting for a safe touchdown. Discovering an ancient, freshwater lake environment at Gale crater was profound scientifically, but also was the moment that I knew that our team had delivered what we promised to NASA.”

Basically, by scaling Mount Sharp and examining the layers that were deposited over the course of billions of years, Curiosity is able to examine a living geological record of how the planet has evolved since then. Essentially, the lower layers of the mountain are believed to have been deposited 3.5 billion years ago when the Gale Crater was still a lakebed, as evidenced by the fact that they are rich in clay minerals.

The upper layers, meanwhile, are believed to have been deposited over the ensuing millions of years, during which time the lake in the Gale Crater appears to have grown, shrunk, disappeared and then reappeared. Basically, by scaling the mountain and obtaining samples, Curiosity will be able to illustrate how Mars underwent the transition from being a warmer, wetter place to a frozen and dry one.

Image taken of drill sample obtained at the ‘Lubango’ outcrop target on Sol 1320, Apr. 23, 2016. Lubango is located in the Stimson unit on the lower slopes of Mount Sharp inside Gale Crater. Credit: NASA/JPL/MSSS/Ken Kremer/kenkremer.com/Marco Di Lorenzo

As Vasavada explained, this exploration is also key to answering a number of foundational questions about the search for life beyond Earth:

“Curiosity established that Mars was once a suitable home for life; it had liquid water, key chemical building blocks, and energy sources required by life in the lake and groundwater environment within Gale crater. Curiosity also has detected organic molecules in ancient rocks, in spite of all the degradation that could have occurred in three billion years. While Curiosity cannot detect life itself, knowing that Mars can preserve organic molecules bodes well for missions that will explore ancient rocks, looking for signs of past life.”

At this juncture, its not clear how much longer Curiosity will last. Considering that it has already lasted over twice as long as originally intended, it is possible the rover will remain in operation for years to come. However, unlike the Opportunity rover – who’s mission was intended to last for 90 days, but has remained in operation for 5121 days (4984 sols) – Curiosity has a shelf life.

Whereas Opportunity is powered by solar cells, Curiosity is dependent on its Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). Eventually, this slow-fission reactor will exhaust its supply of nuclear fuel and the rover will be forced to come to a halt. And considering how the rover has been put through its paces in the past 5 years, there’s also the chance that it will suffer a mechanical failure.

But in the meantime, there’s plenty of work to be done and lots of opportunities for vital research. As Vasavada put it:

“Curiosity won’t last forever, but in the years we have left, I hope we can complete our traverse through the lowermost strata on Mount Sharp. We’re well over halfway through. There are changes in the composition of the rocks ahead that might tell us how the climate of Mars changed over time, perhaps ending the era of habitability. Every day on Mars still counts, perhaps even more than before. Now every new discovery adds a piece to a puzzle that’s more than halfway done; it reveals more given all the other pieces already around it.”

And be sure to check out this retrospective of the Curiosity rover’s mission, courtesy of NASA:

Further Reading: Forbes, NASA