At the recent ceremony for the Hyperloop Pod Competition, Musk announced that his concept for a high-speed train might work better on Mars. Credit: HTT
Elon Musk has always been up-front about his desire to see humans settle on the Red Planet. In the past few years, he has said that one of his main reasons for establishing SpaceX was to see humanity colonize Mars. He has also stated that he believes that using Mars as a “backup location” for humanity might be necessary for our survival, and even suggested we use nukes to terraform it.
And in his latest speech extolling the virtues of colonizing Mars, Musk listed another reason. The Hyperloop – his concept for a high-speed train that relies steel tubes, aluminum cars and maglev technology to go really fast – might actually work better in a Martian environment. The announcement came as part of the award ceremony for the Hyperloop Pod Competition, which saw 100 university teams compete to create a design for a Hyperloop podcar.
It was the first time that Musk has addressed the issue of transportation on Mars. In the past, he has spoken about establishing a colony with 80,000 people, and has also discussed his plans to build a Mars Colonial Transporter to transport 100 metric tons (220,462 lbs) of cargo or 100 people to the surface of Mars at a time (for a fee of $50,000 apiece). He has also discussed communications, saying that he would like to bring the internet to Mars once a colony was established.
Artist’s concept of what a Hyperloop pod car’s interior might look like. Credit: Tesla
But in addressing transportation, Musk was able to incorporate another important concept that he has come up with, and which is also currently in development. Here on Earth, the Hyperloop would rely on low-pressure steel tubes and a series of aluminum pod cars to whisk passengers between major cities at speeds of up to 1280 km/h (800 mph). But on Mars, according to Musk, you wouldn’t even need tubes.
As Musk said during the course of the ceremony: “On Mars you basically just need a track. You might be able to just have a road, honestly. [It would] go pretty fast… It would obviously have to be electric because there’s no oxygen. You have to have really fast electric cars or trains or things.”
Essentially, Musk was referring to the fact that since Mars has only 1% the air pressure of Earth, air resistance would not be a factor. Whereas his high-speed train concept requires tubes with very low air pressure to reach the speed of sound here on Earth, on Mars they could reach those speeds out in the open. One might say, it actually makes more sense to build this train on Mars rather than on Earth!
The Hyperloop Pod Competition, which was hosted by SpaceX, took place between Jan 27th and 29th. The winning entry came from MIT, who’s design was selected from 100 different entries. Their pod car, which is roughly 2.5 meters long and 1 meter wide (8.2 by 3.2 feet), would weight 250 kg (551 lbs) and be able to achieve an estimated cruise speed of 110 m/s (396 km/h; 246 mph). While this is slightly less than a third of the speed called for in Musk’s original proposal, this figure representing cruising speed (not maximum speed), and is certainly a step in that direction.
Team MIT’s Hyperloop pod car design. Credit: MIT/Twitter
And while Musk’s original idea proposed that the pod be lifted off the ground using air bearings, the MIT team’s design called for the use of electrodynamic suspension to keep itself off the ground. The reason for this, they claimed, is because it is “massively simpler and more scalable.” In addition, compared to the other designs’ levitation systems, theirs had one of the lowest drag coefficients.
The team – which consists of 25 students with backgrounds in aeronautics, mechanical engineering, electrical engineering, and business management – will spend the next five months building and testing their pod. The final prototype will participate in a trial run this June, where it will run on the one-mile Hyperloop Test Track at SpaceX’s headquarters in California.
Since he first unveiled it back in 2013, Musk’s Hyperloop concept has been the subject of considerable interest and skepticism. However, in the past few years, two companies – Hyperloop Transportation Technologies (HTT) and Hyperloop Technologies – have emerged with the intention of seeing the concept through to fruition. Both of these companies have secured lucrative partnerships since their inception, and are even breaking ground on their own test tracks in California and Nevada.
And with a design for a podcar now secured, and tests schedules to take place this summer, the dream of a “fifth mode of transportation” is one step closer to becoming a reality! The only question is, which will come first – Hyperloops connecting major cities here on Earth, or running passengers and freight between domed settlements on Mars?
Only time will tell! And be sure to check out Team MIT’s video:
"Cauliflower" shaped silica-rich rocks photographed by the Spirit Rover near the Home Plate rock formation in Gusev Crater in 2008. Could microbes have built their nodular shapes? Credit: NASA/JPL-Caltech
“Cauliflower” shaped silica-rich rocks photographed by the Spirit Rover near the Home Plate rock formation in Gusev Crater in 2008. Credit: NASA/JPL-Caltech
Evidence of water and a warmer, wetter climate abound on Mars, but did life ever put its stamp on the Red Planet? Rocks may hold the secret. Knobby protuberances of rock discovered by the Spirit Rover in 2008 near the rock outcrop Home Plate in Gusev Crater caught the attention of scientists back on Earth. They look like cauliflower or coral, but were these strange Martian rocks sculpted by microbes, wind or some other process?
Close-up of the lobed silica rocks on Mars photographed by the Spirit Rover’s microscopic imager on Sol 1157. It’s not known where wind (or other non-biological process) or micro-life had a hand in creating these shapes. Credit: NASA/ JPL-Caltech
When analyzed by Spirit’s mini-TES (Mini-Thermal Emission Spectrometer), they proved to be made of nearly pure silica (SiO2), a mineral that forms in hot, volcanic environments. Rainwater and snow seep into cracks in the ground and come in contact with rocks heated by magma from below. Heated to hundreds of degrees, the water becomes buoyant and rises back toward the surface, dissolving silica and other minerals along the way before depositing them around a vent or fumarole. Here on Earth, silica precipitated from water leaves a pale border around many Yellowstone National Park’s hot springs.
The Grand Prismatic Spring at Yellowstone National Park. Could it be an analog to similar springs, hydrothermal vents and geysers that may once have existed in Gusev Crater on Mars? Credit: Jim Peaco, National Park Service
Both at Yellowstone, the Taupo Volcanic Zonein New Zealand and in Iceland, heat-loving bacteria are intimately involved in creating curious bulbous and branching shapes in silica formations that strongly resemble the Martian cauliflower rocks. New research presented at the American Geophysical Union meeting last month by planetary geologist Steven Ruff and geology professor Jack Farmer, both of Arizona State University, explores the possibility that microbes might have been involved in fashioning the Martian rocks, too.
A sizzling visit to El Tatio’s geysers
The researchers ventured to the remote geyser fields of El Tatio in the Chilean Atacama Desert to study an environment that may have mimicked Gusev Crater billions of years ago when it bubbled with hydrothermal activity. One of the driest places on Earth, the Atacama’s average elevation is 13,000 feet (4 km), exposing it to considerably more UV light from the sun and extreme temperatures ranging from -13°F to 113°F (-10° to 45°C). Outside of parts of Antarctica, it’s about as close to Mars as you’ll find on Earth.
Ruff and Farmer studied silica deposits around hot springs and geysers in El Tatio and discovered forms they call “micro-digitate silica structures” similar in appearance and composition to those on Mars (Here’s a photo). The infrared spectra of the two were also a good match. They’re still analyzing the samples to determine if heat-loving microbes may have played a role in their formation, but hypothesize that the features are “micro-stromatolites” much like those found at Yellowstone and Taupo.
A stromatolite from Wyoming made of many layers of bacteria-cemented mineral grains. Credit: Bob King
Stromatolites form when a sticky film of bacteria traps and cements mineral grains to create a thin layer. Other layers form atop that one until a laminar mound or column results. The most ancient stromatolites on Earth may be about 3.5 billion years old. If Ruff finds evidence of biology in the El Tatio formations in the punishing Atacama Desert environment, it puts us one step closer to considering the possibility that ancient bacteria may have been at work on Mars.
Scientists have found evidence that Home Plate at Gusev crater on Mars is composed of debris deposited from a hydrovolcanic explosion. The finding suggests that water may have been involved in driving an eruption that formed the deposits found on Home Plate. Spirit found the silica-rich rocks at lower right near Tyrone in 2008. Credit: NASA/JPL-Caltech
Silica forms may originate with biology or from non-biological processes like wind, water and other environmental factors. Short of going there and collecting samples, there’s no way to be certain if the cauliflower rocks are imprinted with the signature of past Martian life. But at least we know of a promising place to look during a future sample return mission to the Red Planet. Indeed, according to Ruff, the Columbia Hills inside Gusev Crater he short list of potential sites for the 2020 Mars rover.
More resources:
Steve Ruff paper comparing El Tatio with an early hot springs environment in Gusev Crater
Here on Earth, we to end to not give our measurements of time much thought. Unless we’re griping about Time Zones, enjoying the extra day of a Leap Year, or contemplating the rationality of Daylight Savings Time, we tend to take it all for granted. But when you consider the fact that increments like a year are entirely relative, dependent on a specific space and place, you begin to see how time really works.
Here on Earth, we consider a year to be 365 days. Unless of course it’s a Leap Year, which takes place every four years (in which it is 366). But the actual definition of a year is the time it takes our planet to complete a single orbit around the Sun. So if you were to put yourself in another frame of reference – say, another planet – a year would work out to something else. Let’s see just how long a year is on the other planets, shall we?
Composite hazcam camera image (left) shows the robotic arm in motion as NASA’s Mars Exploration Rover Opportunity places the tool turret on the target named “Private John Potts” on Sol 4234 to brush away obscuring dust. Rover is actively working on the southern side of “Marathon Valley” which slices through western rim of Endeavour Crater. On Sol 4259 (Jan. 16, 2016), Opportunity completed grinds with the Rock Abrasion Tool (RAT) to exposure rock interior for elemental analysis, as seen in mosaic (right) of four up close images taken by Microscopic Imager (MI). Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
Composite hazcam camera image (left) shows the robotic arm in motion as NASA’s Mars Exploration Rover Opportunity places the tool turret on the target named “Private John Potts” on Sol 4234 to brush away obscuring dust. Rover is actively working on the southern side of “Marathon Valley” which slices through western rim of Endeavour Crater. On Sol 4259 (Jan. 16, 2016), Opportunity completed grinds with the Rock Abrasion Tool (RAT) to exposure rock interior for elemental analysis, as seen in mosaic (right) of four up close images taken by Microscopic Imager (MI). Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
NASA’s world famous Mars Exploration RoverOpportunity continues blazing a daily trail of unprecedented science first’s, still swinging her robotic arm robustly into action at a Martian “Mining Zone” on the 12th anniversary of her hair-raising Red Planet touchdown this week, a top rover scientist told Universe Today.
Curiosity rover 'selfie' at the Bagnold Dunes on Mars. The mosaic includes 57 images taken on Sol 1228 (January 19, 2016). Credit: NASA/JPL-Caltech/MSSS/Andrew Bodrov.
While some of us might only be dreaming of sticking our toes in the sand right about now, the Curiosity rover is actually doing so. But it’s no vacation for the rover, as she makes her way through some very unusual and striking sand dunes on Mars. The Bagnold Dune Field lies along the northwestern flank of Mt. Sharp — Curiosity’s main target for its mission — and this is the first time ever we’ve had the opportunity to do close-up studies of active sand dunes anywhere besides Earth.
Thanks to Andrew Bodrov for sharing his compilation of this 57-image mosaic ‘selfie,’ and you can play around with an interactive version below to see some great views of the dunes. The images were taken by the rover’s Mars Hand Lens Imager (MAHLI) on Sol 1228 (January 19, 2016).
Welding together of Orion EM-1 pressure vessel was completed on Jan. 13, 2016 at NASA’s Michoud Assembly Facility in New Orleans. The pressure vessel is the primary structure of the Orion spacecraft destined for human missions to deep space and Mars. Credits: NASA
Welding together of Orion EM-1 pressure vessel was completed on Jan. 13, 2016 at NASA’s Michoud Assembly Facility in New Orleans. The pressure vessel is the primary structure of the Orion spacecraft destined for human missions to deep space and Mars. Credits: NASA
In a major step towards flight, engineers at NASA’s Michoud Assembly Facility in New Orleans have finished welding together the pressure vessel for the first Lunar Orion crew module that will blastoff in 2018 atop the agency’s Space Launch System (SLS) rocket.
Planets and other objects in our Solar System. Credit: NASA.
Here on Earth, we tend to take time for granted, never suspected that the increments with which we measure it are actually quite relative. The ways in which we measure our days and years, for example, are actually the result of our planet’s distance from the Sun, the time it takes to orbit, and the time it takes to rotate on its axis. The same is true for the other planets in our Solar System.
While we Earthlings count on a day being about 24 hours from sunup to sunup, the length of a single day on another planet is quite different. In some cases, they are very short, while in others, they can last longer than years – sometimes considerably! Let’s go over how time works on other planets and see just how long their days can be, shall we?
A Day On Mercury:
Mercury is the closest planet to our Sun, ranging from 46,001,200 km at perihelion (closest to the Sun) to 69,816,900 km at aphelion (farthest). Since it takes 58.646 Earth days for Mercury to rotate once on its axis – aka. its sidereal rotation period – this means that it takes just over 58 Earth days for Mercury to experience a single day.
However, this is not to say that Mercury experiences two sunrises in just over 58 days. Due to its proximity to the Sun and rapid speed with which it circles it, it takes the equivalent of 175.97 Earth days for the Sun to reappear in the same place in the sky. Hence, while the planet rotates once every 58 Earth days, it is roughly 176 days from one sunrise to the next on Mercury.
Images of Mercury’s northern polar region, provided by MESSENGER. Credit: NASA/JPL
What’s more, it only takes Mercury 87.969 Earth days to complete a single orbit of the Sun (aka. its orbital period). This means a year on Mercury is the equivalent of about 88 Earth days, which in turn means that a single Mercurian (or Hermian) year lasts just half as long as a Mercurian day.
What’s more, Mercury’s northern polar regions are constantly in the shade. This is due to it’s axis being tilted at a mere 0.034° (compared to Earth’s 23.4°), which means that it does not experience extreme seasonal variations where days and nights can last for months depending on the season. On the poles of Mercury, it is always dark and shady. So you could say the poles are in a constant state of twilight.
A Day On Venus:
Also known as “Earth’s Twin”, Venus is the second closest planet to our Sun – ranging from 107,477,000 km at perihelion to 108,939,000 km at aphelion. Unfortunately, Venus is also the slowest moving planet, a fact which is made evident by looking at its poles. Whereas every other planet in the Solar System has experienced flattening at their poles due to the speed of their spin, Venus has experienced no such flattening.
Venus has a rotational velocity of just 6.5 km/h (4.0 mph) – compared to Earth’s rational velocity of 1,670 km/h (1,040 mph) – which leads to a sidereal rotation period of 243.025 days. Technically, it is -243.025 days, since Venus’ rotation is retrograde. This means that Venus rotates in the direction opposite to its orbital path around the Sun.
The planet Venus, as imagined by the Magellan 10 mission. Credit: NASA/JPL
So if you were above Venus’ north pole and watched it circle around the Sun, you would see it is moving clockwise, whereas its rotation is counter-clockwise. Nevertheless, this still means that Venus takes over 243 Earth days to rotate once on its axis. However, much like Mercury, Venus’ orbital speed and slow rotation means that a single solar day – the time it takes the Sun to return to the same place in the sky – lasts about 117 days.
So while a single Venusian (or Cytherean) year works out to 224.701 Earth days, it experiences less than two full sunrises and sunsets in that time. In fact, a single Venusian/Cytherean year lasts as long as 1.92 Venusian/Cytherean days. Good thing Venus has other things in common With Earth, because it is sure isn’t its diurnal cycle!
A Day On Earth:
When we think of a day on Earth, we tend to think of it as a simple 24 hour interval. In truth, it takes the Earth exactly 23 hours 56 minutes and 4.1 seconds to rotate once on its axis. Meanwhile, on average, a solar day on Earth is 24 hours long, which means it takes that amount of time for the Sun to appear in the same place in the sky. Between these two values, we say a single day and night cycle lasts an even 24.
At the same time, there are variations in the length of a single day on the planet based on seasonal cycles. Due to Earth’s axial tilt, the amount of sunlight experienced in certain hemispheres will vary. The most extreme case of this occurs at the poles, where day and night can last for days or months depending on the season.
At the North and South Poles during the winter, a single night can last up to six months, which is known as a “polar night”. During the summer, the poles will experience what is called a “midnight sun”, where a day lasts a full 24 hours. So really, days are not as simple as we like to imagine. But compared to the other planets in the Solar System, time management is still easier here on Earth.
A Day On Mars:
In many respects, Mars can also be called “Earth’s Twin”. In addition to having polar ice caps, seasonal variations , and water (albeit frozen) on its surface, a day on Mars is pretty close to what a day on Earth is. Essentially, Mars takes 24 hours 37 minutes and 22 seconds to complete a single rotation on its axis. This means that a day on Mars is equivalent to 1.025957 days.
The seasonal cycles on Mars, which are due to it having an axial tilt similar to Earth’s (25.19° compared to Earth’s 23.4°), are more similar to those we experience on Earth than on any other planet. As a result, Martian days experience similar variations, with the Sun rising sooner and setting later in the summer and then experiencing the reverse in the winter.
However, seasonal variations last twice as long on Mars, thanks to Mars’ being at a greater distance from the Sun. This leads to the Martian year being about two Earth years long – 686.971 Earth days to be exact, which works out to 668.5991 Martian days (or Sols). As a result, longer days and longer nights can be expected last much longer on the Red Planet. Something for future colonists to consider!
Sunrise at Gale Crater on Mars. Gale is at center top with the mound in the middle, called Mt. Sharp (Aeolis Mons.)
A Day On Jupiter:
Given the fact that it is the largest planet in the Solar System, one would expect that a day on Jupiter would last a long time. But as it turns out, a Jovian day is officially only 9 hours, 55 minutes and 30 seconds long, which means a single day is just over a third the length of an Earth day. This is due to the gas giant having a very rapid rotational speed, which is 12.6 km/s (45,300 km/h, or 28148.115 mph) at the equator. This rapid rotational speed is also one of the reasons the planet has such violent storms.
Note the use of the word officially. Since Jupiter is not a solid body, its upper atmosphere undergoes a different rate of rotation compared to its equator. Basically, the rotation of Jupiter’s polar atmosphere is about 5 minutes longer than that of the equatorial atmosphere. Because of this, astronomers use three systems as frames of reference.
System I applies from the latitudes 10° N to 10° S, where its rotational period is the planet’s shortest, at 9 hours, 50 minutes, and 30 seconds. System II applies at all latitudes north and south of these; its period is 9 hours, 55 minutes, and 40.6 seconds. System III corresponds to the rotation of the planet’s magnetosphere, and it’s period is used by the IAU and IAG to define Jupiter’s official rotation (i.e. 9 hours 44 minutes and 30 seconds)
Jupiter and Io capturing the Sun. Image Credit: NASA/JPL
So if you could, theoretically, stand on the cloud tops of Jupiter (or possibly on a floating platform in geosynchronous orbit), you would witness the sun rising an setting in the space of less than 10 hours from any latitude. And in the space of a single Jovian year, the sun would rise and set a total of about 10,476 times.
A Day On Saturn:
Saturn’s situation is very similar to that of Jupiter’s. Despite its massive size, the planet has an estimated rotational velocity of 9.87 km/s (35,500 km/h, or 22058.677 mph). As such Saturn takes about 10 hours and 33 minutes to complete a single sidereal rotation, making a single day on Saturn less than half of what it is here on Earth. Here too, this rapid movement of the atmosphere leads to some super storms, not to mention the hexagonal pattern around the planet’s north pole and a vortex storm around its south pole.
And, also like Jupiter, Saturn takes its time orbiting the Sun. With an orbital period that is the equivalent of 10,759.22 Earth days (or 29.4571 Earth years), a single Saturnian (or Cronian) year lasts roughly 24,491 Saturnian days. However, like Jupiter, Saturn’s atmosphere rotates at different speed depending on latitude, which requires that astronomers use three systems with different frames of reference.
System I encompasses the Equatorial Zone, the South Equatorial Belt and the North Equatorial Belt, and has a period of 10 hours and 14 minutes. System II covers all other Saturnian latitudes, excluding the north and south poles, and have been assigned a rotation period of 10 hr 38 min 25.4 sec. System III uses radio emissions to measure Saturn’s internal rotation rate, which yielded a rotation period of 10 hr 39 min 22.4 sec.
This portrait looking down on Saturn and its rings was created from images obtained by NASA’s Cassini spacecraft on Oct. 10, 2013. Credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic
Using these various systems, scientists have obtained different data from Saturn over the years. For instance, data obtained during the 1980’s by the Voyager 1 and 2 missions indicated that a day on Saturn was 10 hours 39 minutes and 24 seconds long. In 2004, data provided by the Cassini-Huygens space probe measured the planet’s gravitational field, which yielded an estimate of 10 hours, 45 minutes, and 45 seconds (± 36 sec).
In 2007, this was revised by researches at the Department of Earth, Planetary, and Space Sciences, UCLA, which resulted in the current estimate of 10 hours and 33 minutes. Much like with Jupiter, the problem of obtaining accurate measurements arises from the fact that, as a gas giant, parts of Saturn rotate faster than others.
A Day On Uranus:
When we come to Uranus, the question of how long a day is becomes a bit complicated. One the one hand, the planet has a sidereal rotation period of 17 hours 14 minutes and 24 seconds, which is the equivalent of 0.71833 Earth days. So you could say a day on Uranus lasts almost as long as a day on Earth. It would be true, were it not for the extreme axial tilt this gas/ice giant has going on.
With an axial tilt of 97.77°, Uranus essentially orbits the Sun on its side. This means that either its north or south pole is pointed almost directly at the Sun at different times in its orbital period. When one pole is going through “summer” on Uranus, it will experience 42 years of continuous sunlight. When that same pole is pointed away from the Sun (i.e. a Uranian “winter”), it will experience 42 years of continuous darkness.
Uranus as seen by NASA’s Voyager 2. Credit: NASA/JPL
Hence, you might say that a single day – from one sunrise to the next – lasts a full 84 years on Uranus! In other words, a single Uranian day is the same amount of time as a single Uranian year (84.0205 Earth years).
In addition, as with the other gas/ice giants, Uranus rotates faster at certain latitudes. Ergo, while the planet’s rotation is 17 hours and 14.5 minutes at the equator, at about 60° south, visible features of the atmosphere move much faster, making a full rotation in as little as 14 hours.
A Day On Neptune:
Last, but not least, we have Neptune. Here too, measuring a single day is somewhat complicated. For instance, Neptune’s sidereal rotation period is roughly 16 hours, 6 minutes and 36 seconds (the equivalent of 0.6713 Earth days). But due to it being a gas/ice giant, the poles of the planet rotate faster than the equator.
Whereas the planet’s magnetic field has a rotational speed of 16.1 hours, the wide equatorial zone rotates with a period of about 18 hour. Meanwhile, the polar regions rotate the fastest, at a period of 12 hours. This differential rotation is the most pronounced of any planet in the Solar System, and it results in strong latitudinal wind shear.
Reconstruction of Voyager 2 images showing the Great Black spot (top left), Scooter (middle), and the Small Black Spot (lower right). Credit: NASA/JPL
In addition, the planet’s axial tilt of 28.32° results in seasonal variations that are similar to those on Earth and Mars. The long orbital period of Neptune means that the seasons last for forty Earth years. But because its axial tilt is comparable to Earth’s, the variation in the length of its day over the course of its long year is not any more extreme.
As you can see from this little rundown of the different planets in our Solar System, what constitutes a day depends entirely on your frame of reference. In addition to it varying depending on the planet in question, you also have to take into account seasonal cycles and where on the planet the measurements are being taken from.
As Einstein summarized, time is relative to the observer. Based on your inertial reference frame, its passage will differ. And when you are standing on a planet other than Earth, your concept of day and night, which is set to Earth time (and a specific time zone) is likely to get pretty confused!
Photo of first ever blooming space Zinnia flower grown onboard the International Space Station's Veggie facility moved to catch the sun’s rays through the windows of the Cupola backdropped by Earth. Credit: NASA/Scott Kelly/@StationCDRKelly
Furthermore its contributing invaluable experience to scientists and astronauts on learning how to grow plants and food in microgravity during future deep space human expeditions planned for NASA’s “Journey to Mars” initiative.
