There are two amazing events coming up that you’re going to want to watch: the May 20th Annular Eclipse, and the June 5/6 Venus Transit. If you want to watch these spectacles with your own eyes, you need to protect your vision from the burning ball of plasma in the sky – get a pair of Eclipse Glasses.
Astronomy Without Borders has partnered up with Woodland Hills Telescopes to sell AWB-branded eclipse glasses.
Here are the details:
These Eclipse Shades® Safe Solar Glasses are absolutely safe for direct solar viewing of solar eclipses and sunspots. The black polymer lens material is scratch resistant, optical density 5 and CE certified. It filters out 100% of harmful ultra-violet, 100% of harmful infrared, and 99.999% of intense visible light and creates a pleasing orange image of the Sun.
The glasses cost $0.95 each when you order 10-25, with bigger discounts from there – so you need to buy in bulk. Obviously, you’d only order these for your classroom, astronomy club, or eclipse/transit party. And if you do buy, 100% of sale proceeds go to Astronomers Without Borders to support astronomy programs worldwide.
Here’s the May 3, 2012 edition of the Weekly Space Hangout, where we were joined by our usual cast of space journalists, including Alan Boyle, Nicole Gugliucci, Ian O’Neill, Jason Major, Emily Lakdawalla and Fraser Cain. We were then joined by two new people, Amy Shira Teitel from Vintage Space and Sawyer Rosenstein from the Talking Space Podcast.
Want to watch an episode live? We record the Weekly Space Hangout every Thursday at 10:00am PDT, 1:00pm EDT. The live show will appear in Fraser’s Google+ stream, or on our YouTube Channel. You can also watch it live over on Cosmoquest.org.
Mars gets all the attention, but you might be surprised to know how much Venus has been explored. From initial telescope observations and the early flyby missions, to the landers… yes landers and orbiters. We know quite a lot about Venus, but the planet sure didn’t give up its secrets easily.
You can watch us record Astronomy Cast live every Monday at 12:00 pm PDT (3:00 pm EDT, 2000 GMT). Make sure you circle Fraser on Google+ to see it show up in the feed. You can also see it live over on our YouTube channel.
If you’d like to be notified of all our live events, sign up for our notification email at Cosmoquest. You can check out our calendar here.
Whenever we do a Virtual Star Party, it’s hit or miss thanks to weather and technology. But last night, all the pieces came together perfectly. We had Stuart Forman on the West Coast delivering amazing video of the Moon, despite a thickening marine layer. Mike Phillips tested out his brand new color webcam and provided the best view of Saturn we’ve ever had (even after dropping a camera on the pavement in the darkness). Peter Lake remotely controlled his awesome robotic New Mexico telescope safely from his secret lair in Australia. Gary Gonella showcased his amazing telescope, revealing subtle details in the Monkey Head and Crab Nebulae. Chris Ridgway and Mark Behrendt were rained out, but joined anyway and shared some recent photos they’d taken.
We’re always looking for more astronomers to join in and help cover the night sky. If you think you can participate, please drop me an email and let me know.
The Moon is one of the most familiar and beautiful objects in the night sky (and daytime too!). Let’s take a look at some beautiful images of the Moon. Of course, since Universe Today is a space and astronomy website, all of these pictures of the Moon were taken by spacecraft, or people on board spacecraft.
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Here’s one of the most important pics of the Moon ever captured. That’s because you can see the whole of the Earth as well. This picture of the Moon is called Earthrise, and it was taken by NASA’s astronauts on board Apollo 8 just after it completed its lunar insertion orbit.
The Moon at its nearest and furthest points of its orbit. Image credit: NASA
The Moon follows an elliptical orbit as it travels around the Earth. At some points in its orbit, the Moon is closer to the Earth than others. This picture of the Moon from NASA’s Galileo spacecraft shows the difference in sizes that the Moon can get.
The Earth and Moon, seen from the shuttle Discovery. Image credit: NASA
This is a picture of the Moon, but it’s also a picture of the Earth, seen from space as well as the space shuttle Discovery. This image of the Moon was captured during a mission in 1998.
Here’s a side of the Moon that very few people have ever seen with their own eyes. This photo of the Moon shows its far side. The image was taken by NASA’s Galileo spacecraft as it was speeding out on its journey to Jupiter.
Formation of the Moon
And finally, this isn’t a photograph, but it’s an artist’s illustration of what might have happened during the formation of the Moon. In this image of the Moon, a Mars-sized object is crashing into the Earth. After this, the spray of debris from the collision orbited the Earth and eventually collected together to form the Moon.
Moon Landing Photos
Apollo moon landing sites
For all you conspiracy buffs out there, here’s evidence that the Moon landings really happened. Here are some pictures of the lunar surface taken by NASA’s Lunar Reconnaissance Orbiter showing the location of all the lunar landings. The pictures are so high resolution, you can see the shadows of the lander and even the astronaut footprints.
A Scientist on the Moon
This is a portrait of astronaut and scientist Harrison H. Schmitt standing beside the US flag on the Moon. While most astronauts were test pilots, Schmitt was an actual geologist. It was incredibly useful to have a scientist studying the lunar rocks and soil, searching for evidence.
Alan Bean with Lunar Soil
This is astronaut Alan Bean standing on the surface of the Moon. He’s holding a special container that has lunar soil in it. This picture was taken in the vicinity of Sharp Crater.
Footprints on the Moon
Here’s a classic picture of Buzz Aldrin’s footprint on the Moon; he was the second person to set foot on the Moon. Because there’s no weather on the Moon, this footprint should remain here for millions of years.
Aldrin joined Armstrong on the surface
This is a photo of Buzz Aldrin climbing down outside the Apollo 11 capsule, becoming the second person to set foot on the surface of the Moon. This picture was taken by Neil Armstrong, the first person on the Moon.
Full Moon Pictures
Full Moon Photographed by Expedition 10
This is a stunning photo of full moon taken by the astronauts onboard the International Space Station during the Expedition 10 mission. The moon is the only natural satellite of the planet Earth.
Moon Aglow
This breathtaking photo moon and the earth’s atmosphere was taken from the International Space Station by an Expedition 10 crew member in October 2004. Expedition 10 crew members, Leroy Chiao and Salizhan Sharipov relieved the two Expedition 9 crew members, Mike Fincke and Gennady Padalka.
Full Moon Against Earth's Limb
Here’s another amazing picture of the moon in full view. This image was taken by the Expedition 12 crew members onboard the International Space Station on February 12, 2006.
Full Moon with Earth's Horizon and Airglow Visible at Left
This is an Expedition 14 picture of the full moon taken on December 4, 2006. The moon is the brightest object visible in the earth’s sky after the sun.
Earth's Moon
Here’s a nice photo of the earth’s moon generated from the 18 images captured by the Galileo spacecraft on December 7, 1992 on its way to Jupiter. The Moon is the only natural satellite of the earth. The moon’s surface, as seen on the image is composed of many impact craters.
New Moon Pictures
Almost New Moon with Venus. Image credit: Voobie
This is an image of the Moon when it was almost a new moon. The bright star in the picture isn’t a star at all but the planet Venus. This photo was taken by Voobie.
This is an image of a double conjunction, where the Moon was close in the sky to two planets, Jupiter and Venus.
New Moon with airplane. Image credit: Stefan Seip
Amateur astronomer Stefan Seip caught this amazing photograph of a passenger airplane passing in front of an almost perfect New Moon.
New moon with Venus. Image credit: James W. Young
Another great image of a new moon. This time the Moon is only 37 hours old. This picture was taken by James W. Young from the Table Mountain Observatory.
Last week we talked about the orbiter portion of the Viking Missions. But that was only half the adventure. Each Viking spacecraft carried a lander as well, which touched down on the surface of Mars, searching for evidence of past and current life. And what they discovered is still up for debate.
We record Astronomy Cast live every Monday at 12 pm PST / 3 pm EST / 2000 GMT. If you want to join in our recording, just make sure you’ve got Fraser circled on Google+, then the show will show up in your stream. You can also watch us live at Cosmoquest.
[/caption] You can take some meteor showers to the bank, like the Leonids, Perseids and Geminids. Other showers are more spikey; they can underperform one year, with just a few dozen meteors an hour, or boost up to hundreds in an hour – a full on meteor storm! Our next meteor shower, the Lyrids, is one of those examples, especially when the peak night coincides with a new Moon: April 21/22, 2012. Is it going to be amazing this year? There’s only one way to find out – get outside, and look up.
The meteors come from Comet Thatcher (C/1861 G1); the trail of debris left behind as it makes a 415-year highly elliptical journey around the Sun. And each year the Earth passes through this trail, scooping up the the tiny particles of ice and dust and annihilating them in the atmosphere. Thatcher’s loss is our gain.
They’re named for the constellation Lyra, since the meteors appear to emanate from a region just off to the side of the familiar constellation – the bright star Vega is part of Lyra. Don’t just look at that one spot, though, meteors can be seen anywhere in the sky.
Each year the Lyrids start to build around April 16, peaking on April 21/22, and then fade away by April 26. At the peak, the Lyrids can deliver 10-20 meteors per hour. But there can also be spikes of activity, with more than 100 meteors per hour, as the Earth passes through clumps in the dust trail.
It’s almost impossible to know, in advance, if it’s going to be a great year for any specific meteor shower. But this year’s Lyrids Meteor Shower coincides with a new Moon on April 21. Without the glare of a bright Moon, the meteors are easier to spot.
You can see the shower from any spot on Earth, just head outside on the evening of April 21, and give your eyes time to adjust to the dark skies. Get out of the glare of a city if you can, to a dark enough location that you can see the Milky Way once the skies have fully darkened. Here’s a handy map you can use to find dark sky locations in the US.
Of course, meteor showers are best shared with friends. Gather together some fellow astro-enthusiasts, pack some warm clothing, and enjoy the sky show. If you can, try to time your viewing as late as possible, or even in the early morning, when the sky has fully darkened and the stars are really bright.
And be patient. It might take a few hours, but you could be lucky enough to see a Lyrid fireball blaze across the sky, burning a trail into the night sky for a few moments. Just one fireball will make your whole evening worth while.
MESSENGER's first image from Mercury orbit, with the bright Debussy crater visible at upper right. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
[/caption] Quick Mercury Stats Mass: 0.3302 x 1024 kg Volume: 6.083 x 1010 km3 Average radius: 2439.7 km Average diameter: 4879.4 km Density: 5.427 g/cm3 Escape velocity: 4.3 km/s Surface gravity: 3.7 m/s2 Visual magnitude: -0.42 Natural satellites: 0 Rings? – No Semimajor axis: 57,910,000 km Orbit period: 87.969 days Perihelion: 46,000,000 km Aphelion: 69,820,000 km Mean orbital velocity: 47.87 km/s Maximum orbital velocity: 58.98 km/s Minimum orbital velocity: 38.86 km/s Orbit inclination: 7.00° Orbit eccentricity: 0.2056 Sidereal rotation period: 1407.6 hours Length of day: 4222.6 hours Discovery: Known since prehistoric times Minimum distance from Earth: 77,300,000 km Maximum distance from Earth: 221,900,000 km Maximum apparent diameter from Earth: 13 arc seconds Minimum apparent diameter from Earth: 4.5 arc seconds Maximum visual magnitude: -1.9
Size of Mercury
How big is Mercury? Mercury is the smallest planet in the Solar System by surface area, volume, and equatorial diameter. Surprisingly, it is also one of the most dense. It gained its ‘smallest’ title after Pluto was demoted. That is why older material refers to Mercury as the second smallest planet. The aforementioned are the three criteria that we will use to show the size of Mercury in relation to Earth.
Some scientists think that Mercury is actually shrinking. The liquid core of the planet occupies about 42% of the planet’s volume. The spin of the planet allows a small portion of the core to cool. This cooling and shrinking is thought to be evidenced by the fracturing of the planet’s surface.
The surface of Mercury is heavily cratered, much like the Moon, and the continued presence of those craters indicates that the planet has not been geologically active for billions of years. That knowledge is based on partial mapping of the planet(55%). It is unlikely to change even after NASA’s MESSENGER spacecraft maps the entire surface. The planet was most likely bombarded heavily by asteroids and comets during the Late Heavy Bombardment about 3.8 billion years ago. Some regions would have been filled by magma eruptions from within the planet. These created smooth plains similar to those found on the Moon. As the planet cooled and contracted cracks and ridges formed. These features can be seen on top of other features, which is a clear indication that they are more recent. Volcanic eruptions ceased on Mercury about 700-800 million years ago when the planet’s mantle had contracted enough to prevent lava flow. This WAC image showing a never-before-imaged area of Mercury’s surface was taken from an altitude of ~450 km (280 miles) above Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington Diameter of Mercury (and the Radius)
The diameter of Mercury is 4,879.4 km.
Need some way to compare that to something more familiar? The diameter of Mercury is only 38% the Earth’s diameter. In other words, you could put almost 3 Mercurys side to side to match the diameter of Earth.
In fact, there are two moons in the Solar System which actually have a larger diameter than Mercury. The largest moon in the Solar System is Jupiter’s moon Ganymede, with a diameter of 5,268 km and the second largest moon is Saturn’s moon Titan, with a diameter of 5,152 km.
The Earth’s moon is only 3,474 km, so Mercury isn’t much bigger.
If you want to calculate the radius of Mercury, you need to divide the diameter of Mercury in half. While the diameter is 4,879.4 km, the radius of Mercury is only 2,439.7 km.
Diameter of Mercury in kilometers: 4,879.4 km Diameter of Mercury in miles: 3,031.9 miles Radius of Mercury in kilometers: 2,439.7 km Radius of Mercury in miles: 1,516.0 miles
Circumference of Mercury
The circumference of Mercury is 15,329 km. In other words, if Mercury’s equator was perfectly flat, and you could drive around it in your car, your odomotor would add 15,329 km from the trip.
Most planets are oblate spheroids, so their equatorial circumference is larger than their pole to pole. The more rapidly they spin, the more the planet flattens out, so the distance from the center of the planet to its poles is shorter than the distance from the center to the equator. But Mercury rotates so slowly that its circumference is the same no matter where you measure it.
You can calculate the circumference of Mercury all by yourself, using the classic mathematical formulae to get the circumference of a circle.
Circumference = 2 x pi x radius
We know the radius of Mercury is 2,439.7 km. So if you put these numbers in: 2 x 3.1415926 x 2439.7, you get 15,329 km.
Circumference of Mercury in kilometers: 15,329 km Circumference of Mercury in miles: 9,525 miles Crescent Mercury Volume of Mercury
The volume of Mercury is 6.083 x 1010km3. That seems to be a huge number on the face of it, but Mercury is the smallest planet in the Solar System by volume (since the demotion of Pluto). It is even smaller than some of the moons in our Solar System. The Mercurian volume is only 5.4% of Earth’s and the Sun has 240.5 million times the volume of Mercury.
Over 40% of Mercury’s volume is occupied by its core, 42% to be exact. The core is about 3,600 km in diameter. That makes Mercury the second most dense planet amongst our eight. The core is molten and mainly consists of iron. The molten core is able to produce a magnetic field which helps to deflect the solar wind. The magnetic field and slight gravity of the planet allow it to hold onto a tenuous atmosphere.
It is thought that Mercury was at one time a larger planet and; therefore, had a higher volume. There is one theory to explain its current size that many scientists accept on several levels. The theory explains Mercury’s density and the high percentage of core material. The theory states that Mercury originally had a metal-silicate ratio similar to common meteorites, as is typical of rocky matter in our Solar System. At that time, the planet is thought to have had a mass approximately 2.25 times its current mass, but, early in the Solar System’s history, it was struck by a planetesimal that was about 1/6 its mass and several hundred kilometers in diameter. The impact would have stripped away much of the original crust and mantle, leaving the core as a large percentage of the planet and greatly reducing the planet’s volume as well.
Volume of Mercury in cubic kilometers: 6.083 x 1010km3
Mass of Mercury
The mass of Mercury is only 5.5% of the Earth’s; the actual value is 3.30 x 1023 kg. Since Mercury is the smallest planet in the Solar System, you would expect this relatively small mass. On the other hand, Mercury is the second most dense planet in our Solar System (after Earth). Given its size, the density comes largely from its core, estimated at almost half the planet’s volume.
The planet’s mass is comprised of materials that are 70% metallic and 30% silicate. There are several theories to explain why the planet is so dense and the abundance of metallic material. The most widely held theory holds that the high core percentage is the result of an impact. In this theory the planet originally had a metal-silicate ratio similar to the chondrite meteorites common in the Universe and around 2.25 times its current mass. Early in the history of our Solar System, Mercury was struck by a planetesimal sized impactor that was about 1/6 of its hypothesized mass and hundreds of km in diameter. An impact of that magnitude would strip away much of the crust and mantle, leaving behind a large core. Scientists believe that a similar incident created our moon. An additional theory says that the planet formed before the Sun’s energy had stabilized. The planet would have had much more mass in this theory as well, but the temperatures created by the protosun would have been as high as 10,000 K and the majority of the surface rock could have been vaporized. The rock vapor could have then been carried away by the solar wind.
Mass of Mercury in kg: 0.3302 x 1024 kg Mass of Mercury in pounds: 7.2796639 x 1023 pounds Mass of Mercury in tonnes: 3.30200 x 1020 tonnes Mass of Mercury in tons: 3.63983195 x 1020 Artist's concept of MESSENGER in orbit around Mercury. Courtesy of NASA Gravity on Mercury
Gravity on Mercury is 38% of the gravity here on Earth. A man weighing 980 Newtons on Earth (about 220 pounds), would only weigh about 372 Newtons (83.6 pounds) landing on the planet’s surface. Mercury is only slightly bigger than our moon, so you might expect its gravity to be similar to the Moon’s at 16% of Earth’s. The big difference Mercury’s higher density – it’s the second densest planet in the Solar System. In fact, if Mercury were the same size as Earth, it would be even more dense than our own planet.
It’s important to clarify the difference between mass and weight. Mass measures how much stuff something contains. So if you have 100 kg of mass on Earth, you will have the same amount on Mars, or intergalactic space. Weight, however, is the force of gravity you feel. While bathroom scales measure pounds or kilograms, they should really be measuring newtons, which is a measure of weight.
Take your current weight in either pounds or kilograms and then multiply it by 0.38 with a calculator. For example, if you weigh 150 pounds, you’d weigh 57 pounds on Mercury. If you weigh 68 kilograms on the bathroom scale, your weight on Mercury would be 25.8 kg.
You can also turn this number around to figure out how much stronger you would be. For example, how high you could jump, or how much weight you could lift. The current world record for the high jump is 2.43 meters. Divide 2.43 by 0.38, and you get the world’s high jump record if it were done on Mercury. In this case, it would be 6.4 meters.
In order to escape the gravity of Mercury, you would need to be traveling 4.3 kilometers/second, or about 15,480 kilometers per hour. Compare this to Earth, where the escape velocity of our planet is 11.2 kilometers per second. If you compare the ratio between our two planets, you get 38%.
Surface gravity of Mercury: 3.7 m/s2 Escape velocity of Mercury: 4.3 kilometers/second
Density of Mercury
The density of Mercury is the second highest in the Solar System. Earth is the only planet that is more dense. It is 5.427 g/cm3 compared to Earth’s 5.515 g/cm3. If gravitational compression were to be removed from the equation, Mercury would be more dense. The high density of the planet is attributed to its large percentage of core. The core constitutes 42% of Mercury’s overall volume.
Mercury is a terrestrial planet like Earth, one of only four in our Solar System. Mercury is about 70% metallic material and 30% silicates. Add the density of Mercury and scientists can infer details of its internal structure. While the Earth’s high density mainly results from gravitational compression at the core, Mercury is much smaller and is not so tightly compressed internally. These facts have allowed NASA scientists and others to surmise that its core must be large and contain overwhelming amounts of iron. Planetary geologists estimate that the planet’s molten core accounts for about 42% of its volume. On Earth that percentage is 17. Interior of Mercury
That leaves a silicate mantle that is only 500–700 km thick. Data from Mariner 10 led scientists to believe that the crust is even thinner, at a mere 100–300 km. This surrounds a core that has a higher iron content than any other planet in the Solar System. So, what caused this disproportionate amount of core material? Most scientists accept the theory that Mercury had a metal-silicate ratio similar to common chondrite meteorites several billion years ago. They also believe that it had a mass of about 2.25 times its current; however, Mercury may have been impacted by a planetesimal 1/6 that mass and hundreds of km in diameter. The impact would have stripped away much of the original crust and mantle, leaving the core as a major percentage of the planet.
While scientists have a few facts about the density of Mercury, there is still more to be discovered. Mariner 10 send back a great deal information, but was only able to study about 44% of the planet’s surface. The MESSENGER mission is filling in some of the blanks as you are reading this article and the BepiColumbo mission will go even farther in extending our knowledge of the planet. Soon, there mat be more than theories to explain the high density of the planet.
Density of Mercury in grams per cubic centimeter: 5.427 g/cm3
Axis of Mercury
Like all of the planets in the Solar System, the axis of Mercury is tilted away from the plane of the ecliptic. In this case, Mercury’s axial tilt is 2.11 degrees.
What exactly is a planet’s axial tilt? First imagine that the Sun is a ball in the middle of a flat disk, like a record or a CD. The planets orbit around the Sun within this disk (more or less). That disk is known as the plane of the ecliptic. Each planet is also spinning on its axis as it’s orbiting around the Sun. If planet was spinning perfectly straight up and down, so that a line running through the north and south poles of the planet was perfectly parallel with the Sun’s poles, the planet would have a 0-degree axial tilt. Of course, none of the planets are like this.
So if you drew a line between Mercury’s north and south poles and compared it to an imaginary line if the Mercury had no axial tilt at all, that angle would measure 2.11 degrees. You might be surprised to know that this Mercury tilt is actually the smallest of all the planets in the Solar System. For example, the Earth’s tilt is 23.4 degrees. And Uranus is actually flipped completely over on its axis, and rotates with an axial tilt of 97.8 degrees.
Here on Earth, the axial tilt of our planet causes the seasons. When it’s summer in the northern hemisphere, the Earth’s north pole is angled towards the Sun. and then in the winter, the north pole is angled away. We get more sunlight in the summer so it’s warmer, and less in the winter.
Mercury barely experiences any seasons at all. This is because it has almost no axial tilt. Of course, it also doesn’t have much of an atmosphere to hold the Sun’s heat. Whichever side is facing the Sun is heated to 700 degrees Kelvin, and the side facing away drops to less than 100 Kelvin.
The Cygnus Loop in Ultraviolet. Captured by Galex. Image credit: NASA
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You’re looking at an insanely beautiful image of the Cygnus Loop nebula captured by NASA’s Galaxy Evolution Explorer (GALEX) mission. Furthermore, this isn’t viewed in plain old visible light, this is high-energy ultraviolet light, revealing regions of hot gas remaining after a supernova detonated here 5,000 to 8,000 years ago.
In fact, the original supernova would have been bright enough to be visible with the unaided eye.
The Cygnus Loop Nebula, also known as W78 or Sharpless 103, is a huge emission nebula measuring more than 3° across. There are many smaller features inside the complex, like the Veil Nebula, the Western Veil (the Witch’s Broom), Eastern Veil and Pickering’s Triangle. Many will be familiar to astronomers and astrophotographers as they’re large and faint, and can only really be revealed with long exposure images in various narrowband filters.
Astronomers originally believed it was located about 2,500 light-years away, but according to newer research with the Hubble Space Telescope, they’ve pegged its distance at only 1,470 light-years away; and it now stretches across a distance of 90 light-years.
This extremely close distance is important. There are many supernova remnants like this, scattered across our galaxy, but none are so close, taking up such a vast region of our skies.
This view was captured by NASA’s GALEX mission, which launched in April 2003. Its main purpose was to image hundreds of thousands of galaxies, charting their rates of star formation – the science is best gathered in ultraviolet. Unfortunately, NASA cut off financial support for the mission back in February, 2011, but control might be transferred to the California Institute of Technology.
Periodic Bedrock Ridges on Mars. Image credit: University of Washington
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Geologists are often surprised to find features on Earth replicated on other worlds; ancient riverbeds on Mars, lakes on Titan, and volcanic eruptions on Io. But researchers from the University of Washington have identified a geologic feature that exists on Mars…
But not on Earth.
These structures are known as periodic bedrock ridges. They look like sand dunes on the surface of Mars, but instead of sand piled high by strong winds, it appears that the wind has carved dune-like ridges right into the Martian bedrock.
“These bedforms look for all the world like sand dunes but they are carved into hard rock by wind,” said David Montgomery, a UW professor of Earth and space sciences. It is something there are not many analogs for on Earth.”
A yardang in Texas. Image credit: USDA
What could create such a unique feature? According to Prof. Montgomery, the ridges are probably a softer form of bedrock, which is easier for the Martian wind to erode it away. One similar feature on Earth is known as a “yardang”, but these are teardrop-shaped features parallel to the direction of the wind.
But on Mars, these periodic bedrock ridges are perpendicular to the flow of the prevailing wind, just how sand dunes form on Earth (and Mars).
The additional ingredient in the weather on Mars is probably some kind of deflection. The high speed surface winds are deflected up into the air by a land formation, and then they come down to the surface and create these periodic ridges. The length of the gap in the ridges depends on the strength of the wind, size of the deflection and the density of the atmosphere.
Apart from the fact that this is just really cool, there’s a scientific benefit too. This wind will expose layers of rock, created eons ago. A rover could travel across these ridges, sampling very different ages of Martian geology in a local area.
It would be an all-you-can-eat Martian geology buffet.
Original Source: University of Washington News Release
