Posted on by Matt Williams

What are the Different Masses of the Planets?

Planets and other objects in our Solar System. Credit: NASA.

It is a well known fact that the planets of the Solar System vary considerably in terms of size. For instance, the planets of the inner Solar System are smaller and denser than the gas/ice giants of the outer Solar System. And in some cases, planets can actually be smaller than the largest moons. But a planet’s size is not necessarily proportional to its mass. In the end, how massive a planet is has more to do with its composition and density.

So while a planet like Mercury may be smaller in size than Jupiter’s moon Ganymede or Saturn’s moon Titan, it is more than twice as massive than they are. And while Jupiter is 318 times as massive as Earth, its composition and density mean that it is only 11.21 times Earth’s size. Let’s go over the planet’s one by one and see just how massive they are, shall we?

Mercury:

Mercury is the Solar System’s smallest planet, with an average diameter of 4879 km (3031.67 mi). It is also one of its densest at 5.427 g/cm3, which is second only to Earth. As a terrestrial planet, it is composed of silicate rock and minerals and is differentiated between an iron core and a silicate mantle and crust. But unlike its peers (Venus, Earth and Mars), it has an abnormally large metallic core relative to its crust and mantle.

All told, Mercury’s mass is approximately 0.330 x 1024 kg, which works out to 330,000,000 trillion metric tons (or the equivalent of 0.055 Earths). Combined with its density and size, Mercury has a surface gravity of 3.7 m/s² (or 0.38 g).

Internal structure of Mercury: 1. Crust: 100–300 km thick 2. Mantle: 600 km thick 3. Core: 1,800 km radius. Credit: MASA/JPL
Internal structure of Mercury: 1. Crust: 100–300 km thick 2. Mantle: 600 km thick 3. Core: 1,800 km radius. Credit: MASA/JPL

Venus:

Venus, otherwise known as “Earth’s Sister Planet”, is so-named because of its similarities in composition, size, and mass to our own. Like Earth, Mercury and Mars, it is a terrestrial planet, and hence quite dense. In fact, with a density of 5.243 g/cm³, it is the third densest planet in the Solar System (behind Earth and Mercury). Its average radius is roughly 6,050 km (3759.3 mi), which is the equivalent of 0.95 Earths.

And when it comes to mass, the planet weighs in at a hefty 4.87 x 1024 kg, or 4,870,000,000 trillion metric tons. Not surprisingly, this is the equivalent of 0.815 Earths, making it the second most massive terrestrial planet in the Solar System. Combined with its density and size, this means that Venus also has comparable gravity to Earth – roughly 8.87 m/s², or 0.9 g.

Earth:

Like the other planets of the inner Solar System, Earth is also a terrestrial planet, composed of metals and silicate rocks differentiated between an iron core and a silicate mantle and crust. Of the terrestrial planets, it is the largest and densest, with an average radius of 6,371.0 km (3,958.8 mi) and a mean of density of 5.514 g/cm3.

The Earth's layers, showing the Inner and Outer Core, the Mantle, and Crust. Credit: discovermagazine.com
The Earth’s layers, showing the Inner and Outer Core, the Mantle, and Crust. Credit: discovermagazine.com

And at 5.97 x 1024 kg (which works out to 5,970,000,000,000 trillion metric tons) Earth is the most massive of all the terrestrial planets. Combined with its size and density, Earth experiences the surface gravity that we are all familiar with – 9.8 m/s², or 1 g.

Mars:

Mars is the third largest terrestrial planet, and the second smallest planet in our Solar System. Like the others, it is composed of metals and silicate rocks that are differentiated between a iron core and a silicate mantle and crust. But while it is roughly half the size of Earth (with a mean diameter of 6792 km, or 4220.35 mi), it is only one-tenth as massive.

In short, Mars has a mass of 0.642 x1024 kg, which works out to 642,000,000 trillion metric tons, or roughly 0.11 the mass of Earth. Combined with its size and density – 3.9335 g/cm³ (which is roughly 0.71 times that of Earth’s) – Mars has a surface gravity of 3.711 m/s² (or 0.376 g).

Jupiter:

Jupiter is the largest planet in the Solar System. With a mean diameter of 142,984 km, it is big enough to fit all the other planets (except Saturn) inside itself, and big enough to fit Earth 11.8 times over. But with a mass of 1898 x 1024 kg (or 1,898,000,000,000 trillion metric tons), Jupiter is more massive than all the other planets in the Solar System combined – 2.5 times more massive, to be exact.

upiter's structure and composition. (Image Credit: Kelvinsong CC by S.A. 3.0)
Jupiter’s structure and composition. (Image Credit: Kelvinsong CC by S.A. 3.0)

However, as a gas giant, it has a lower overall density than the terrestrial planets. It’s mean density is 1.326 g/cm, but this increases considerably the further one ventures towards the core. And though Jupiter does not have a true surface, if one were to position themselves within its atmosphere where the pressure is the same as Earth’s at sea level (1 bar), they would experience a gravitational pull of 24.79 m/s2 (2.528 g).

Saturn:

Saturn is the second largest of the gas giants; with a mean diameter of 120,536 km, it is just slightly smaller than Jupiter. However, it is significantly less massive than its Jovian cousin, with a mass of 569 x 1024 kg (or 569,000,000,000 trillion metric tons). Still, this makes Saturn the second most-massive planet in the Solar System, with 95 times the mass of Earth.

Much like Jupiter, Saturn has a low mean density due to its composition. In fact, with an average density of 0.687 g/cm³, Saturn is the only planet in the Solar System that is less dense than water (1 g/cm³).  But of course, like all gas giants, its density increases considerably the further one ventures towards the core. Combined with its size and mass, Saturn has a “surface” gravity that is just slightly higher than Earth’s – 10.44 m/s², or 1.065 g.

Diagram of Saturn's interior. Credit: Kelvinsong/Wikipedia Commons
Diagram of Saturn’s interior. Credit: Kelvinsong/Wikipedia Commons

Uranus:

With a mean diameter of 51,118 km, Uranus is the third largest planet in the Solar System. But with a mass of 86.8 x 1024 kg (86,800,000,000 trillion metric tons) it is the fourth most massive – which is 14.5 times the mass of Earth. This is due to its mean density of 1.271 g/cm3, which is about three quarters of what Neptune’s is. Between its size, mass, and density, Uranus’ gravity works out to 8.69 m/s2, which is 0.886 g.

Neptune:

Neptune is significantly larger than Earth; at 49,528 km, it is about four times Earth’s size. And with a mass of 102 x 1024 kg (or 102,000,000,000 trillion metric tons) it is also more massive – about 17 times more to be exact. This makes Neptune the third most massive planet in the Solar System; while its density is the greatest of any gas giant (1.638 g/cm3). Combined, this works out to a “surface” gravity of 11.15 m/s2 (1.14 g).

As you can see, the planets of the Solar System range considerably in terms of mass. But when you factor in their variations in density, you can see how a planets mass is not always proportionate to its size. In short, while some planets may be a few times larger than others, they are can have many, many times more mass.

We have written many interesting articles about the planets here at Universe. For instance, here’s Interesting Facts About the Solar System, What are the Colors of the Planets?, What are the Signs of the Planets?, How Dense are the Planets?, and What are the Diameters of the Planets?.

For more information, check out Nine Planets overview of the Solar System, NASA’s Solar System Exploration, and use this site to find out what you would weigh on other planets.

Astronomy Cast has episodes on all of the planets. Here’s Episode 49: Mercury to start!

Posted on by Evan Gough

HiRISE Captures Curiosity on the Naukluft Plateau

MSL Curiosity on the Naukluft Plateau on the Martian surface. This image was captured by HiRise on the Mars Reconnaissance Orbiter. Image: NASA/JPL/University of Arizona
MSL Curiosity on the Naukluft Plateau on the Martian surface. This image was captured by HiRise on the Mars Reconnaissance Orbiter. Image: NASA/JPL/University of Arizona

Viewing orbital images of the rovers as they go about their business on the surface of Mars is pretty cool. Besides being of great interest to anyone keen on space in general, they have scientific value as well. New images from the High Resolution Imaging Science Equipment (HiRise) camera aboard the Mars Reconnaissance Orbiter (MRO) help scientists in a number of ways.

Recent images from HiRise show the Mars Science Laboratory (MSL) Curiosity on a feature called the Naukluft Plateau. The Plateau is named after a mountain range in Namibia, and is the site of Curiosity’s 10th and 11th drill targets.

Orbital imagery of the rovers is used to track the activity of sand dunes in the areas the rovers are working in. In this case, the dune field is called the Bagnold Dunes. HiRise imagery allows a detailed look at how dunes change over time, and how any tracks left by the rover are filled in with sand over time. Knowledge of this type of activity is a piece of the puzzle in understanding the Martian surface.

Curiosity on the Naukluft Plateau as captured by HiRise. Image: NASA/JPL/University of Arizona
Curiosity on the Naukluft Plateau as captured by HiRise. Image: NASA/JPL/University of Arizona

But the ability to take such detailed images of the Martian surface has other benefits, as well. Especially as we get nearer to a human presence on Mars.

Orbital imaging is turning exploration on its ear. Throughout human history, exploration required explorers travelling by land and sea to reconnoiter an area, and to draw maps and charts later. We literally had no idea what was around the corner, over the mountain, or across the sea until someone went there. There was no way to choose a location for a settlement until we had walked the ground.

From the serious (SpaceX, NASA) to the fanciful (MarsOne), a human mission to Mars, and an eventual established presence on Mars, is a coming fact. The how and the where are all connected in this venture, and orbital images will be a huge part of choosing where.

Tracking the changes in dunes over time will help inform the choice for human landing sites on Mars. The types and density of sand particles may be determined by monitoring rover tracks as they fill with sand. This may be invaluable information when it comes to designing the types of facilities used on Mars. Critical infrastructure in the form of greenhouses or solar arrays will need to be placed very carefully.

Sci-Fi writers have exaggerated the strength of sand storms on Mars to great effect, but they are real. We know from orbital monitoring, and from rovers, that Martian sandstorms can be very powerful phenomena. Of course, a 100 km/h wind on Earth is much more dangerous than on Mars because of the density of the atmosphere. Martian air is 1% the density of Earth’s, so on Mars the 100 km/h wind wouldn’t do much.

But it can pick up dust, and that dust can foul important equipment. With all this in mind, we can see how these orbital images give us an important understanding of how sand behaves on Mars.

This Martian sandstorm was captured by the MRO's Mars Color Imager instrument. Scientists were monitoring such storms prior to Curiosity's arrival on Mars. Image: NASA/JPL-Caltech/MSSS
This Martian sandstorm was captured by the MRO’s Mars Color Imager instrument. Scientists were monitoring such storms prior to Curiosity’s arrival on Mars. Image: NASA/JPL-Caltech/MSSS

There’s an unpredictability factor to all this too. We can’t always know in advance how important or valuable orbital imagery will be in the future. That’s part of doing science.

But back to the cool factor.

For the rest of us, who aren’t scientists, it’s just plain cool to be able to watch the rovers from above.

And, look at all the Martian eye candy!

These sand dunes in the southern hemisphere of Mars are just starting their seasonal defrost of carbon dioxide. Image: NASA/JPL/University of Arizona
These sand dunes in the southern hemisphere of Mars are just starting their seasonal defrost of carbon dioxide. Image: NASA/JPL/University of Arizona
Posted on by Matt Williams

Time For NASA To Double Down On Journey To Mars

Looking to the future of space exploration, NASA and TopCoder have launched the "High Performance Fast Computing Challenge" to improve the performance of their Pleiades supercomputer. Credit: NASA/MSFC

Since the Authorization Act of 2010, NASA has been pushing ahead with the goal of sending astronauts to Mars by the 2030s. The latter part of this goal has been the subject of much attention in recent years, and for good reason. Sending crewed missions to the Red Planet would be the single-greatest initiative undertaken since the Apollo era, and the rewards equally great.

However, with the scheduled date for a mission approaching, and the upcoming presidential election, NASA is finding itself under pressure to show that they are making headway. Despite progress being made with both the Space Launch System (SLS) and the Orion Multi-Purpose Crew Vehicle, there are lingering issues which need to be worked out before NASA can mount its historic mission to Mars.

One of the biggest issues is that of assigned launched missions that will ensure that the SLS is tested many times before a crewed mission to Mars is mounted. So far, NASA has produced some general plans as part of it’s “Journey to Mars“, an important part of which is the use of the SLS and Orion spacecraft to send a crew beyond low-Earth orbit and explore a near-Earth asteroid by 2025.

NASA's Journey to Mars. NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s. Credit: NASA/JPL
NASA’s Journey to Mars. NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s. Credit: NASA/JPL

This plan is not only intended to provide their astronauts with experience working beyond LEO, but to test the SLS and Orion’s capabilities, not to mention some vital systems – such as Solar Electric Propulsion (SEP), which will be used to send cargo missions to Mars. Another major step is  Exploration Mission 1 (EM-1), the first planned flight of the SLS and the second uncrewed test flight of the Orion spacecraft (which will take place on September 30th, 2018).

However, beyond this, NASA has only one other mission on the books, which is Exploration Mission 2 (EM-2). This mission will involve the crew performing a practice flyby of a captured asteroid in lunar orbit, and which is scheduled for launch in 2023. This will be the first crewed test of the Orion spacecraft, and also the first time American astronauts have left low-Earth orbit since the Apollo 17 mission in 1972.

While significant, these mission remain the only two assigned flights for the SLS and Orion. Beyond these, dozens more have been proposed as part of NASA’s three phase plan to reach Mars. For instance, between 2018 and the 2030s, NASA would be responsible for launching a total of 32 missions in order to send the necessary hardware to near-Mars space before making crewed landings on Phobos and then to Mars.

In accordance with the “Evolvable Mars Campaign” – which was presented last year by NASA’s Human Exploration and Operations Mission Directorate (HEOMD) – Phase One (the “Earth Reliant” phase) of this plan would involve two launches in 2028, which would be responsible for transporting a habitation module, an SEP module, and a exploration vehicle to cis-lunar space.

This would be followed by two SLS flights in 2029, bringing the Trans-Earth Injection (TEI) stage to cis-lunar space, followed by a crew to perform the final checks on the Phobos Hab. By 2030, Phase Two (known as the “Proving Ground” phase) would begin with the last elements – the Earth Orbit Insertion (EOI) stage and taxi elements – being launched to cis-lunar orbit, and then all the equipment being sent to near-Mars space for pre-deployment.

By 2031, two more SLS missions would take place, where a Martian Hab would be launched, followed in 2032 by the launches of the Mars Orbit Insertion (MOI) and Trans-Mars Injection (TMI) stages. By 2033, Phase Three (the “Earth Independent” phase) would begin, where the Phobos crew would be transported to the Transit Hab, followed by the final crewed mission to the Martian surface.

Accomplishing all of this would require that NASA commit to making regular launches over the next few years. Such was the feeling of Bill Gerstenmaier – NASA’s Associate Administrator for Human Exploration and Operations – who recently indicated that NASA will need to mount launches at least once a year to establish a “launch cadence” with the SLS.

Mission proposals of this kind were also discussed at the recent Aerospace Safety Advisory Panel (ASAP) meeting – which meets annually to discuss matters relating to NASA’s safety performance. During the course of the meeting, Bill Hill – the Deputy Associate Administrator for Exploration Systems Development (ESD) in NASA’s Human Exploration and Operations Mission Directorate (HEOMD) – provided an overview of the latest developments in NASA’s planned mission.

The many faces of Mars inner moon, Phobos (Credit: NASA)
The many faces of Mars inner moon, Phobos. Credit: NASA

By and large, the meeting focused on possible concepts for the Mars mission, which included using SEP and chemical propellants for sending hardware to cis-lunar space and near-Mars space, in advance of a mission to Phobos and the Martian surface. Two scenarios were proposed that would rely to these methods to varying extents, both of which called for a total of 32 SLS launches.

However, the outcome of this meeting seemed to indicate that NASA is still thinking over its long-term options and has not yet committed to anything beyond the mission to a near-Earth asteroid. For instance, NASA has indicated that it is laying the groundwork for Phase One of the Mars mission, which calls for flight testing to cis-lunar space.

However, according to Hill, NASA is currently engaged in “Phase 0” of the three phase plan, which involves the use of the ISS to test crew health via long duration space flight. In addition, there are currently no plans for developing Phases Two and Three of the mission. Other problems, such as the Orion spacecraft’s heatshield – which is currently incapable of withstanding the speed of reentry coming all the way from Mar – have yet to be resolved.

Another major issue is that of funding. Thanks to the Obama administration and the passage of the Authorization Act of 2010, NASA has been able to take several crucial steps towards developing their plan for a mission to Mars. However, in order to take things to the next level, the US government will need to show a serious commitment to ensuring that all aspects of the plan get the funding they need.

And given that it is an election year, the budget environment may be changing in the near future. As such, now is the time for the agency to demonstrate that it is fully committed to every phase of its plan to puts boots on the ground of Mars.

On the other hand, NASA has taken some very positive strides in the past six years, and one cannot deny that they are serious about making the mission happen in the time frame it has provided. They are also on track when it comes to proving key concepts and technology.

In the coming years, with flight tests of the SLS and crewed tests of the Orion, they will be even further along. And given the support of both the federal government and the private sector, nothing should stand in the way of human boots touching red soil by the 2030s.

Artist's concept image of a boot print on the moon and on Mars. Credit: NASA/JPL-Caltech
Artist’s concept image of a boot print on the moon and on Mars. Credit: NASA/JPL-Caltech

Further Reading: NASA Spaceflight.com

Posted on by Evan Gough

Mars Stink To Be Duplicated For Earthbound Humans

Thanks to the rovers Spirit, Opportunity, and Curiosity, everyone knows what Mars looks like. But what does it smell like? Image: NASA/JPL-Caltech/MSSS
Thanks to the rovers Spirit, Opportunity, and Curiosity, everyone knows what Mars looks like. But what does it smell like? Image: NASA/JPL-Caltech/MSSS

Intellectual curiosity is a great gift. It’s fulfilling to ponder the great questions of existence: Will the Universe die of heat death after it’s expanded for billions and billions (and billions) more years? Is there something outside of our Universe? What’s on the other side of a black hole?…and…What does Mars smell like?

Seriously.

What may seem to be a frivolous question at first is actually quite interesting once your intellectual curiosity is engaged. The Martian atmosphere itself is much different than Earth’s. Our various robotic visitors to Mars have revealed an atmosphere rich in carbon dioxide (96%). Not much to smell there. But the surface of Mars is also much different than Earth, and contains sulfur, acids, magnesium, iron and chlorine compounds. What might that smell like?

We know that odours have a powerful effect on memory. How might colonists respond to an odour so different from what they’re used to? How might they respond to the odour of Mars once they’ve returned to Earth after a Mars mission? Recreating the smell of Mars for returning colonists might yield interesting results.

The olfactory nerve has a powerful connection to areas of the brain involved in arousal and attention. Can this connection be exploited to help Martian colonists? Image: Patrick J. Lynch CC BY 2.5
The olfactory nerve has a powerful connection to areas of the brain involved in arousal and attention. Can this connection be exploited to help Martian colonists? Image: Patrick J. Lynch CC BY 2.5

Obviously, colonists wouldn’t be breathing the Martian atmosphere. But some essence of Mars would be present in their living quarters, most likely.

After walking on the Moon, Apollo astronauts noticed that they had tracked some Moon dust back into the lander with them. When they removed their helmets, they were able to smell the Moon: a spent gunpowder smell, or a wet ash smell like a campfire that had been put out. The same thing may happen on Mars, no matter how careful people are.

The International Space Station (ISS) has its own particular smell. According to NASA astronaut Don Pettit, the ISS smells like a combined machine shop/engine room/laboratory. But the ISS isn’t a colony, and it isn’t exposed to other worlds. Everything astronauts can smell inside the ISS they can smell back on Earth.

Mars is different. Not just the smell, but because it’s so far away. In the ISS, astronauts can look down and see Earth whenever they want. They can see their country of origin, and see familiar geography. On Mars, none of that is possible. Martians will be dealing with extreme isolation.

How this isolation might affect people spending long periods of time on Mars is an intriguing and important question. And how odors play a part in this is likewise intriguing.

The effects of social isolation are well-understood. It can lead to depression, insomnia, anxiety, fatigue, boredom and emotional instability. These are garden variety problems that everyone faces at some point, but added all together they’re a potent mix that could produce serious mental illness.

Add to that the fact that Martian colonists won’t even be able to see Earth, let alone the fact of the shrunken, pale Sun, and suddenly the psychological burden of colonizing Mars comes into sharper focus. It’ll take a multi-pronged approach to help colonists cope with all of this.

Part of this approach may involve recreating the smell of Mars and exposing colonists to it during their pre-colonization training. And thanks to a technology called “Headspace“, it may be possible to recreate the smell of Mars here on Earth. Spectroscopic measurements of the Martian atmosphere could be relayed back to Earth and the Martian aroma could be recreated in a lab.

Perhaps the smell of Mars can be used prior to departure to help inoculate colonists to some of the hazards of Martian isolation.

Who knows for sure? There may be an interesting revelation hidden in the smell of Mars. How that smell could be used to prepare colonists for their time on Mars, and how returning astronauts respond to the smell of Mars, recreated for them back on Earth, could tell us something important about how our brains work.

Intellectual curiosity says its worth pondering.

Posted on by Fraser Cain

Weekly Space Hangout – June 10, 2016: Dr. Chris McKay

Host: Fraser Cain (@fcain)

Special Guest:
NASA Astrobiologist Dr. Chris McKay organized an August 2014 workshop to discuss the future of a permanent moon base, and the ultimate goal of establishing a human settlement on Mars. The resultant nine papers have been recently published in a special issue of the journal New Space.

Guests:
Paul M. Sutter (pmsutter.com / @PaulMattSutter)
Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg)
Dave Dickinson (www.astroguyz.com / @astroguyz)

Their stories this week:
LISA Pathfinder Exceeds Expectations

Hunting Lunar Letters

Watching a Black Hole Eat – Live!

Inflatable ISS module inflates

Falcon 9 relaunch target slips to Sept/Oct

We’ve had an abundance of news stories for the past few months, and not enough time to get to them all. So we are now using a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!

We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Google+, Universe Today, or the Universe Today YouTube page.

You can also join in the discussion between episodes over at our Weekly Space Hangout Crew group in G+!

Posted on by Evan Gough

These are the 40 Who Might Die on Mars

Mars. A great place to die. Image: NASA, J. Bell (Cornell U.) and M. Wolff (SSI)
Mars. A great place to die. Image: NASA, J. Bell (Cornell U.) and M. Wolff (SSI)

If there were an Olympics for ambition, the Dutch-based non-profit organization Mars One would surely be on the podium.

If you haven’t heard of them, (and we expect you have,) they are the group that plans to send colonists to Mars on a one-way trip, starting in the year 2026. Only 24 colonists will be selected for the dubious distinction of dying on Mars, but that hasn’t stopped 200,000 people from 140 countries from signing up and going through the selection process.

There are 100 people who have made it through the selection process so far. Another five day testing phase will knock that number down to 40, out of which 24 will be chosen as the lucky ones. The latest testing will start soon. According to Mars One, most of their testing is the same as the testing that NASA does on their astronauts.

At least some of the candidates have serious backgrounds. One, Zachary Gallegos, is a geologist and field chemist who works with the Mars Science Laboratory. Here’s what he has to say:

All of this testing and narrowing down is partially funded by a reality show, which adds to the sort of carnival atmosphere around the whole thing, and makes it hard to take it seriously.

But, some people are serious about it.

In a statement, Mars One commented on the upcoming testing:

“Over the course of five days, candidates will face various challenges. It will be the first time all candidates will meet in person and demonstrate their capabilities as a team.”

“In this round the candidates will play an active role in decision making/group formation. Mars One has asked the candidates to group themselves into teams with the people they believe they can work well with.”

A human presence on Mars is a great idea, of course. But it seems fatalistic, and pointless, to choose to die there. And rest assured, these colonists are meant to die there.

Mars One addresses this kind of thinking on their website:

“For anyone not interested to go to Mars, moving permanently to Mars would be the worst kind of punishment. Most people would give an arm and a leg to be allowed to stay on Earth so it is often difficult for them to understand why anyone would want to go.”

“Yet many people apply for Mars One’s mission and these are the people who dream about someday living on Mars. They would give up anything for the opportunity and it is often difficult for them to understand why anyone would not want to go.”

Fair enough. Maybe these are the types of people who really contribute in driving humanity forward.

NASA is planning to get humans to Mars in the 2030s, and Elon Musk says he’ll do it even earlier. But they plan to bring people back. If they can provide return trips, it seems a wasteful sacrifice to die on Mars when they don’t have to. Couldn’t successful colonists contribute a lot to humanity if they were to return to Earth after their successful missions?

Mars One seems to gloss over a lot of problems. Here’s some more from their website:

A new group of four astronauts will land on Mars every two years, steadily increasing the settlement’s size. Eventually, a living unit will be built from local materials, large enough to grow trees.

As more astronauts arrive, the creativity applied to settlement expansion will certainly give way to ideas and innovation that cannot be conceived now. But it can be expected that the human spirit will continue to persevere, and even thrive in this challenging environment.

“A living unit will be built from local materials, large enough to grow trees.” A simple sentence, which obscures so much complexity. Will they mine and refine iron ore? What do they have in mind?

I don’t want to be a Debbie Downer about it. I love the spirit behind the whole thing. But it takes so much rigorous planning and execution to establish a colony on Mars. And money. How will it all work?

In the end, the whole thing is a long shot. Mars One says they have visited and talked to engineering and technological suppliers globally, and that their timeline and planning is based on this feedback. For example, they say they intend to use a Falcon Heavy rocket from SpaceX to launch their ship. But so much detail is left out. The Falcon Heavy doesn’t even exist yet, and Mars One has no control or input into the rocket’s development.

An artist's illustration of the Falcon Heavy. Will it send Mars One colonists to Mars?Image: SpaceX
An artist’s illustration of the Falcon Heavy. Will it send Mars One colonists to Mars?Image: SpaceX

Take a look at the two sentences describing how they will communicate with Earth:

“The communications system will consist of two communications satellites and Earth ground stations. It will transmit data from Mars to Earth and back.”

Does this type of brevity inspire confidence?

For at least 200,000 people, the answer is “yes.”

Posted on by Ken Kremer

Mars at Closest Earth Approach Over SpaceX Recovered Falcon 9 at Sea – Photo

Mars Close Approach over recovered SpaceX Falcon 9 atop droneship at sea on June 1, 2016 as seen from Jetty Park Pier in Port Canaveral, FL. Credit: Ken Kremer/kenkremer.com
Mars Close Approach over recovered SpaceX Falcon 9 atop droneship at sea on June 1, 2016 as seen from Jetty Park Pier in Port Canaveral, FL. Credit: Ken Kremer/kenkremer.com
Mars Close Approach over recovered SpaceX Falcon 9 atop droneship at sea on June 1, 2016 as seen from Jetty Park Pier in Port Canaveral, FL. Credit: Ken Kremer/kenkremer.com

PORT CANAVERAL, FL – As you may have heard its Mars opposition season. What you may not have heard is that Mars made its closest Earth approach high in the Sunshine states nighttime skies coincidentally at the same time as a sea landed SpaceX Falcon 9 was visible just offshore floating on the horizon below.

Rather miraculously this regular natural occurrence of the dance of the planets Earth and Mars making a close embrace as they orbit around our Sun, was taking place simultaneously with a most unnatural event – namely the return of a used SpaceX Falcon 9 landed on a platform at sea that was briefly hugging the Florida coastline.

And better yet you can see them celebrating this first-of-its-kind celestial event together in the photo above of ‘Mars Close Approach over Falcon’ – captured by this author around 11 p.m. EDT on Wednesday, June 1 from the rock wall along Jetty Park Pier in Port Canaveral, Fl.

By sheer coincidence, the Red Planet was making its closest approach to Earth of this orbital cycle just as the most recently launched and recovered SpaceX Falcon 9 first stage booster was arriving just offshore of Cocoa Beach and the Florida Space Coast earlier this week.

As luck would have it, when I ventured out to watch the boosters hoped for nighttime arrival from Jetty Park Pier in Port Canaveral on Wednesday, June 1, I noticed that Mars and the floating Falcon 9 were lined up almost perfectly.

Mars is visible at the head of the large constellation Scorpius.

The Falcon 9 was standing atop the droneship upon which it had landed on May 27 while it was stationed approximately 420 miles (680 kilometers) off shore and east of Cape Canaveral, Florida, surrounded by the vastness of the Atlantic Ocean.

The SpaceX Falcon 9 began its rapid journey to space and back roaring to life at 5:39 p.m. EDT last Friday, May 27, from Space Launch Complex-40 at Cape Canaveral Air Force Station, FL, ascending into sky blue sunshine state skies.

The Falcon 9 was carrying the Thaicom-8 telecommunications satellite to orbit.

On Wednesday night, June 1, Mars was high in the southern night sky, shining brightly almost directly over the spent Falcon 9 booster sailing some 3 miles (5 km) offshore of Cocoa Beach.

Thankfully the weather gods even cooperated by delivering crystal clear nighttime skies.

So with Mars at Opposition and Falcon 9 in view and while awaiting the droneship bringing the booster into Port Canaveral I took some exposure shots of this first totally unique opportunity.

Mars Close Approach took place on May 30, 2016. That is the point in Mars’ orbit when it comes closest to Earth.

The Red Planet was only 46.8 million miles (75.3 million kilometers) from Earth.

“Mars reaches its highest point around midnight — about 35 degrees above the southern horizon, or one third of the distance between the horizon and overhead,” according to a NASA description and the graphic shown below.

Mars closest approach to Earth this cycle is May 30, 2016. That is the point in Mars' orbit when it comes closest to Earth. Mars will be at a distance of 46.8 million miles (75.3 million kilometers). Credit: NASA/JPL-Caltech

Mars closest approach to Earth this cycle is May 30, 2016. That is the point in Mars’ orbit when it comes closest to Earth. Mars will be at a distance of 46.8 million miles (75.3 million kilometers). Credit: NASA/JPL-Caltech

Mars is currently visible for much of the night.

Mars oppositions happen about every 26 months when Mars and the sun are on directly opposite sides of Earth.

The 156 foot tall Falcon 9 booster had landed atop the specially designed SpaceX ‘droneship’ named “Of Course I Still Love You” or “OCISLY” less than 9 minutes after the May 27 blastoff.

Incredible sight of pleasure craft zooming past SpaceX Falcon 9 booster from Thaicom-8 launch on May 27, 2016 as it arrives at the mouth of Port Canaveral, FL, atop droneship platform on June 2, 2016. Credit: Ken Kremer/kenkremer.com
Incredible sight of pleasure craft zooming past SpaceX Falcon 9 booster from Thaicom-8 launch on May 27, 2016 as it arrives at the mouth of Port Canaveral, FL, atop droneship platform on June 2, 2016. Credit: Ken Kremer/kenkremer.com

The Thaicom-8 mission marked the third time SpaceX nailed a booster landing on an ocean going platform.

But unlike the prior two sea landings, this booster came to rest at noticeable tilt.

This caused SpaceX some headaches and concern it might fall over and be destroyed in transit before reaching land.

So the booster didn’t make it back into port Wednesday night as onlookers had hoped. And SpaceX did not announce a return schedule.

It actually would up station keeping and hugging the shoreline for nearly 2 extra days while workers stabilized the booster.

Tow boat passing in front of the used SpaceX rocket waiting offshore. Credit: Julian Leek
Tow boat passing in front of the used SpaceX rocket waiting offshore. Credit: Julian Leek

The 15 story tall spent first stage was secured with multiple tie downs to the droneships deck.

Up close view of base of recovered SpaceX Falcon 9 atop droneship during arrival on June 2, 2016. Credit: Ken Kremer/kenkremer.com
Up close view of base of recovered SpaceX Falcon 9 atop droneship during arrival on June 2, 2016 shows ties down securing booster to deck. Credit: Ken Kremer/kenkremer.com

As I witnessed and reported here, the booster finally sailed triumphantly into the mouth of Port Canaveral around lunchtime on Thursday, June 2.

SpaceX Falcon 9 booster moving along the Port Canaveral channel atop droneship platform with cruise ship in background nears ground docking facility on June 2, 2016 following Thaicom-8 launch on May 27, 2016. Credit: Ken Kremer/kenkremer.com
SpaceX Falcon 9 booster moving along the Port Canaveral channel atop droneship platform with cruise ship in background nears ground docking facility on June 2, 2016 following Thaicom-8 launch on May 27, 2016. Credit: Ken Kremer/kenkremer.com

Mars and the recovered Falcon 9 actually tie in rather neatly.

The SpaceX rockets launch and recovery technology are all being developed so they will one day lead to establishing a ‘City on Mars’ – according to the SpaceX’s visionary CEO and founder Elon Musk.

Musk aims to radically slash the cost of launching future rockets by recycling them and using them to launch new payloads for new paying customers.

Musk hopes to launch humans to Mars by the mid-2020s.

And this author is also a well known Mars lover.

NASA’s Opportunity rover discovers a beautiful Martian dust devil moving across the floor of Endeavour crater as wheel tracks show robots path today exploring the steepest ever slopes of the 13 year long mission, in search of water altered minerals at Knudsen Ridge inside Marathon Valley on 1 April 2016. This navcam camera photo mosaic was assembled from raw images taken on Sol 4332 (1 April 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
NASA’s Opportunity rover discovers a beautiful Martian dust devil moving across the floor of Endeavour crater as wheel tracks show robots path today exploring the steepest ever slopes of the 13 year long mission, in search of water altered minerals at Knudsen Ridge inside Marathon Valley on 1 April 2016. This navcam camera photo mosaic was assembled from raw images taken on Sol 4332 (1 April 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo

Watch for Ken’s continuing on site reports direct from Cape Canaveral and the SpaceX launch pad.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

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Learn more about SpaceX Falcon 9 rocket, ULA Atlas rocket, Orbital ATK Cygnus, ISS, Boeing, Space Taxis, Mars rovers, Orion, SLS, Antares, NASA missions and more at Ken’s upcoming outreach events:

June 8/9: “SpaceX, ULA, SLS, Orion, Commercial crew, Curiosity explores Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings

Posted on by Evan Gough

Elon Musk Is Sending Humans To Mars In 2024

Elon Musk has announced ambitious plans to send humans to Mars by 2024. Image: Artist's drawing of the Dragon capsule at Mars. SpaceX.
Elon Musk has announced ambitious plans to send humans to Mars by 2024. Image: Artist's drawing of the Dragon capsule at Mars. SpaceX.

Do you get the feeling that Elon Musk likes making bold announcements?

Every space enthusiast’s favorite billionaire-turned-space-entrepreneur has just announced that he hopes his company, SpaceX, will send humans to Mars in 2024. If this sounds outrageous, you’re not keeping up with developments in commercial space. If this sounds a little bit ambitious, you’re probably right. But ambition is what Musk is all about.

“I think, if things go according to plan, we should be able to launch people probably in 2024, with arrival in 2025,” Musk said.

Musk, of course, is the Paypal co-founder who went on to start the Tesla electric car company, and SpaceX, the private space company. SpaceX has achieved a lot in its short time, including developing the Falcon re-usable rocket and the Dragon delivery and re-supply craft. With an even more powerful rocket in development, the Falcon Heavy, it’s fair to say that Musk has a track record of delivering on ambitious projects.

Musk’s announcement, at the Code Conference 2016 in Los Angeles, is definitely exciting news. It comes on the heels of an announcement earlier this spring stating that SpaceX will send a Dragon capsule to Mars in 2018, albeit one with no personnel on board. Musk founded SpaceX in 2002 with the goal of advancing the technologies required to establish a human colony on Mars, so everything seems to be going according to plan.

But a colony needs supplies, and with that in mind Musk also announced the intention of sending a craft to Mars every two years, in order to establish a supply line.

“The basic game plan is we’re going to send a mission to Mars with every Mars opportunity from 2018 onwards,” Musk said Wednesday night. “They occur approximately every 26 months. We’re establishing cargo flights to Mars that people can count on for cargo.”

“That’s what’s necessary to create a self-sustaining, or a growing, city on Mars,” he added.

Of course, there’s lots of work to be done yet. Currently, there is no rocket powerful enough for a mission like this. The most powerful rocket ever built was the Saturn V, used to get the Apollo mission to the Moon. That was 50 years ago.

An artist's interpretation of NASA's Space Launch System Block 1 configuration with an Orion vehicle. Image: NASA
An artist’s interpretation of NASA’s Space Launch System Block 1 configuration with an Orion vehicle. Image: NASA

NASA’s Space Launch System will have the power for a Mars mission, but that’s a ways away, and they probably won’t be giving SpaceX one. SpaceX has developed the Falcon rocket, and are working on the Falcon Heavy, but it won’t be enough to establish and maintain a presence on Mars. Still, this obstacle is anything but insurmountable, even though there has been no announcement on the building of this required rocket.

This whole endeavour will be enormously expensive, of course. But with a growing customer base for SpaceX, including the US military, NASA, and commercial communications customers, it seems like the money will be there.

As for the timeline, Musk acknowledges that it is a fairly aggressive one. “When I cite a schedule, it’s actually a schedule I think is true,” Musk said. “It’s not some fake schedule I don’t think is true. I may be delusional. That is entirely possible, and maybe it’s happened from time to time, but it’s never some knowingly fake deadline ever.”

The announcement itself sounds so simple. But Musk knows, as does everyone else involved in planning these kinds of missions, that there is an enormous amount of complex detail behind it all. The food required, the energy needed, and all of the other things that a sustained human presence on Mars will require in order to succeed, are all waiting to be addressed. Musk plans to address some of these details in September at the International Astronautical Congress in Guadalajara, Mexico.

We've been dreaming about a Mars colony for a long time, as this lovely retro drawing shows. Will SpaceX finally give us one? Image: NASA
We’ve been dreaming about a Mars colony for a long time, as the lovely retro drawing shows. Will SpaceX finally give us one? Image: NASA

Musk generates a lot of headlines when he makes these announcements. That’s as it should be. But there are other plans to reach Mars, too.

NASA is planning to get to Mars, but they’re going about it differently. They plan on using their SLS and the Orion to explore what’s called cis-lunar space, near the Moon, to test deep space operations, life support systems, solar-electric thrusters, and habitats. All of this activity could start as soon as 2021, and would support an eventual round-trip mission to Mars in the 2030s.

For a long time, it seemed that a mission to Mars was out of reach, off the table, and nobody was really talking about it. Now, we have two separate programs aiming toward an eventual mission to Mars.

Could this be the new space race? But instead of capitalism versus communism, as in the original space race, it’s government versus private?

In the end, it won’t really matter. We just want someone to get there. And we want an established presence. A colony.

Our survival may depend on it.

Posted on by Evan Gough

Mars At Closest Point To Earth in 11 Years May 30, 2016

Mars in all its red-hued glory. Image: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (ASU), and M. Wolff (Space Science Institute)
Mars in all its red-hued glory. Image: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Bell (ASU), and M. Wolff (Space Science Institute)

If you have a telescope, (What?! You don’t have one?) you’re in for a visual treat tonight. Mars will be at its closest point to Earth in 11 years on May 30. This event is worth checking out, whether with a telescope, astronomy binoculars, or online.

While today is when Mars is at its closest, you actually have a couple weeks to check this out, as the distance between Mars and Earth gradually becomes greater and greater. Today, Mars is 76 million kilometers (47.2 million miles) away, but up until June 12th it will still be no further than 77 million kilometers (48 million miles) away.

The furthest Mars can be from Earth is 401 million kilometers (249 million miles), when the two planets are on the opposite side of the Sun from each other.

For most of us with backyard ‘scopes, it’s difficult to make out much detail. You can see Mars, and at the most you can make out a polar cap. But it’s still fascinating knowing you’re looking at another planet, one that was totally unknowable for most humans who preceded us. A planet that we have rovers on, and that we have several craft in orbit around.

If you don’t have a scope, have no fear. There will be a flood of great astro-photos of Mars in the next few days. There are also options for live streaming feeds from powerful Earth-based telescopes.

The last time Mars was this close to Earth was 2005. A couple years before, the distance shrank to 55.7 million km (34.6 million miles.) That was the closest Mars and Earth have been in several thousand years. In 2018, the two planets will be nearly that close again.

This event is often called “opposition”, but it’s actually more correctly called “closest approach.” Opposition occurs a couple weeks before closest approach, when Mars is directly opposite the Sun.

A top-down image of the orbits of Earth and Mars. Image: NASA
A top-down image of the orbits of Earth and Mars. Image: NASA

But whether you call it opposition, or closest approach, the event itself is significant for more than just looking at it. Missions to Mars are planned when the two planets are close to each other. This reduces mission times drastically.

Mars Express, the mission being conducted by the European Space Agency (ESA) was launched in 2003, when the two planets were as close to each other as they’ve been in thousands of years. All missions to Mars can’t be so lucky, but they all strive to take advantage of the orbital cycles of the two planets, by nailing launch dates that work in our favour.

As for finding Mars in the night sky, it’s not that difficult. If you have clear skies where you are, Mars will appear as a bright, fire-yellow star.
“Just look southeast after the end of twilight, and you can’t miss it,” says Alan MacRobert, a senior editor of Sky & Telescope magazine, in a statement. “Mars looks almost scary now, compared to how it normally looks in the sky.”

This image shows how Mars appears at different times of the year in a typical backyard telescope. Image: NASA/JPL-Caltech
This image shows how Mars appears at different times of the year in a typical backyard telescope. Image: NASA/JPL-Caltech

Although Mars is the closest thing in the sky to Earth right now, other than the Moon, it isn’t the brightest thing in the night sky. That honour is reserved for Jupiter, even though it’s ten times further away. Jupiter is twenty times larger in diameter than Mars, so it reflects much more sunlight and appears much brighter. (Obviously, everything in the night sky pales in comparison to the Moon.)

The reason for such a variation in distances between the planets lies in their elliptical orbits around the Sun. There’s a great video showing how their orbits change the distance between the two planets, here.

If you don’t have a telescope, you can still check Mars out. Go to slooh.com to check out live feeds from a proper telescope.

Posted on by Matt Williams

The Orbit of Mars. How Long is a Year on Mars?

Mosaic of the Valles Marineris hemisphere of Mars, similar to what one would see from orbital distance of 2500 km. Credit: NASA/JPL-Caltech

Mars and Earth have quite a few things in common. Both are terrestrial planets, both are located within the Sun’s habitable zone, both have polar ice caps, similarly tilted axes, and similar variations in temperature. And according to some of the latest scientific data obtained by rovers and atmospheric probes, it is now known that Mars once had a dense atmosphere and was covered with warm, flowing water.

But when it comes to things like the length of a year, and the length of seasons, Mars and Earth are quite different. Compared to Earth, a year on Mars lasts almost twice as long – 686.98 Earth days. This is due to the fact that Mars is significantly farther from the Sun and its orbital period (the time it takes to orbit the Sun) is significantly greater than that of Earth’s.

Orbital Period:

Mars average distance (semi-major axis) from the Sun is 227,939,200 km (141,634,852.46 mi) which is roughly one and half times the distance between the Earth and the Sun (1.52 AU). Compared to Earth, its orbit is also rather eccentric (0.0934 vs. 0.0167), ranging from 206.7 million km (128,437,425.435 mi; 1.3814 AU) at perihelion to 249.2 million km (154,845,701 mi; 1.666 AU) at aphelion. At this distance, and with an orbital speed of 24.077 km/s, Mars takes 686.971 Earth days, the equivalent of 1.88 Earth years, to complete a orbit around the Sun.

The eccentricity in Mars' orbit means that it is . Credit: NASA
The eccentricity in Mars’ orbit means that it is . Credit: NASA

This eccentricity is one of the most pronounced in the Solar System, with only Mercury having a greater one (0.205). However, this wasn’t always the case. Roughly 1.35 million years ago, Mars had an eccentricity of just 0.002, making its orbit nearly circular. It reached a minimum eccentricity of 0.079 some 19,000 years ago, and will peak at about 0.105 in about 24,000 years from now.

But for the last 35,000 years, the orbit of Mars has been getting slightly more eccentric because of the gravitational effects of the other planets. The closest distance between Earth and Mars will continue to mildly decrease for the next 25,000 years. And in about 1,000,000 years from now, its eccentricity will once again be close to what it is now – with an estimated eccentricity of 0.01.

Earth Days vs. Martian “Sols”:

Whereas a year on Mars is significantly longer than a year on Earth, the difference between an day on Earth and a Martian day (aka. “Sol”) is not significant. For starters, Mars takes 24 hours 37 minutes and 22 seconds to complete a single rotation on its axis (aka. a sidereal day), where Earth takes just slightly less (23 hours, 56 minutes and 4.1 seconds).

On the other hand, it takes 24 hours, 39 minutes, and 35 seconds for the Sun to appear in the same spot in the sky above Mars (aka. a solar day), compared to the 24 hour solar day we experience here on Earth. This means that, based on the length of a Martian day, a Martian year works out to 668.5991 Sols.

The Opportunity rover captured this analemma showing the Sun's movements over one Martian year. Images taken every third sol (Martian day) between July, 16, 2006 and June 2, 2008. Credit: NASA/JPL/Cornell/ASU/TAMU
The Opportunity rover captured this analemma showing the Sun’s movements over one Martian year. Images taken every third sol (Martian day) between July, 16, 2006 and June 2, 2008. Credit: NASA/JPL/Cornell/ASU/TAMU

Seasonal Variations:

Mars also has a seasonal cycle that is similar to that of Earth’s. This is due in part to the fact that Mars also has a tilted axis, which is inclined 25.19° to its orbital plane (compared to Earth’s axial tilt of approx. 23.44°). It’s also due to Mars orbital eccentricity, which means it will periodically receive less in the way of the Sun’s radiance during at one time of the year than another. This change in distance causes significant variations in temperature.

While the planet’s average temperature is -46 °C (51 °F), this ranges from a low of -143 °C (-225.4 °F) during the winter at the poles to a high of 35 °C (95 °F) during summer and midday at the equator. This works out to a variation in average surface temperature that is quite similar to Earth’s – a difference of 178 °C (320.4 °F) versus 145.9 °C (262.5 °F). This high in temperatures is also what allows for liquid water to still flow (albeit intermittently) on the surface of Mars.

In addition, Mars’ eccentricity means that it travels more slowly in its orbit when it is further from the Sun, and more quickly when it is closer (as stated in Kepler’s Three Laws of Planetary Motion). Mars’ aphelion coincides with Spring in its northern hemisphere, which makes it the longest season on the planet – lasting roughly 7 Earth months. Summer is second longest, lasting six months, while Fall and Winter last 5.3 and just over 4 months, respectively.

Artist's impression of the seasons on Mars. Credit: britannica.com
Artist’s impression of the seasons on Mars. Credit: britannica.com

In the south, the length of the seasons is only slightly different. Mars is near perihelion when it is summer in the southern hemisphere and winter in the north, and near aphelion when it is winter in the southern hemisphere and summer in the north. As a result, the seasons in the southern hemisphere are more extreme and the seasons in the northern are milder. The summer temperatures in the south can be up to 30 K (30 °C; 54 °F) warmer than the equivalent summer temperatures in the north.

Weather Patterns:

These seasonal variations allow Mars to experience some extremes in weather. Most notably, Mars has the largest dust storms in the Solar System. These can vary from a storm over a small area to gigantic storms (thousands of km in diameter) that cover the entire planet and obscure the surface from view. They tend to occur when Mars is closest to the Sun, and have been shown to increase the global temperature.

The first mission to notice this was the Mariner 9 orbiter, which was the first spacecraft to orbit Mars in 1971, it sent pictures back to Earth of a world consumed in haze. The entire planet was covered by a dust storm so massive that only Olympus Mons, the giant Martian volcano that measures 24 km high, could be seen above the clouds. This storm lasted for a full month, and delayed Mariner 9‘s attempts to photograph the planet in detail.

And then on June 9th, 2001, the Hubble Space Telescope spotted a dust storm in the Hellas Basin on Mars. By July, the storm had died down, but then grew again to become the largest storm in 25 years. So big was the storm that amateur astronomers using small telescopes were able to see it from Earth. And the cloud raised the temperature of the frigid Martian atmosphere by a stunning 30° Celsius.

These storms tend to occur when Mars is closest to the Sun, and are the result of temperatures rising and triggering changes in the air and soil. As the soil dries, it becomes more easily picked up by air currents, which are caused by pressure changes due to increased heat. The dust storms cause temperatures to rise even further, leading to Mars’ experiencing its own greenhouse effect.

Given the differences in seasons and day length, one is left to wonder if a standard Martian calendar could ever be developed. In truth, it could, but it would be a bit of a challenge. For one, a Martian calendar would have to account for Mars’ peculiar astronomical cycles, and our own non-astronomical cycles like the 7-day week work with them.

Another consideration in designing a calendar is accounting for the fractional number of days in a year. Earth’s year is 365.24219 days long, and so calendar years contain either 365 or 366 days accordingly. Such a formula would need to be developed to account for the 668.5921-sol Martian year. All of this will certainly become an issue as human beings become more and more committed to exploring (and perhaps colonizing) the Red Planet.

We have written many interesting articles about Mars here at Universe Today. Here’s How Long is a Year on the Other Planets?, Which Planet has the Longest Day?, How Long is a Year on Mercury, How Long is a Year on Earth?, How Long is a Year on Venus?, How Long is a Year on Jupiter?, How Long is a Year on Saturn?, How Long is a Year on Uranus?, How Long is a Year on Neptune?, How Long is a Year on Pluto?

For more information, check out NASA’s Solar System Exploration page on Mars.

Astronomy Cast also has several interesting episodes on the subject. Like Episode 52: Mars, and Episode 91: The Search for Water on Mars.