Hubble Space Telescope view of a plume high in the martian atmosphere seen in May 1997. Credit: NASA/ESA
A curious plume-like feature was observed on Mars on May 17, 1997 by the Hubble Space Telescope. It is similar to the features detected by amateur astronomers in 2012, although appeared in a different location. Credit: JPL/NASA/STScI
Strange plumes in Mars’ atmosphere first recorded by amateur astronomers four year ago have planetary scientists still scratching their heads. But new data from European Space Agency’s orbiting Mars Express points to coronal mass ejections from the Sun as the culprit.
Mystery plume in Mars’ southern hemisphere photographed and animated by amateur astronomer Wayne Jaeschke on March 20, 2012. The feature lasted for about 10 days. Credit: Wayne Jaeschke
On two occasions in 2012 amateurs photographed cloud-like features rising to altitudes of over 155 miles (250 km) above the same region of Mars. By comparison, similar features seen in the past haven’t exceeded 62 miles (100 km). On March 20th of that year, the cloud developed in less than 10 hours, covered an area of up to 620 x 310 miles (1000 x 500 kilometers), and remained visible for around 10 days.
Back then astronomers hypothesized that ice crystals or even dust whirled high into the Martian atmosphere by seasonal winds might be the cause. However, the extreme altitude is far higher than where typical clouds of frozen carbon dioxide and water are thought to be able to form.
Indeed at those altitudes, we’ve entered Mars’ ionosphere, a rarified region where what air there is has been ionized by solar radiation. At Earth, charged particles from the Sun follow the planet’s global magnetic lines of force into the upper atmosphere to spark the aurora borealis. Might the strange features observed be Martian auroras linked to regions on the surface with stronger-than-usual magnetic fields?
Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their tops, auroras can form. Credit: NASA
Once upon a very long time ago, Mars may have had a global magnetic field generated by electrical currents in a liquid iron-nickel core much like the Earth’s does today. In the current era, the Red Planet has only residual fields centered over regions of magnetic rocks in its crust.
The top image shows the location of the mysterious plume on Mars, identified within the yellow circle (top image, south is up), along with different views of the changing plume morphology on March 21, 2012. Copyright: W. Jaeschke and D. Parker
Instead of a single, planet-wide field that funnels particles from the Sun into the atmosphere to generate auroras, Mars is peppered with pockets of magnetism, each potentially capable of connecting with the wind of particles from the Sun to spark a modest display of the “northern lights.” Auroras were first discovered on Mars in 2004 by the Mars Express orbiter, but they’re faint compared to the plumes, which were too bright to be considered auroras.
Still, this was a step in the right direction. What was needed was some hard data of a possible Sun-Earth interaction which scientists ultimately found when they looked into plasma and solar wind measurements collected by Mars Express at the time. David Andrews of the Swedish Institute of Space Physics, lead author of a recent paper reporting the Mars Express results, found evidence for a large coronal mass ejection or CME from the Sun striking the martian atmosphere in the right place and at around the right time.
Earth-based observations of the plume on March 21, 2012 (top right) and of Mars Express solar wind observations during March and April 2012 (bottom right). The left-hand graphics show Mars as seen by Mars Express. Green represents the planet’s dayside and gray, the nightside. Magnetic areas of the crust are shown in blue and red. The white box indicates the area in which the plume observations were made. Together, these graphics show that the amateur observations were made during the martian daytime, along the dawn terminator, while the spacecraft observations were made along the dusk terminator, approximately half a martian ‘day’ later.The black line on Mars is the ground track of the Mars Express orbiter. The plot on the lower right shows Mars Express’s solar wind measurements. The peaks marked by the horizontal blue line indicate the increase in the solar wind properties as a result of the impact of the coronal mass ejection. Credit: Copyright: visual images: D. Parker (large Mars image and bottom inset) & W. Jaeschke (top inset). All other graphics courtesy D. Andrews
CMEs are enormous explosions of hot solar plasma — a soup of electrons and protons — entwined with magnetic fields that blast off the Sun and can touch off geomagnetic storms and auroras when they encounter the Earth and other planets.
“Our plasma observations tell us that there was a space weather event large enough to impact Mars and increase the escape of plasma from the planet’s atmosphere,” said Andrews. Indeed, the plume was seen along the day–night boundary, over a region of known strong crustal magnetic fields.
Locations of 19 auroral detections (white circles) made by Mars Express during 113 nightside orbits between 2004 and 2014, over locations already known to be associated with residual crustal magnetism. The data is superimposed on the magnetic field line structure (from NASA’s Mars Global Surveyor) where red indicates closed magnetic field lines, grading through yellow, green and blue to open field lines in purple. The auroral emissions are very short-lived, they are not seen to repeat in the same locations. Credit: ESA / Copyright Based on data from J-C. Gérard et al (2015)
But again, a Mars aurora wouldn’t be expected to shine so brightly. That’s why Andrews thinks that the CME prompted a disturbance in the ionosphere large enough to affect dust and ice grains below:
“One idea is that a fast-traveling CME causes a significant perturbation in the ionosphere resulting in dust and ice grains residing at high altitudes in the upper atmosphere being pushed around by the ionospheric plasma and magnetic fields, and then lofted to even higher altitudes by electrical charging,” according to Andrews.
A colossal CME, composed of a magnetized cloud of subatomic particles, departs the Sun in February 2000. Credit NASA/ESA/SOHO
With enough dust and ice twinkling high above the planet’s surface, it might be possible for observers on Earth to see the result as a wispy plume of light. Plumes appear to be rare on Mars as a search through the archives has revealed. The only other, seen by the Hubble Space Telescope in May 1997, occurred when a CME was hitting the Earth at the same time. Unfortunately, there’s no information from Mars orbiters at the time about its effect on that planet.
Observers on Earth and orbiters zipping around the Red Planet continue to monitor Mars for recurrences. Scientists also plan to use the webcam on Mars Express for more frequent coverage. Like a dog with a bone, once scientists get a bite on a tasty mystery, they won’t be letting go anytime soon.
An artist's impression of the ancient Martian ocean. When two meteors slammed into Mars 3.4 billion years ago, they triggered massive, 400 ft. tsunamis that reshaped the coastline. Image: ESO/M. Kornmesser, via N. Risinger
About 3.4 billion years ago, (according to a new study) when the Late Heavy Bombardment had ended, and the first cells resembling prokaryotes were appearing on Earth, two enormous meteoroids slammed into the ancient, frigid ocean on Mars. These impacts generated massive 400 ft. high tsunamis that reshaped the shoreline of the Martian ocean, leaving behind fields of sediments and boulders.
It was long thought that ancient Mars had oceans. Sedimentary deposits discovered in the Martian north by radar in 2012 helped make the case for Martian oceans. 3.4 billion years ago, this ocean covered most of the Northern Martian lowlands. It’s thought that the ocean itself was fed by catastrophic flooding, perhaps fuelled by geothermal activity on Mars at the time.
These catastrophic tsunamis would have dwarfed most Earthly disasters. Waves 120 meters high would have swamped landmarks like the Statue of Liberty (93 m. high), and caused enormous destruction along the Martian coastline. If the research behind this new study stands up to scrutiny, then it will help prove the existence of the ancient Martian ocean.
The blue area in the above image is thought to be the location of a primordial ocean Mars. Image: NASA/JPL-Caltech/GSFC – Public Domain
The Martian surface shows the remains of an ancient ocean. In some areas, radar data shows a layer of water-borne sediment on top of a layer of volcanic rock. There’s also evidence of a shoreline, described by some scientists as being like a bathtub ring. The problems is, the shoreline can’t be seen everywhere it should be.
The tsunami hypothesis helps explain this missing shoreline.
According to the new study, led by Alexis Rodriguez, a Mars researcher at the Planetary Science Institute in Tucson Arizona, the tsunamis would have wiped away portions of the coastline, and left behind fields of sediment and boulders, and large backwash channels cut into the Martian surface.
The study is focussed on a specific region on Mars where a highland feature called Arabia Terra abuts the Chryse Planitia lowlands. This area was part of the shoreline of the Martian ocean. In that area, the team behind the study identified two separate geological formations that they say were created by two separate tsunami events.
The top image shows the shoreline of the ancient Martian shoreline at two separate times. The bottom images show debris left behind by the two tsunamis. Image: Alexis Rodriguez.
The first formation, and older of the two, looks every bit like a disturbed shoreline. An enormous wave washed over the beach, and in its wake deposited boulders over 10 meters across. Then, as the water drained back down into the ocean, it cut large backwash channels through its debris and boulder field.
A sequence of zoomed in images of the Martian surface in the study. (A) shows distances and elevations of backwash channels. (B) shows some of the channel-scoured, north-sloping highland mesas in blue. (C) shows the channelled surface, and (D) shows them in closer detail. Finally, (E) is zoomed in to show boulders as much as 10 m. in diameter. (Yellow bars are 10m.) Image: A,B:MOLA Science Team, MSS, JPL, NASA. C,D,E: NASA/JPL/University of Arizona
Then, some time passed. Millions of years, probably, until the second meteor hit, triggering another enormous tsunami. But this one behaved a little differently.
Conditions on Mars had changed by then, with temperatures dropping, and glaciers marching across the landscape, gouging out deep valleys on the surface of Mars. When the second tsunami hit the shore, its effect was different.
This time, the tsunami was more like an icy slurry, according to the team. Because of the cold temperatures, the icy water froze in place in some areas, before it could wash back into the ocean. The result? Deposits of frozen debris formed in dense lobes on the surface.
This long lobe of dark material on the surface of Mars was left behind when a tsunami of icy flush washed over the Martian coastline, freezing in place before it could wash back into the sea. Image: Alexis Rodriquez
But according to Rodriguez, this is just a snapshot of a process that likely occurred multiple times in the history of Mars. Successive meteors could have caused successive mega-tsunamis that would have repeatedly wiped away evidence of a shoreline. This could have happened as often as every 3 million years.
This study isn’t the knockout blow that proves the existence of a Martian ocean in ancient times. But it is certainly intriguing, and is a reasonable hypothesis that explains missing shorelines.
Rodriguez intends to keep looking for other evidence of tsunamis on the Martian surface. If he finds more, it will help make the case for the meteor-tsunami explanation.
Rodriguez will also be visiting places on Earth that are analogues for the Martian surface of ancient times. This summer he plans on visiting high-altitude, cold, alpine lakes in Tibet, where he hopes to learn something about the processes and geological formations involved.
Even better would be a mission to Mars, to sample the area where the tsunamis came ashore. A group of small craters near the shore that were drenched by the tsunamis is of particular interest to Rodriguez and his team. Martian ocean water could have been trapped there for millions of years. This site could provide evidence about the briny nature of the ancient ocean on Mars, and possibly tell us something about the evolution of life there.
An artist's illustration of SpaceX's Dragon capsule entering the Martian atmosphere. Image: SpaceX
A manned mission to Mars is a hot topic in space, and has been for a long time. Most of the talk around it has centred on the required technology, astronaut durability, and the overall feasibility of the mission. But now, some of the talk is focussing on the legal framework behind such a mission.
In April 2016, SpaceX announced their plans for a 2018 mission to Mars. Though astronauts will not be part of the mission, several key technologies will be demonstrated. SpaceX’s Dragon capsule will make the trip to Mars, and will conduct a powered, soft landing on the surface of the red planet. The capsule itself will be launched by another new piece of technology, SpaceX’s Falcon Heavy rocket.
It’s a fascinating development in space exploration; a private space company, in cooperation with NASA, making the trip to Mars with all of its own in-house technology. But above and beyond all of the technological challenges, there is the challenge of making the whole endeavour legal.
Though it’s not widely known or talked about, there are legal implications to launching things into space. In the US, each and every launch by a private company has to have clearance from the Federal Aviation Administration (FAA).
That’s because the US signed the Outer Space Treaty in 1969, a treaty that sets out the obligations and limitations to activities in space. The FAA has routinely given their ascent to commercial launches, but things may be starting to get a little tricky in space.
The most recent Humans To Mars Summit, a conference focussed on Mars missions and explorations, just wrapped up on May 19th. At that conference, George Nield, associate administrator for commercial space transportation at the FAA, addressed the issue. “That’ll be an FAA licensed launch as well,” said Nield of the SpaceX mission to Mars. “We’re already working with SpaceX on that mission,” he added. “There are some interesting policy questions that have to do with the Outer Space Treaty,” said Nield.
The Outer Space Treaty was signed in 1967, and has some sway over space exploration and colonization. Though it gives wide latitude to governments that are exploring space, how it will affect commercial activity like resource exploitation, and installations like settlements in other planets, is not so clear.
An artist’s illustration of a Mars settlement. If a private company like SpaceX were to build a colony on Mars, would other countries cry foul? Image: Bryan Versteeg/MarsOne
According to Nield, the FAA is interested in Article VI of the treaty and how it might impact SpaceX’s planned mission to Mars. Article VI states that all signees to the treaty “shall bear international responsibility for national activities in outer space, including the Moon and other celestial bodies, whether such activities are carried on by governmental agencies or by non-governmental entities.”
Article VI also says, “the activities of non-governmental entities in outer space, including the Moon and other celestial bodies, shall require authorization and continuing supervision by the appropriate State Party to the Treaty.”
What this language means is that the US government itself will bear responsibility for the SpaceX Mars mission. Obviously, this kind of treaty obligation is important. There isn’t exactly a huge list of private companies exploring space, but that will change as the years pass. It seems likely that the bulk of commercial space exploration and resource utilization will be centred in the US, so how the US deals with their treaty obligations will be of immense interest now and in the future.
The treaty itself is mostly focused on avoiding military activity in space. It prohibits things like weapons of mass destruction in space, and weapons testing or military bases on the Moon or other celestial bodies. The treaty also states that the Moon and other planets and bodies cannot be claimed by any nation, and that these and other bodies “are the common heritage of mankind.” Good to know.
Taken as a whole, it’s easy to see why the Treaty is important. Space can’t become a free-for-all like Earth has been in the past. There has to be some kind of framework. “A government needs to oversee these non-governmental activities,” according to Nield.
There’s another aspect to all of this. Governments routinely sign treaties, and then try to figure out ways around them, while hoping their rivals won’t do the same. It’s a sneaky, tactical business, because governments can’t grossly ignore treaties, else the other co-signatories abandon said treaty completely. A case in point is last year’s law, signed by the US Congress, which makes it legal for companies to mine asteroids. This law could be interpreted as violating the Treaty.
The US won the space race against its adversary, the USSR. The image of the American flag planted on the Moon, being saluted by an American astronaut, must have caused great consternation in the Kremlin. Will SpaceX’s mission to Mars cause the same consternation? Will Russia and other nations use the mission to remind the US of their Outer Space Treaty obligations? Image: NASA
Governments can claim, for instance, that their activities are scientific rather than military. Geo-political influence depends greatly on projecting power. If one nation can project power into space, while claiming their activities are scientific rather than military, they will gain an edge over their rivals. Countries also seek to bend the rules of a treaty to satisfy their own interests, while preventing other countries from doing the same. Just look at history.
We’re not in that type of territory yet. So far, no nation has had an opportunity to really violate the treaty, though the asteroid mining law passed by the US Congress comes close.
The SpaceX mission to Mars is a very important one, in terms of how the Outer Space Treaty will be tested and adhered to. More and more countries, and private companies, are becoming space-farers. The legality of increasingly complex missions in space, and the eventual human presence on the Moon and Mars, is a fascinating one not usually addressed by the space science community.
We in the space science community are primarily interested in technological advances, and in the frontiers of human knowledge. It might be time for us to start paying attention to the legal side of things. Space exploration could turn out to have an element of courtroom drama to it.
Mars snapped with the Hubble Space Telescope on May 12 just days before opposition. Credit: NASA/ESA
On May 12, the Hubble Space Telescope took this photo of Mars. Some prominent features of the planet are clearly visible: the ancient and inactive shield volcano Syrtis Major (far right and partly covered by clouds); the heavily eroded Arabia Terra in the center of the image; the dark features of Sinus Sabaeous and Sinus Meridiani below center and the small north polar cap (top).
We’re in store for an exciting weekend as the Earth and Mars get closer to each other than at any time in the last ten years. To take advantage of this special opportunity, the Hubble Space Telescope, normally busy eyeing remote galaxies, was pointed at our next door neighbor to capture this lovely close-up image.
Opposition occurs when Mars and Earth line up on the same side of the Sun. The two planets are closest together around that time. Mars opposition occurs on May 22, when the planet will shine at magnitude -2.0 and with an apparent diameter of 18.6 arc seconds, its largest in over 10 years. Credit: Bob King
As Universe Today writer David Dickinson described in his excellent Mars guide, the planet reaches opposition on Sunday morning May 22. That’s when the planet will be directly opposite the Sun in the sky and rise in the east around the same time the Sun sets in the west. Earth sits squarely in between. Opposition also marks the planet’s close approach to Earth, so that Mars appears bigger and brighter in the sky than usual. A perfect time for detailed studies whether through both amateur and professional telescopes.
Although opposition for most outer planets coincides with the date of closest approach, that’s not true in the case of Mars. If Mars is moving away from the Sun in its orbit when Earth laps it, closest approach occurs a few days before opposition. But if the planet is moving toward the Sun when our planet passes by, closest approach occurs a few days after opposition. This time around, Mars is headed sunward, so the date of closest approach of the two planets occurs on May 30.
It’s all goes back to Mars’ more eccentric orbit, which causes even a few days worth of its orbital travels to make a difference in the distance between the two planets when Earth is nearby. On May 22, Mars will be 47.4 million miles away vs. 46.77 million on the 30th, a difference of about 700,000 miles.
Every 26 months Mars reaches opposition. This mosaic of photos taken by Hubble show seven different oppositions since 1995. Because of Mars’ elliptical orbit, it shows variations in apparent size from opposition to opposition. Mars was the closest in 2003 when it came within 34.8 million miles (56 million kilometer) of Earth. The part of Mars that is tilted towards the Earth also shifts over time, resulting in the changing visibility of the polar caps. Clouds and dust storms, as well as the size of the ice caps, can change the appearance of Mars on time scales of days, weeks, and months. Other features of Mars, such as some of the large dark markings, have remained unchanged for centuries. Credit: NASA/ESA
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On May 12, Hubble took advantage of this favorable alignment and turned its gaze towards Mars to take an image of our rusty-hued neighbor, From this distance the telescope could see Martian features as small as 18.6 miles (30 kilometers) across. The image shows a sharp, natural-color view of Mars and reveals several prominent geological features, from smaller mountains and erosion channels to immense canyons and volcanoes.
Some of the more prominent features in the Hubble photo of Mars are marked here. Limb hazes are visible in modest-sized telescopes as a pale edging around the planet’s rim. The planet’s distinctive red color is created by rust. Billions of years ago, it’s thought that ultraviolet light from the Sun split water in the Martian atmosphere into hydrogen and oxygen. The hydrogen escaped, but the oxygen combined with iron in the planet’s surface rocks to form iron oxide or rust. Many of Earth’s red rock formations are similarly “oxidized.” Credit: NASA/ESA
The orange area in the center of the image is Arabia Terra, a vast upland region. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest features on the planet.
While the polar caps aren’t currently visible, telescope users will be treated to nice views of India-shaped Syrtis Major. The large crater Hellas at the top (south) limb is currently covered in winter clouds. Credit: Christopher Go
South of Arabia Terra, running east to west along the equator, is the long dark feature named Sinus Sabaeus that terminates in a larger, dark blob called and Sinus Meridiani. These darker regions are covered by bedrock from ancient lava flows and other volcanic features. An extended blanket of clouds can be seen over the southern polar cap where it’s late winter. The icy northern polar cap has receded to a comparatively small size because it’s now late summer in the northern hemisphere.
Mars on May 2 shows Syrtis Major off to the east (right). Crossing the top of the photo are Mare Tyrrhenum to the right of the planet’s central meridian and Mare Cimmerium, to the left. Credit: Christopher Go
So the question now is how much will you see as we pull up alongside the Red Planet this weekend? With the naked eye, Mars looks like a fiery “star” in the head of Scorpius the scorpion not far from the similarly-colored Antares, the brightest star in the constellation. It’s unmistakable. Even through the haze it caught my eye last night, rising in the southeast around 10 o’clock with its signature hue.
Through a 4-inch or larger telescope, you can see limb hazes/clouds and prominent dark features such as Syrtis Major, Utopia, clouds over Hellas, Mare Tyrrhenum (to the west of Syrtis Major) and Mare Cimmerium (west of M. Tyrrhenum).
Expert astroimager Damian Peach created this photographic map of Mars labeled with its most prominent features visible in amateur telescopes. Click for a large version. Credit: Damian Peach
These features observers across the America will see this week and early next between about 11 p.m. and 2 a.m. local time. As Mars rotation period is 37 minutes longer than Earth’s, these markings will gradually rotate out of view, and we’ll see the opposite hemisphere in the coming weeks. You can use the map to help you identify particular features or Sky & Telescope’s handy Mars Profilerto know which side of the planet’s visible when.
The Full Moon, Mars only hours before opposition, Saturn and Antares gather in the southern sky for a special, diamond-shaped grouping. Diagram: Bob King, source: Stellarium
To top off all the good stuff happening with Mars, the Full Flower Moon will join up with that planet, Saturn and Antares Saturday night May 21 to create what I like to call a “diamond of celestial lights” visible all night. Don’t miss it!
Italian astronomer Gianluca Masi will offer up two online Mars observing sessions in the coming week, on May 22 and 30, starting at 5 p.m. CDT (22:00 UT). Yet another opportunity to get acquainted with your inner Mars.
Planets and other objects in our Solar System. Credit: NASA.
When we look at beautiful images of the planets of our Solar System, it is important to note that we are looking at is not always accurate. Especially where their appearances are concerned, these representations can sometimes be altered or enhanced. This is a common practice, where filters or color enhancement is employed in order to make sure that the planets and their features are clear and discernible.
So what exactly do the planets of the Solar System look like when we take all the added tricks away? If we were to take pictures of them from space, minus the color enhancement, image touch-ups, and other methods designed to bring out their details, what would their true colors and appearances be? We already know that Earth resembles something of a blue marble, but what about the other ones?
SOFIA in flight, with its telescope exposed. Image: NASA/Jim Ross
Finding atomic oxygen in the Martian atmosphere is very difficult to do, which explains why it’s been 40 years since it was last detected. In the 1970’s, NASA’s Viking and Mariner missions detected Martian atmospheric oxygen, and now, the Stratospheric Observatory for Infrared Astronomy (SOFIA) has detected atomic oxygen in the upper portion of the Martian atmosphere called the mesosphere.
SOFIA is a specially modified Boeing 747 aircraft which carries a 100 inch telescope. It flies at altitudes between 37,000 to 45,000 feet, which puts it above most of the moisture in Earth’s atmosphere. This moisture would otherwise block the infrared radiation that SOFIA “sees.”
“Atomic oxygen in the Martian atmosphere is notoriously difficult to measure,” said Pamela Marcum, SOFIA project scientist. “To observe the far-infrared wavelengths needed to detect atomic oxygen, researchers must be above the majority of Earth’s atmosphere and use highly sensitive instruments, in this case a spectrometer. SOFIA provides both capabilities.”
A close-up of SOFIA’s telescope and primary mirror. Image: NASA/Tom Tschida
A special detector on board SOFIA, the German Receiver for Astronomy at Terahertz Frequencies (GREAT) allowed researchers to distinguish Martian atmospheric oxygen from Earthly oxygen. SOFIA-GREAT only detected half the amount of oxygen that scientists expected to find, which is probably due to changes and variations in the atmosphere. These results were published in a 2015 paper in Astronomy and Astrophysics.
Atomic oxygen has a strong effect on Mars’ atmosphere because it affects how other gases escape the atmosphere. It’s extreme volatility means it bonds with nearby molecules very easily; oxygen will combine with almost all chemical elements, except for the noble gases.
SOFIA is the largest airborne observatory in the world, and is a joint project between NASA and the German Aerospace Center. SOFIA has a 20 year mission timeline. Researchers will continue using SOFIA to study the Martian atmosphere, in order to better understand the variations in oxygen content.
SOFIA is not the only mission with eyes on Mars’ atmosphere. NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) was launched in 2013 to explore the upper atmosphere of Mars, and how it’s affected by the solar wind. It’s thought that Mars’ atmosphere was much thicker in the past, and has been stripped away over time. Atomic oxygen played a role in Mars’ escaping atmosphere in the past, and no doubt will play a role in the future. SOFIA and other missions like MAVEN will hopefully shed some light on Mars’ past and future atmospheres.
Artist's impression of the Earth scorched by our Sun as it enters its Red Giant Branch phase. Credit: Wikimedia Commons/Fsgregs
Since the beginning of human history, people have understood that the Sun is a central part of life as we know it. It’s importance to countless mythological and cosmological systems across the globe is a testament to this. But as our understand of it matured, we came to learn that the Sun was here long before us, and will be here long after we’re gone. Having formed roughly 4.6 bullion years ago, our Sun began its life roughly 40 million years before our Earth had formed.
Since then, the Sun has been in what is known as its Main Sequence, where nuclear fusion in its core causes it to emit energy and light, keeping us here on Earth nourished. This will last for another 4.5 – 5.5 billion years, at which point it will deplete its supply of hydrogen and helium and go through some serious changes. Assuming humanity is still alive and calls Earth home at this time, we may want to consider getting out the way!
The Birth of Our Sun:
The predominant theory on how our Sun and Solar System formed is known as Nebular Theory, which states that the Sun and all the planets began billions of years ago as a giant cloud of molecular gas and dust. Then, approximately 4.57 billion years ago, this cloud experienced gravitational collapse at its center, where anything from a passing star to a shock wave caused by a supernova triggered the process that led to our Sun’s birth.
Basically, this took place after pockets of dust and gas began to collect into denser regions. As these regions pulled in more and more matter, conservation of momentum caused them to begin rotating, while increasing pressure caused them to heat up. Most of the material ended up in a ball at the center while the rest of the matter was flattened out into a large disk that circled around it.
Young stars have a disk of gas and dust around them called a protoplanetary disk. Out of this disk planets are formed, and the presence of water ice in the disc affects where different types of planets form. Credit: NASA/JPL-Caltech
The ball at the center would eventually form the Sun, while the disk of material would form the planets. The Sun then spent the next 100,000 years as a collapsing protostar before temperature and pressures in the interior ignited fusion at its core. The Sun started as a T Tauri star – a wildly active star that blasted out an intense solar wind. And just a few million years later, it settled down into its current form.
Main Sequence:
For the past 4.57 billion years (give or take a day or two), the Sun has been in the Main Sequence of its life. This is characterized by the process where hydrogen fuel, under tremendous pressure and temperatures in its core, is converted into helium. In addition to changing the properties of its constituent matter, this process also produces a tremendous amount of energy. All told, every second, 600 million tons of matter are converted into neutrinos, solar radiation, and roughly 4 x 1027 Watts of energy.
Naturally, this process cannot last forever since it is dependent on the presence of matter which is being regularly consumed. As time goes on and more hydrogen is converted into helium, the core will continue to shrink, allowing the outer layers of the Sun to move closer to the center and experience a stronger gravitational force.
This will place more pressure on the core, which is resisted by a resulting increase in the rate at which fusion occurs. Basically, this means that as the Sun continues to expend hydrogen in its core, the fusion process speeds up and the output of the Sun increases. At present, this is leading to a 1% increase in luminosity every 100 million years, and a 30% increase over the course of the last 4.5 billion years.
The life cycle of a Sun-like star, from its birth on the left side of the frame to its evolution into a red giant on the right after billions of years. Credit: ESO/M. Kornmesser
Approximately 1.1 billion years from now, the Sun will be 10% brighter than it is today. This increase in luminosity will also mean an increase in heat energy, one which the Earth’s atmosphere will absorb. This will trigger a runaway greenhouse effect that is similar to what turned Venus into the terrible hothouse it is today.
In 3.5 billion years, the Sun will be 40% brighter than it is right now, which will cause the oceans to boil, the ice caps to permanently melt, and all water vapor in the atmosphere to be lost to space. Under these conditions, life as we know it will be unable to survive anywhere on the surface, and planet Earth will be fully transformed into another hot, dry world, just like Venus.
Red Giant Phase:
In 5.4 billion years from now, the Sun will enter what is known as the Red Giant phase of its evolution. This will begin once all hydrogen is exhausted in the core and the inert helium ash that has built up there becomes unstable and collapses under its own weight. This will cause the core to heat up and get denser, causing the Sun to grow in size.
It is calculated that the expanding Sun will grow large enough to encompass the orbit’s of Mercury, Venus, and maybe even Earth. Even if the Earth were to survive being consumed, its new proximity to the the intense heat of this red sun would scorch our planet and make it completely impossible for life to survive. However, astronomers have noted that as the Sun expands, the orbit of the planet’s is likely to change as well.
When the Sun reaches this late stage in its stellar evolution, it will lose a tremendous amount of mass through powerful stellar winds. Basically, as it grows, it loses mass, causing the planets to spiral outwards. So the question is, will the expanding Sun overtake the planets spiraling outwards, or will Earth (and maybe even Venus) escape its grasp?
K.-P Schroder and Robert Cannon Smith are two researchers who have addressed this very question. In a research paper entitled “Distant Future of the Sun and Earth Revisted” which appeared in the Monthly Notices of the Royal Astronomical Society, they ran the calculations with the most current models of stellar evolution.
According to Schroder and Smith, when the Sun becomes a red giant star in 7.59 billion years, it will start to lose mass quickly. By the time it reaches its largest radius, 256 times its current size, it will be down to only 67% of its current mass. When the Sun does begin to expand, it will do so quickly, sweeping through the inner Solar System in just 5 million years.
It will then enter its relatively brief (130 million year) helium-burning phase, at which point, it will expand past the orbit of Mercury, and then Venus. By the time it approaches the Earth, it will be losing 4.9 x 1020 tonnes of mass every year (8% the mass of the Earth).
But Will Earth Survive?:
Now this is where things become a bit of a “good news/bad news” situation. The bad news, according to Schroder and Smith, is that the Earth will NOT survive the Sun’s expansion. Even though the Earth could expand to an orbit 50% more distant than where it is today (1.5 AUs), it won’t get the chance. The expanding Sun will engulf the Earth just before it reaches the tip of the red giant phase, and the Sun would still have another 0.25 AU and 500,000 years to grow.
Artist’s impression of a Red giant star. Credit:NASA/ Walt Feimer
Once inside the Sun’s atmosphere, the Earth will collide with particles of gas. Its orbit will decay, and it will spiral inward. If the Earth were just a little further from the Sun right now, at 1.15 AU, it would be able to survive the expansion phase. If we could push our planet out to this distance, we’d also be in business. However, such talk is entirely speculative and in the realm of science fiction at the moment.
And now for the good news. Long before our Sun enters it’s Red Giant phase, its habitable zone (as we know it) will be gone. Astronomers estimate that this zone will expand past the Earth’s orbit in about a billion years. The heating Sun will evaporate the Earth’s oceans away, and then solar radiation will blast away the hydrogen from the water. The Earth will never have oceans again, and it will eventually become molten.
Yeah, that’s the good news… sort of. But the upside to this is that we can say with confidence that humanity will be compelled to leave the nest long before it is engulfed by the Sun. And given the fact that we are dealing with timelines that are far beyond anything we can truly deal with, we can’t even be sure that some other cataclysmic event won’t claim us sooner, or that we wont have moved far past our current evolutionary phase.
An interesting side benefit will be how the changing boundaries of our Sun’s habitable zone will change the Solar System as well. While Earth, at a mere 1.5 AUs, will no longer be within the Sun’s habitable zone, much of the outer Solar System will be. This new habitable zone will stretch from 49.4 AU to 71.4 AU – well into the Kuiper Belt – which means the formerly icy worlds will melt, and liquid water will be present beyond the orbit of Pluto.
Perhaps Eris will be our new homeworld, the dwarf planet of Pluto will be the new Venus, and Haumeau, Makemake, and the rest will be the outer “Solar System”. But what is perhaps most fascinating about all of this is how humans are even tempted to ask “will it still be here in the future” in the first place, especially when that future is billions of years from now.
Somehow, the subjects of what came before us, and what will be here when we’re gone, continue to fascinate us. And when dealing with things like our Sun, the Earth, and the known Universe, it becomes downright necessary. Our existence thus far has been a flash in the pan compared to the cosmos, and how long we will endure remains an open question.
Mars from orbit. Valles Marineris and Volcanic region
Given it’s similarities to Earth, Mars is often referred to as “Earth’s Twin”. Like Earth, Mars is a terrestrial planet, which means it is composed largely of silicate rock and minerals that are differentiated into a core, mantle and crust. It is also located within the Sun’s “Goldilocks Zone” (aka. habitable zone), has polar ice caps, and once had flowing water on its surface. But beyond these, Mars and Earth are very different worlds.
In addition to their stark contrasts in temperature, surface conditions, and exposure to harmful radiation, Mars also takes a significantly longer time to complete a single orbit of the Sun. In fact, a year on Mars is almost twice as long as a year here on Earth – lasting 686.971 days, which works out to about 1.88 Earth years. And in the course of that orbit, the planet undergoes some rather interesting changes.
Designer Jose Fernandez has been hired by SpaceX to design spacesuits. Fernandez has designed many superhero costumes, including the Bat Armor, pictured here in a collectible from Hot Toys. Image: Sideshow Collectibles
Everything about SpaceX seems exciting right now. In April, SpaceX successfully landed their reusable rocket, the Falcon 9, on a droneship at sea. Also in April, SpaceX announced that they intend to send a Dragon capsule to Mars by 2018. Now, Elon Musk’s private space company has hired Jose Fernandez, superhero movie costume designer, to design spacesuits for his astronauts.
Fernandez, with his company Ironhead Studio, has quite a resume when it comes to costume design. He’s designed superhero costumes for movies like Batman vs Superman: Dawn of Justice and Captain America: Civil War. He’s also designed costumes for X-Men movies, for Wonder Woman, Tron, and for The Penguin in Batman Returns.
Spacesuits have been slaves to function for a long time. The extreme environments in space have constrained their design to utilitarian forms, out of necessity. But now that Elon Musk has hired Fernandez, things could change. Considerably.
Jose Fernanzed heads Ironhead Studios, where he and his team create stunning super-hero costumes. Image: Jose Fernandez/Ironhead Studios
Whatever designs Fernandez comes up with, they will still have to have functionality as their primary concern. There’s no escaping that. But having someone with excellent visual design skills will certainly spice things up.
SpaceX had four other companies working on bids for this design work, but in the end it was Fernandez that won. This is no surprise given Fernandez’ long track record of making great costumes for superheroes. Over a twenty year span, he has also created costumes for Wolverine, Spiderman, The Fantastic Four, and Thor. That is an enviable collection of designs.
It will be super interesting to see what Fernandez comes up with, and how design will meld with engineering requirements to create a safe, effective spacesuit. After all, the people wearing them won’t be actors, and they will require the absolute best performance possible.
Purists may scoff at having someone from Hollywood involved in spacesuit design. After all, this is serious business. The surface of Mars is not a movie set, it’s a dangerous, alien world. But there’s no telling what Fernandez will come up with. If his success in movie costumes is any indication, he might convert any nay-sayers into supporters.
The ESA and NASA are also working on new spacesuit designs. The video below is a good discussion of spacesuit design. Compare the blocky, clunky look of the first spacesuits to what astronauts now use.
These dark streaks, called recurring slope lineae (RSL), are on the sloped wall of a crater on Mars. A new study says they may have been formed by boiling water. Credit: NASA/JPL-Caltech/Univ. of Arizona
Finding water on Mars is a primary focus of human efforts to understand the Red Planet. The presence of liquid water on Mars supports the theory that life existed there. Now it looks as though some puzzling features on the surface of Mars could have been caused by boiling water.
Recurring slope lineae (RSL) are dark streaks found on slopes on the surface of Mars. It was thought that these streaks could have been caused by seasonal melting. Other proposed causes were dust avalanches or the venting of carbon dioxide gas. Since the same features are also found on the Moon, they could also be caused by tiny meteorites that cause avalanches. But now a study from researchers at the Open University of England shows that boiling water could have created the patterns.
We don’t have to go looking for thermal vents to find the source of this boiling water. The atmospheric pressure on Mars is so low that any liquid water would boil, without the need for a heat source. At about 1/100th the atmospheric pressure of Earth, Martian water will boil easily.
You don’t have to travel to Mars, or build an atmospheric pressure simulator, to observe the fact that water boils more readily under lower atmospheric pressure. You can see it happen here on Earth. As hikers and mountaineers know from experience, water boils more quickly the higher you go in the mountains. The greater your altitude, the less atmosphere there is pushing down on you, which lowers the boiling point of water. On Mars, that effect is extreme.
The team of researchers, led by M. Masse, performed their experiments in a chamber that can recreate the atmospheric pressure on Mars. Inside the chamber, they built a slope of loose, fine-grained material, and placed a block of ice on it. At first, the team kept the pressure inside the chamber identical to Earth’s atmospheric pressure, and the melting ice had little effect on the slope of loose material.
The ‘Martian Chamber’ used to re-create the atmospheric pressure on Mars. Image: M. Masse
But when they reduced the atmosphere inside the chamber to that of Mars, the water boiled quickly, creating a much more pronounced effect. This vigorous boiling action caused sand grains to fly into the air, creating heaps. As these heaps collapsed, avalanches were triggered. The end result was the same kind of flow patterns observed on Mars.
Numerous other studies have found evidence of liquid water on Mars, and features like the RSL appear to have been caused by water. But though this study seems to add to that growing evidence, it also puts the brakes on the idea that liquid water is present on Mars.
For these RSL to occur on Earth requires a certain amount of water. But because of the ‘boiling water effect’ of the lower pressure atmosphere on Mars, much less water is required to create them. Not only that, but the fact that water boils away so quickly means that any liquid water is short-lived, and would not provide an adequate environment for micro-organisms.
Experimental results from the new study show the effect that the atmospheres of Earth and Mars have on flowing water. Image: M. Masse
Also, the effect that Mars’ lower gravity has on the formation of RSLs is not well understood, and may be another part of the equation. The researchers’ ‘Martian Chamber’ was not built to mimic Mars’ gravity.
These are interesting preliminary results, flawed only by the lack of simulated Martian gravity. For these results to be conclusive, the same process would have to be observed on Mars itself. And that’s not happening anytime soon.
