GOES-17 took this stunning, full-disk snapshot of Earth’s Western Hemisphere from its checkout position at 12:00 p.m. EDT on May 20, 2018, using the Advanced Baseline Imager (ABI) instrument. GOES-17 observes Earth from an equatorial vantage point approximately 22,300 miles above the surface. Credit: NOAA/NASA
The purpose of this new generation of satellites is to improve the forecasts of weather, oceans, the environment and space weather by providing faster and more detailed data, real-time images, and advanced monitoring. Recently, the satellite’s Advanced Baseline Imager (ABI) made its debut by releasing its “first light“, which just happened to be some beautiful and breathtaking images of Earth from space.
The image featured above was taken on May 20th, 2018, where GOES-17 captured the sunset over Earth’s Western Hemisphere. This image was taken when the satellite was at a distance of 35,405 km (22,000 miles) from Earth and was presented in “GeoColor”, which captures features of the Earth’s surface and atmosphere in vivid detail and colors that are familiar to the human eye.
Compared to previous GOES satellites, GOES-17 can collect three times more data at four times the image resolution, and scan the planet five times faster than previous probes. These abilities were put to the test as the ABI created its beautiful images of Earth using two visible bands (blue and red) and one near-infrared “vegetation” band, and one of the ABI’s “longwave” infrared bands.
When combined as a “GeoColor” image, these bands provide valuable information for monitoring dust, haze, smoke, fog, clouds and winds in the atmosphere – which allows meteorologists to monitor and forecast where severe weather events will take place. It also allows scientists to monitor vegetation patterns to see how weather conditions can lead to increased drought or the expansions of greenery.
It also results in pictures depicting Earth in vivid and colorful detail, as you can plainly see! The satellite is currently in its post-launch checkout testing phase, where controllers on Earth are busy calibrating its instruments and systems and validating them for use. The imagery acquired by the ABI is one such example, which served as a preliminary check to ensure that the imaging instrument will function properly.
Other images included the picture of a series of dynamic marine stratocumulus clouds (shown above), which was captured by the satellite’s ABI off the western coast of Chile in the the southeastern Pacific Ocean. Once again, the improved resolution and sensitivity of the GOES-17 allows it to monitor clouds in our atmosphere with amazing detail and clarity.
GOES-17 also captured a deck of low level stratus clouds covering the southern California coast (above) and smoke plumes created by wildfires in central and northern Saskatchewan, Canada (below). These two images were also acquired by the ABI on May 20th, 2018, and demonstrate how effective GOES-17 will be when it comes to monitoring weather patterns, events that can trigger fires (i.e. lighting), and the resulting fires themselves.
Alongside GOES-17, NOAA’s operational geostationary constellation also consists of GOES-16 (operating as GOES-East), GOES-15 (operating as GOES-West), and GOES-14 – operating as the on-orbit spare. This satellite constellation is currently in good working order and is monitoring weather across the US and the planet each day.
While this data is still preliminary and non-operational, it does provide a good preview of what the GOES-17 can do. In the coming years, it and its third and fourth-generation cousins – GOES-T and GOES-U – will allow Earth observers to monitor weather, climate change and natural disasters with far greater detail, allowing for better early warning and response efforts.
To see more full-resolution images from the GOES-17 ABI, go to the NOAA page.
JunoCam took this image during its eleventh close flyby of Jupiter on February 7, 2018. Image credit: NASA / JPL / SwRI / MSSS / David Marriott.
It is a well-known fact among Earth scientists that our planet periodically undergoes major changes in its climate. Over the course of the past 200 million years, our planet has experienced four major geological periods (the Triassic, Jurassic and Cretaceous and Cenozoic) and one major ice age (the Pliocene-Quaternary glaciation), all of which had a drastic impact on plant and animal life, as well as effecting the course of species evolution.
For decades, geologists have also understood that these changes are due in part to gradual shifts in the Earth’s orbit, which are caused by Venus and Jupiter, and repeat regularly every 405,000 years. But it was not until recently that a team of geologists and Earth scientists unearthed the first evidence of these changes – sediments and rock core samples that provide a geological record of how and when these changes took place.
Professor Dennis Kent with part of a 1,700-foot-long rock core obtained from Petrified Forest National Park in Arizona. Credit: Nick Romanenko/Rutgers University
As noted, the idea that Earth experiences periodic changes in its climate (which are related to changes in its orbit) has been understood for almost a century. These changes consist of Milankovitch Cycles, which consist of a 100,000-year cycle in the eccentricity of Earth’s orbit, a 41,000-year cycle in the tilt of Earth’s axis relative to its orbital plane, and a 21,000-year cycle caused by changes in the planet’s axis.
Combined with the 405,000-year swing, which is the result of Venus and Jupiter’s gravitational influence, these shifts cause changes in how much solar energy reaches parts of our planet, which in turn influences Earth’s climate. Based on fossil records, these cycles are also known to have had a profound impact on life on Earth, which likely had an effect on the course of species of evolution. As Prof. Bent explained in a Rutgers Today press release:
“The climate cycles are directly related to how Earth orbits the sun and slight variations in sunlight reaching Earth lead to climate and ecological changes. The Earth’s orbit changes from close to perfectly circular to about 5 percent elongated especially every 405,000 years.”
For the sake of their study, Prof. Kent and his colleagues obtained sediment samples from the Newark basin, a prehistoric lake that spanned most of New Jersey, and a core rock sample from the Chinle Formation in Petrified Forest National Park in Arizona. This core rock measured about 518 meters (1700 feet) long, 6.35 cm (2.5 inches) in diameter, and was dated to the Triassic Period – ca. 202 to 253 million years ago.
Within ancient rocks in Arizona’s Petrified Forest National Park, scientists have identified signs of a regular variation in Earth’s orbit that influences climate. Credit: Kevin Krajick/Lamont-Doherty Earth Observatory
The team then linked reversals in Earth’s magnetic field – where the north and south pole shift – to sediments with and without zircons (minerals with uranium that allow for radioactive dating) as well as to climate cycles in the geological record. What these showed was that the 405,000-years cycle is the most regular astronomical pattern linked to Earth’s annual orbit around the Sun.
The results further indicated that the cycle been stable for hundreds of millions of years and is still active today. As Prof. Kent explained, this constitutes the first verifiable evidence that celestial mechanics have played a historic role in natural shifts in Earth’s climate. As Prof. Kent indicated:
“It’s an astonishing result because this long cycle, which had been predicted from planetary motions through about 50 million years ago, has been confirmed through at least 215 million years ago. Scientists can now link changes in the climate, environment, dinosaurs, mammals and fossils around the world to this 405,000-year cycle in a very precise way.”
Previously, astronomers were able to calculate this cycle reliably back to around 50 million years, but found that the problem became too complex prior to this because too many shifting motions came into play. “There are other, shorter, orbital cycles, but when you look into the past, it’s very difficult to know which one you’re dealing with at any one time, because they change over time,” said Prof. Kent. “The beauty of this one is that it stands alone. It doesn’t change. All the other ones move over it.”
The super-continent Pangaea during the Permian period (300 – 250 million years ago). Credit: NAU Geology/Ron Blakey
In addition, scientists were unable to obtain accurate dates as to when Earth’s magnetic field reversed for 30 million years of the Late Triassic – between ca. 201.3 and 237 million years ago. This was a crucial period for the evolution of terrestrial life because it was when the Supercontinent of Pangaea broke up, and also when the dinosaurs and mammals first appeared.
This break-up led to the formation of the Atlantic Ocean as the continents drifted apart and coincided with a mass extinction event by the end of the period that effected the dinosaurs. With this new evidence, geologists, paleontologists and Earth scientists will be able to develop very precise timelines and accurately categorize fossil evidence dated to this period, which show differences and similarities over wide-ranging areas.
This research, and the ability to create accurate geological and climatological timelines that go back over 200 million years, is sure to have drastic implications. Not only will climate studies benefit from it, but also our understanding of how life, and even how our Solar System, evolved. What emerges from this could include a better understanding of how life could emerge in other star systems.
After all, if our search for extra-solar life life comes down to what we know about life on Earth, knowing more about how it evolved here will better the odds of finding it out there.
Artist's concept of a collision between proto-Earth and Theia, believed to happened 4.5 billion years ago. Credit: NASA
For decades, scientists have pondered how Earth acquired its only satellite, the Moon. Whereas some have argued that it formed from material lost by Earth due to centrifugal force, or was captured by Earth’s gravity, the most widely accepted theory is that the Moon formed roughly 4.5 billion years ago when a Mars-sized object (named Theia) collided with a proto-Earth (aka. the Giant Impact Hypothesis).
However, since the proto-Earth experienced many giant-impacts, several moons are expected to have formed in orbit around it over time. The question thus arises, what happened to these moons? Raising this very question, a team an international team of scientist conducted a study in which they suggest that these “moonlets” could have eventually crashed back into Earth, leaving only the one we see today.
The magnetic field and electric currents in and around Earth generate complex forces that have immeasurable impact on every day life. Credit: ESA/ATG medialab
Earth’s magnetic field is one of the most mysterious features of our planet. It is also essential to life as we know it, ensuring that our atmosphere is not stripped away by solar wind and shielding life on Earth from harmful radiation. For some time, scientists have theorized that it is the result of a dynamo action in our core, where the liquid outer core revolves around the solid inner core and in the opposite direction of the Earth’s rotation.
In addition, Earth’s magnetic field is affected by other factors, such as magnetized rocks in the crust and the flow of the ocean. For this reason, the European Space Agency’s (ESA) Swarm satellites, which have been continually monitoring Earth’s magnetic field since its deployment, recently began monitoring Earth’s oceans – the first results of which were presented at this year’s European Geosciences Union meeting in Vienna, Austria.
The Swarm mission, which consists of three Earth-observation satellites, was launched in 2013 for the sake of providing high-precision and high-resolution measurements of Earth’s magnetic field. The purpose of this mission is not only to determine how Earth’s magnetic field is generated and changing, but also to allow us to learn more about Earth’s composition and interior processes.
Artist’s impression of the ESA’s Swarm satellites, which are designed to measure the magnetic signals from Earth’s core, mantle, crust, oceans, ionosphere and magnetosphere. Credit: ESA/AOES Medialab
Beyond this, another aim of the mission is to increase our knowledge of atmospheric processes and ocean circulation patterns that affect climate and weather. The ocean is also an important subject of study to the Swarm mission because of the small ways in which it contributes to Earth’s magnetic field. Basically, as the ocean’s salty water flows through Earth’s magnetic field, it generates an electric current that induces a magnetic signal.
Because this field is so small, it is extremely difficult to measure. However, the Swarm mission has managed to do just that in remarkable detail. These results, which were presented at the EGU 2018 meeting, were turned into an animation (shown below), which shows how the tidal magnetic signal changes over a 24 hour period.
As you can see, the animation shows temperature changes in the Earth’s oceans over the course of the day, shifting from north to south and ranging from deeper depths to shallower, coastal regions. These changes have a minute effect on Earth’s magnetic field, ranging from 2.5 to -2.5 microtesla. As Nils Olsen, from the Technical University of Denmark, explained in a ESA press release:
“We have used Swarm to measure the magnetic signals of tides from the ocean surface to the seabed, which gives us a truly global picture of how the ocean flows at all depths – and this is new. Since oceans absorb heat from the air, tracking how this heat is being distributed and stored, particularly at depth, is important for understanding our changing climate. In addition, because this tidal magnetic signal also induces a weak magnetic response deep under the seabed, these results will be used to learn more about the electrical properties of Earth’s lithosphere and upper mantle.”
By learning more about Earth’s magnetic field, scientists will able to learn more about Earth’s internal processes, which are essential to life as we know it. This, in turn, will allow us to learn more about the kinds of geological processes that have shaped other planets, as well as determining what other planets could be capable of supporting life.
Be sure to check out this comic that explains how the Swarm mission works, courtesy of the ESA.
The Aurora Station space hotel will launch in 2021 and host its first guests in 2022. It has room for 4 guests and 2 crew. Image: Orion Span
Are you ready for a luxury hotel in space? We all knew it was coming, even though it seems impossibly futuristic. But this time it’s not just science fiction; somebody actually has a plan.
The space hotel will be called “Aurora Station” and the company behind it is Orion Span, a Silicon Valley and Houston-based firm. Orion Span aims to deliver the astronaut experience to people, by delivering the people into space. The catch?
“We developed Aurora Station to provide a turnkey destination in space. Upon launch, Aurora Station goes into service immediately, bringing travelers into space quicker and at a lower price point than ever seen before, while still providing an unforgettable experience” – Frank Bunger, CEO and founder of Orion Span.
First of all, a 12 day stay aboard Aurora Station for two people will cost $19 million US, or $9.5 million per person. Even so, you can’t just buy a ticket and hop on board. Guests must also sign up for three months of Orion Span Astronaut Certification (OSAC). Then they’ll be trained at a facility in Houston, Texas.
So once their cheque has cleared, and once they’re trained, what awaits guests on Aurora Station?
Aurora Station will orbit Earth at 320 km (200 m) and will make the trip around Earth every 90 minutes. If you do the math, that’s 16 sunrises and sunsets each day, and guests will enjoy this slideshow for 12 days. Other than this compressed schedule of 96 sunsets and 96 sunrises during their 12 day stay, guests will also be treated to stunning views of the Earth rolling by underneath them, thanks to the unprecedented number of windows Aurora Station will have.
Aurora Station will have 5600 square feet of living space which can be configured as 2 or 4 suites. Image: Orion Span
Aurora Station is the brain-child of Orion Span’s CEO, Frank Bunger. “We developed Aurora Station to provide a turnkey destination in space. Upon launch, Aurora Station goes into service immediately, bringing travelers into space quicker and at a lower price point than ever seen before, while still providing an unforgettable experience,” said Bunger.
Guests won’t be alone on the station, of course. The space hotel will have room for 6 people in total, meaning 4 guests and 2 crew. (You didn’t think you’d be alone up there, did you?) Each pair of guests will still have some alone time though, in what Orion Span calls luxurious private suites for two.
There’s no doubt that staying on a space hotel for 12 days will be the experience of a lifetime, but still, 12 days is a long time. The space station itself will be 5600 square feet, with two suites that can be configured to four. Each suite will be about the size of a small bedroom. Once you’ve gotten used to seeing Earth below you, and you’re used to your suite, what will you do?
Well, there’ll be Wi-Fi of course. So if you’re the type of person who gets bored of orbiting the only planet that we know of that hosts life, and the only planet on which every human civilization has lived and died on, you can always surf the web or watch videos. Aurora Station will also have a virtual-reality holodeck, the cherry-on-top for this science-fiction-come-to- life space resort.
But apparently, boredom won’t be a problem. In an interview with the Globe and Mail, Orion Span CEO Frank Bunger said, ““We talked to previous space tourists, they said 10 days aboard the space station was not enough.” Maybe the extra 2 days in space that Aurora Station guests will enjoy will be just the right amount.
As far as getting guests to the station, that will be up to other private space companies like SpaceX. SpaceX has plans to send tourists on trips around the Moon, and they have experience docking with the International Space Station, so they should be able to transport guests to and from a space hotel.
Aurora Station will also host micro-gravity research and in-situ manufacturing. Image: Orion Span
It doesn’t seem like there’s any shortage of customers. Aurora Station was introduced on April 5th 2018, and the first four months of reservations sold out within 72 hours, with each guest paying a deposit of $80,000 US.
There’s another side to Aurora Station, though. Other than just a nice get-away for people who can afford it, there’s a research aspect to it. Orion Span will offer Aurora Station as a platform for micro-gravity research on a pay-as-you-go basis. It will also lease capacity for in-situ manufacturing and 3D printing research.
But Aurora Station would hardly be in the news if it was only a research endeavour. What’s got people excited is the ability to visit space. And maybe to own some real estate there.
Orion Span is designing Aurora Station to be expandable. They can attach more stations to the original without disrupting anything. And this leads us to Orion Span’s next goal: space condos.
As it says on Orion Span’s website, “Like a city rising from the ground, this unique architecture enables us to build up Aurora Station in orbit dynamically – on the fly – and with no impact to the remainder of Aurora Station. As we add capacity, we will design in condos available for purchase.”
I think we all knew this would happen eventually. If you have the money, you can visit space, and even own a condo there.
Mining asteroids might be necessary for humanity to expand into the Solar System. But what effect would asteroid mining have on the world's economy? Credit: ESA.
Some might say it’s paranoid to think about an asteroid hitting Earth and wiping us out. But the history of life on Earth shows at least 5 major extinctions. And at least one of them, about 65 million years ago, was caused by an asteroid.
Preparing for an asteroid strike, or rather preparing to prevent one, is rational thinking at its finest. Especially now that we can see all the Near Earth Asteroids (NEAs) out there. The chances of any single asteroid striking Earth may be small, but collectively, with over 15,000 NEAs catalogued by NASA, it may be only a matter of time until one comes for us. In fact, space rocks strike Earth every day, but they’re too small to cause any harm. It’s the ones large enough to do serious damage that concern NASA.
NASA has been thinking about the potential for an asteroid strike on Earth for a long time. They even have an office dedicated to it, called the Office of Planetary Defense, and minds there have been putting a lot of thought into detecting hazardous asteroids, and deflecting or destroying any that pose a threat to Earth.
Computer generated simulation of an asteroid strike on the Earth. Credit: Don Davis/AFP/Getty Images
One of NASA’s proposals for dealing with an incoming asteroid is getting a lot of attention right now. It’s called the Hyper-velocity Asteroid Mitigation Mission for Emergency Response, or HAMMER. HAMMER is just a concept right now, but it’s worth talking about. It involves the use of a nuclear weapon to destroy any asteroid heading our way.
The use of a nuclear weapon to destroy or deflect an asteroid seems a little risky at first glance. They’re really a weapon of last resort here on Earth, because of their potential to wreck the biosphere. But out in space, there is no biosphere. If scientists sound a little glib when talking about HAMMER, the reality is they’re not. It makes perfect sense. In fact, it may be the only sensible use for a nuclear weapon.
The idea behind HAMMER is pretty simple; it’s a spacecraft with an 8.8 ton tip. The tip is either a nuclear weapon, or an 8.8 ton kinetic impactor. Once we detect an asteroid on a collision course with Earth, we use space-based and ground-based systems to ascertain its size. If its small enough, then HAMMER will not require the nuclear option. Just striking a small asteroid with sufficient mass will divert it away from Earth.
If the incoming asteroid is larger, or if we don’t detect it early enough, then the nuclear option is chosen. HAMMER would be launched with an atomic warhead on it, and the incoming offender would be destroyed. It sounds like a pretty tidy solution, but it’s a little more complicated than that.
A lot depends on the size of the object and when it’s detected. If we’re threatened by an object we’ve been aware of for a long time, then we might have a pretty good idea of its size, and of its trajectory. In that case, we can likely divert it with a kinetic impactor.
Artist’s impression of the first interstellar asteroid, “Oumuamua”. This unique object was discovered on 19 October 2017 by the Pan-STARRS 1 telescope in Hawaii. Credit: ESO/M. Kornmesser
But for larger objects, we might require a fleet of impactors already in space, ready to be sent on a collision course. Or we might use the nuclear option. The ER in HAMMER stands for Emergency Response for a reason. If we don’t have enough time to plan or respond, then a system like HAMMER could be built and launched relatively quickly. (In this scenario, relatively quickly means years, not months.)
One of the problems is with the asteroids themselves. They have different orbits and trajectories, and the time to travel to different NEO‘s can vary widely. And things in space aren’t static. We share a region of space with a lot of moving rocks, and their trajectories can change as a result of gravitational interactions with other bodies. Also, as we learned from the arrival of Oumuamua last year, not all threats will be from our own Solar System. Some will take us by surprise. How will we deal with those? Could we deploy HAMMER quickly enough?
Another cautionary factor around using nukes to destroy asteroids is the risk of fracturing them into multiple pieces without destroying them. If an object larger than 1 km in diameter threatened Earth, and we aimed a nuclear warhead at it but didn’t destroy it, what would we do? How would we deal with one or more fragments heading towards Earth?
HAMMER and the whole issue of dealing with threatening asteroids is a complicated business. We’ll have to prepare somehow, and have a plan and systems in place for preventing collisions. But our best bet might lie in better detection.
We’ve gotten a lot better at detecting Near Earth Objects,(NEOs), Potentially Hazardous Objects (PHOs), and Near Earth Asteroids (NEAs) lately. We have telescopes and projects dedicated to cataloguing them, like Pan-STARRS, which discovered Oumuamua. And in the next few years, the Large Synoptic Survey Telescope (LSST) will come online, boosting our detection capabilities even further.
It’s not just extinctions that we need to worry about. Asteroids also have the potential to cause massive climate change, disrupt our geopolitical order, and generally de-stabilize everything going on down here on Earth. At some point in time, an object capable of causing massive damage will speed toward us, and we’ll either need HAMMER, or another system like it, to protect ourselves and the planet.
On February 6th, 2018, SpaceX successfully launched its Falcon Heavy rocket into orbit. This was a momentous occasion for the private aerospace company and represented a major breakthrough for spaceflight. Not only is the Falcon Heavy the most powerful rocket currently in service, it is also the first heavy launch vehicle that relies on reusable boosters (two of which were successfully retrieved after the launch).
Equally interesting was the rocket’s cargo, which consisted of Musk’s cherry-red Tesla Roadster with a spacesuit in the driver’s seat. According to Musk, this vehicle and its “pilot” (Starman), will eventually achieve a Hohmann Transfer Orbit with Mars and remain there for up to a billion years. However, according to a new study, there’s a small chance that the Roadster will collide with Venus or Earth instead in a few eons.
Elon Musk’s Tesla Roadster being loaded aboard the Falcon Heavy’s payload capsule. Credit: SpaceX
As we indicated in a previous post, Musk’s original flight plan has the potential to place the Roadster into a stable orbit around Mars… after a fashion. According to Max Fagin, an aerospace engineer from Colorado and a space camp alumni, the Roadster will get close enough to Mars to establish an orbit by October of 2018. However, this orbit would not rule out close encounters with Earth over the course of the next few million years.
For the sake of their study, Rein and his colleagues considered how such close encounters might alter the Roadster’s orbit in that time. Using data from NASA’s HORIZONS interface to determine the initial positions of all Solar planets and the Roadster, the team calculated the likelihood of future close encounters between the vehicle and the terrestrial planets, and how likely a resulting collision would be.
As they indicated, the Roadster bears some similarities to Near-Earth Asteroids (NEAs) and ejecta from the Earth-Moon system. In short, NEAs permeate the inner Solar System, regularly crossing the orbits of terrestrial planets and experiencing close encounters with them (resulting in the occasional collision). In addition, ejecta from the Earth and Moon also experience close encounters with the terrestrial planets and collide with them.
However, the Tesla Roadster is unique in two key respects: For one, it originated from Earth rather than being pulled from the Asteroid Belt into the inner Solar System by strong resonances. Second, it had a higher ejection velocity when it left Earth, which tends to result in fewer impacts. “Given the peculiar initial conditions and even stranger object, it therefore remains an interesting question to probe its dynamics and eventual fate,” they claim.
The Falcon Heavy Rocket being fired up at launch site LC-39A at NASA’s Kennedy Space Center in Cape Canaveral, Florida. Credit: SpaceX
Another challenge was how the probability of an impact will change drastically over time. While the chance of a collision can be ruled out in the short run (i.e. the next few years), the Roadster’s chaotic orbit is difficult to predict over the course of subsequent close encounters. As such, the team performed a statistical calculation to see how the orbit and velocity of the Roadster would change over time. As they state in their study:
“Given that the Tesla was launched from Earth, the two objects have intersecting orbits and repeatedly undergo close encounters. The bodies reach the same orbital longitude on their synodic timescale of ~2.8 yrs.”
They began by considering how the Roadster’s orbit would evolve over the course of its next 48 orbits, which would encompass the next 1000 years. They then expanded the analysis to consider long-term evolution, which encompassed 240 orbits over the course of the next 3.5 million years. What they found was that on a million-year timescale, the orbit of the Roadster remains in a region dominated by close encounters with Earth.
However, over time, their simulations show that the Roadster will experience changes in eccentricity due to resonant and secular effects. This will result in interactions more frequent interactions between the Roadster and Venus over time, and close encounters with Mars becoming possible. Over long enough timescales, the team even anticipates that interactions with Mercury’s orbit will be possible (though unlikely).
Don’t Panic StarMan, Don’t Panic. Credit: SpaceX
In the end, their simulations revealed that over the course of a million years and beyond, the probability of a collision with a terrestrial planet is unlikely, but not impossible. And while the odds are slim, they favor an eventual collision with Earth. Or as they put it:
“Although there were several close encounters with Mars in our simulations, none of them resulted in a physical collision. We find that there is a ~6% chance that the Tesla will collide with Earth and a ~2.5% chance that it will collide with Venus within the next 1 Myr. The collision rate goes down slightly with time. After 3 Myr the probability of a collision with Earth is ~11%. We observed only one collision with the Sun within 3 Myr.”
Given the Musk hoped that his Roadster would remain in orbit of Mars for one billion years, and that aliens might eventually find it, the prospect of it colliding with Earth or Venus is a bit of a letdown. Why bother sending such a unique payload into space if it’s just going to come back? Still, the odds that it will be drifting through space for millions of years remains a distinct possibility.
And if there are any worries that the Roadster will pose a threat to future missions or Earth itself, consider the message Starman was looking at during his ascent into space – Don’t Panic! Assuming humanity is even alive eons from now, the far greater danger will be that such an antique will burn up in our atmosphere. After millions of years, Starman is sure to be a big celebrity!
The Earth-Moon system, as imaged by NASA's OSIRIS-REx mission. Credit: NASA/OSIRIS-REx team and the University of Arizona
On September 8th, 2016, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission was launched into space. In the coming months, this space probe will approach and then rendezvous with the asteroid 101955 Bennu – a Near-Earth Object (NEO) – for the sake of studying it. The mission will also acquire samples of the asteroid, which will be returned to Earth by 2023.
The OSIRIS-REx mission is an historic one, since it will be the first US spacecraft to conduct a sample-return mission with an asteroid. In the meantime, as the probe has makes its way further into space, it has been providing some truly breathtaking images of the journey. Consider the recently-released composite image of the Earth-Moon system, which NASA created using images that were taken by the probe on October 2nd, 2017.
The images were all taken by the probe’s MapCam instrument, a medium-range camera designed to capture images of outgassing around Bennu and help map its surface in color. On this occasion, it snapped three beautiful pictures of Earth and the Moon. These images were all taken when the spacecraft was at a distance of approximately 5 million km (3 million mi) from Earth – about 13 times the distance between the Earth and the Moon.
Black and white image of Earth taken by the OSIRIS-REx’s NavCam 1 instrument. Credit: NASA/OSIRIS-REx team and the University of Arizona
As part of the OSIRIS-REx Camera Suite (OCAMS), which is operated by researchers at the University of Arizona, the CapCam has four color filters. To produce the image, three of them (b, v and w) were used as a blue, green and red filters and then stacked on top of each other. The Earth and Moon were each color-corrected, and the Moon was brightened to make it more easily visible.
A second image of planet Earth (shown above), was taken on September 22nd, 2017, by one of the probe’s navigational cameras (NavCam 1). As the name suggests, this instrument is intended to help OSIRIS-REx orient itself while making its journey to Bennu and while it studies the asteroid. This is done by tracking starfields in space (while in transit) and landmarks on Bennu’s surface once it has arrived.
The image was taken when OSIRIS-REx was at a distance of 110,000 km (69,000 mi) from Earth. This was just after the probe had completed an Earth gravity-assist maneuver, where it used Earth’s gravitational force to slingshot around its equator and pick up more speed. The original image (shown below) was rotated so that the North Pole would be pointed up and the entire image was enlarged to provide more detail.
As you can see in the altered image, North America is visible on the upper right portion, while Hurricane Maria and the remnants of Hurricane Jose are visible in the far upper-right. The acquisition of these images was the result of painstaking calculations and planning, which were performed in advance by engineers and navigation specialists on the mission team using software called Systems Tool Kit (STK).
Original image taken by the OSIRIS-REx NavCam 1 of Earth. Credit: NASA/Goddard/University of Arizona/Lockheed Martin
These plans were developed to ensure that the probe would be able to snap pictures with precise timing, which were then uploaded to the spacecraft’s computer weeks ahead of time. Within hours of the probe executing its gravity-assist maneuver, crews on the ground were treated to the first images from the spacecraft’s navigational cameras, which confirmed that the probe was following the right path.
The probe is scheduled to reach Bennu in December of 2018, with approach operations commencing this coming August. Bennu is also expected to make a close pass with Earth several centuries from now, and could even collide with us by then. But for the time being, it represents a major opportunity to study the history and evolution of the Solar System, since it is essentially a remnant left over from its formation.
By studying this asteroid up close, and bringing samples back to Earth for further study, the OSRIS-REx mission could help us understand how life began on Earth and where the Solar System as a whole is headed. But in the meantime, the probe has been able to provide us with some beautiful snapshots of Earth, which serve to remind us all of certain things.
Much like Voyager 1‘s “Pale Blue Dot” photo, seeing Earth from space helps to drive home the fact that life is rare and precious. It also reminds us that we, as a species, are all in this together and completely and utterly dependent on our planet and its ecosystems. Once in awhile, we need to be reminded of these things. Otherwise, we might do some stupid – like ruin it!
J. William Schopf and colleagues from UCLA and the University of Wisconsin analyzed the microorganisms with cutting-edge technology called secondary ion mass spectroscopy. Credit: John Vande Wege/UCLA
Life on Earth has had a long and turbulent history. Scientists estimate that roughly 4 billion years ago, just 500 million years after planet Earth formed, the first single-celled lifeforms arose. By the Archean Eon (4 to 2.5 billion years ago), multi-celled lifeforms are believed to have emerged. While the existence of such organisms (Archaea) has been inferred from carbon isotopes found in ancient rocks, fossil evidence has remained elusive.
All of that has changed, thanks to a recent study performed by a team of researchers from UCLA and the University of Wisconsin–Madison. After examining ancient rock samples from Western Australia, the team determined that they contained the fossilized remains of diverse organisms that are 3.465 billion years old. Combined with the recent spate of exoplanet discoveries, this study strengthens the theory that life is plentiful in the Universe.
Apex chert in Western Australia, where the 3.465 billion year old fossils were found. Credit: John Valley/UW-Madison
These 11 fossils were diverse in nature and the researchers divided them into five species groups based on their apparent biological functions. Whereas two of the fossil samples appear to have performed a primitive form of photosynthesis, another apparently produced methane gas. The remaining two appear to have been methane-consumers, which they used to build and maintain their cell walls (much like how mammals use fat).
As J. William Schopf – a professor of paleobiology in the UCLA College and the lead author on the study – indicated in a UCLA Newsroom press release:
“By 3.465 billion years ago, life was already diverse on Earth; that’s clear — primitive photosynthesizers, methane producers, methane users. These are the first data that show the very diverse organisms at that time in Earth’s history, and our previous research has shown that there were sulfur users 3.4 billion years ago as well.
This study, which is the most detailed ever conducted on microorganisms preserved as ancient fossils, builds on work that Schopf and his associates have been performing for over two decades. Back in 1993, Schopf and another team of researchers conducted a study that first described these types of fossils. This was followed in 2002 by another study which substantiated their biological origin.
In this latest study, Schopf and his team established what kind of organisms they are and how complex they are. To do this, they analyzed the microorganisms using a technique called Secondary Ion Mass Spectroscopy (SIMS), which reveals the ratio of carbon-12 to carbon-13. Whereas carbon-12 is stable and the most common type found in nature, carbon-13 is a less common but similarly stable isotope that is used in organic chemistry research.
A microorganism analyzed by the researchers. Credit: J. William Schopf/UCLA
By separating the carbon from each fossil into its constituent isotopes and determining their ratios, the team was able to conclude how long ago the microorganisms lived, as well as how they lived. This task was performed by the Wisconsin researchers, who were led by professor John Valley. “The differences in carbon isotope ratios correlate with their shapes,” said Valley. “Their C-13-to-C-12 ratios are characteristic of biology and metabolic function.”
According to the current scientific consensus, advanced photosynthesis had not yet evolved and oxygen would not appear on Earth until 500 million years later. By 2 billion year ago, concentrations of oxygen gas began increasing rapidly. This means that these fossils, being around roughly 1 billion years after Earth formed, would have lived at a time when their was little oxygen in the atmosphere.
Given that oxygen would be poisonous to these types of primitive photosynthesizers, they are quite rare today. In truth, they can only be found in places where there is sufficient light but no oxygen, something which is rarely found in combination. What’s more, the rocks themselves were a source of great interest since the average lifespan of rock exposed to the surface of Earth is only about 200 million years.
When Shopf first began his career, the oldest-known rock samples were 500 million years old. This means that the fossil-bearing rocks he and his team examined are as old as rocks on Earth can get. To find fossilized life in such ancient samples demonstrates that diverse organisms and a life cycle had already evolved on Earth by the early Archaen Eon, something which scientists only suspected up until this point.
In the future, SIMS technology could be used to look for signs of fossilized life on Mars. Credit: NASA/JPL)
These findings naturally have implications for the study of how and when life emerged on Earth. Beyond Earth, the study also has implications since it demonstrates that life emerged when Earth was still very young and in a primitive state. It is therefore not unlikely that a similar process has been taking place elsewhere in the Universe. As Schopf explained:
“This tells us life had to have begun substantially earlier and it confirms that it was not difficult for primitive life to form and to evolve into more advanced microorganisms. But, if the conditions are right, it looks like life in the universe should be widespread.”
This study was made possible thanks to funding provided by the NASA Astrobiology Institute. Looking to the future, Schopf indicated that the same technology used to date these fossils will likely be used to study rocks brought back by NASA’s crewed mission to Mars. Scheduled for the 2030s, this mission will entail retrieving samples obtained by the Mars 2020 Rover and bringing them back to Earth for analysis.
A new study by an international team of scientists considers whether Mars and Earth formed farther away from the Sun than previously thought. Credit: NASA/JPL-Caltech/USGS
In recent years, astronomers have been looking to refine our understanding of how the Solar System formed. On the one hand, you have the traditional Nebular Hypothesis which argues that the Sun, the planets, and all other objects in the Solar System formed from nebulous material billions of years ago. However, astronomers traditionally assumed that the planets formed in their current orbits, which has since come to be questioned.
This has come to be challenged by theories like the Grand Tack model. This theory states that Jupiter migrated from its original orbit after it formed, which had a big impact on the inner Solar System. And in a more recent study, an international team of scientists have taken things a step further, proposing that Mars actually formed in what is today the Asteroid Belt and migrated closer to the Sun over time.
Composite image showing the size difference between Earth and Mars. Credit: NASA/Mars Exploration
For the sake of their study, the team addressed one of the most glaring issues with traditional models of Solar System formation. This is the assumption that Mars, Earth and Venus formed closely together and that Mars migrated outward to its current orbit. In addition, the theory holds that Mars – roughly 53% as large as Earths and only 15% as massive – is essentially a planetary embryo that never became a full, rocky planet.
However, this has contradicted by bulk elemental and isotopic studies performed on Martian meteorites, which have noted key differences in composition between Mars and Earth. As Brasser and his team indicated in their study:
“This suggests that Mars formed outside of the terrestrial feeding zone during primary accretion. It is therefore probable that Mars always remained significantly farther from the Sun than Earth; its growth was stunted early and its mass remained relatively low.”
To test this hypothesis, the team conducted dynamical simulations that were consistent with the Grand Tack model. In these simulations, Jupiter moved a large concentration of mass towards the Sun at it migrated towards the inner Solar System, which had a profound influence on the formation and orbital characteristics of the terrestrial planets (Mercury, Venus, Earth and Mars).
The theory also holds that this migration pulled material away from Mars, thus accounting for the compositional differences and the planet’s smaller size and mass relative to Venus and Earth. What they found was that in a small percentage of their simulations, Mars formed farther from the Sun and that Jupiter’s gravitational pull pushed Mars into its current orbit.
The Grand Tack model (top) compared to the traditional theories about how the Inner Solar System formed. Credit: Sean Raymond/planetplanet.net
From this, the team concluded that either scientists lack the necessary mechanisms to explain Mars’ formation, or that of all the possibilities, this statistically rare scenario is indeed the correct one. As Stephen Mojzsis – a geological sciences professor at the University of Colorado and a co-author on the study – indicated in a recent interview with Astrobiology Magazine, the fact that the scenario is rare does not make it any less plausible:
“Given enough time, we can expect these events. For example, you’ll eventually get double sixes if you roll the dice enough times. The probability is 1/36 or roughly the same as we get for our simulations of Mars’ formation.”
In truth, a 2% probability (which is what they obtained from the simulations) is hardly poor odds when considered in cosmological terms. And when one considers that such a possibility would allow for the key differences between Mars and its terrestrial cousins (i.e. Earth and Venus), this slim probability appears rather possible. However, the idea that Mars migrated inward during the course of its history also carries with it some serious implications.
For starters, the researchers were pressed to explain how Mars could have possessed a thicker, warmer atmosphere that would have allowed for liquid water to exist on the surface. If Mars actually formed in the modern-day Asteroid Belt, it would have been subject to far less solar flux, and surface temperatures would have been significantly lower than if it had formed in its present-day location.
Scientists were able to gauge the rate of water loss on Mars by measuring the ratio of water and HDO from today and 4.3 billion years ago. Credit: Kevin Gill
However, as they go to indicate, if Mars had enough carbon-dioxide in its early atmosphere, then it is possible that impacts during the Late Heavy Bombardment could have allowed for intermittent periods where liquid water could exist on the surface. Or as they explain it:
“Unless, as our model shows, an intrinsically volatile-rich Mars possessed a strong and sustainable greenhouse atmosphere, its average surface temperature was unremittingly below 0 °C. Such a cold surface environment would have been regularly affected by early impact bombardments that both restarted a moribund hydrological cycle, and provided a haven for possible early life in the martian crust.”
Basically, while Mars would have been subject to less in the way of solar energy during its early lifespan, its possible it could have still been warm enough to support liquid water on its surface. And as Mojzsis stated in a paper he co-authored last year, the many bombardments it received (as attested to by its many craters) would have been enough to melt surface ice, thicken the atmosphere, and trigger a periodic hydrological cycle.
Another interesting thing about this study is how it predicts that Venus likely has a bulk composition (including its oxygen isotopes) that is similar to that of the Earth-Moon system. According to their simulations, this is due to the fact that Venus and Earth always shared the same building blocks, whereas Earth and Mars did not. These findings were consistent with recent ground-based infrared observations of Venus and its atmosphere.
Artist’s impression of the joint NASA-Roscosmos Venera-D mission concept, which wold include a Venus orbiter and a lander designed to survive on Venus’ surface for a few hours. Credit: NASA/JPL-Caltech
But of course, no definitive conclusions can be drawn about that until samples of Venus’ crust can be obtained. This could be accomplished if and when the proposed Venera-Dolgozhivuschaya (Venera-D) mission – a joint NASA/Roscomos plan to send a orbiter and lander to Venus – is launched in the coming decade. In the meantime, there are other outstanding issues in the Grand Tack model and Nebular Hypothesis that need to be addressed.
According to Mojzsis, these include how the gas/ice giants of the Solar System could have formed in their current locations. The idea that they formed in their current orbits beyond the Asteroid Belt seems inconsistent with models of the early Solar System, which show that there was not enough of the necessary material that far from the Sun. An alternative is that they formed closer to the Sun and also migrated outward.
As Mojzsis explained, this possibility is bolstered by recent studies of extra-solar planetary systems, where gas giants have been found to orbit very close to their stars (i.e. “Hot Jupiters”) and farther away:
“We understand from direct observations via the Kepler Space Telescope and earlier studies that giant planet migration is a normal feature of planetary systems. Giant planet formation induces migration, and migration is all about gravity, and these worlds affected each other’s orbits early on.”
If there’s one benefit to being able to look farther out into the Universe, its the way it has allowed astronomers to come up with better and more complete theories of how the Solar System came to be. And as our exploration of the Solar System continues to grow, we are sure to learn many things that will help advance our understanding of other star systems as well.
