Mystery Mars Cloud: An Auroral Umbrella?

The strange cloud-like protursion above Mars' limb (around the 1 o'clock point). Credit: Wayne Jaeschke.

The strange cloud-like protursion above Mars' limb (around the 1 o'clock point). Credit: Wayne Jaeschke.

Last week, amateur astronomer Wayne Jaeschke noticed something peculiar in his observations of Mars — there appeared to be a cloud-like structure hanging above the limb of the planet.

Many theories have been put forward as to what the phenomenon could be — high altitude cloud? Dust storm? An asteroid impact plume?! — but it’s all conjecture until we can get follow-up observations. It is hoped that NASA’s Mars Odyssey satellite might be able to slew around and get a close-up view. However, it appears to be a transient event that is decreasing in size, so follow-up observations may not be possible.

For the moment, it’s looking very likely that it is some kind of short-lived atmospheric feature, and if I had to put money on it, I’d probably edge more toward the mundane — like a high-altitude cloud formation.

But there is one other possibility that immediately came to mind when I saw Jaeschke’s photograph: Could it be the effect of a magnetic umbrella?

Despite the lack of a global magnetic field like Earth’s magnetosphere, Mars does have small pockets of magnetism over its surface. When solar wind particles collide with the Earth’s magnetosphere, highly energetic particles are channeled to the poles and impact the high altitude atmosphere — aurorae are the result. On Mars, however, it’s different. Though the planet may not experience the intense “auroral oval” like its terrestrial counterpart, when the conditions are right, solar particles my hit these small pockets of magnetism. The result? Auroral umbrellas.

The physics is fairly straight forward — the discreet magnetic pockets act as bubbles, directing the charged solar particles around them in an umbrella fashion. There is limited observational evidence for these space weather features, but they should be possible.

As the sun is going through a period of unrest, amplifying the ferocity of solar storms, popping off coronal mass ejections (CMEs) and solar flares, could the cloud-like feature seen in Jaeschke’s photograph be a bright auroral umbrella? I’m additionally curious as a magnetic feature like this would be rooted in the planet’s crust and would move with the rotation of the planet. It would also be a transient event — much like an atmospheric phenomenon.

The physics may sound plausible, but it would be interesting to see what amateur astronomers think. Could such a feature appear in Mars observations?

For more information, see Jaeschke’s ExoSky website.

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The Funky Craters of Mars

A menagerie of strange divots (NASA/HiRISE/Univ. of Arizona)

A menagerie of strange divots (NASA/HiRISE/Univ. of Arizona)

As 2011 draws to a close, it’s time to reflect on my absenteeism from Astroengine. But it’s not my fault, I’ve been typing like a madman for these guys.

But that’s enough excuses, 2012 promises to be a huge year for space, and if I get my time management skills back up to scratch, there will be a whole lot more of the blogging thing going on over here too. So to kick things off I thought I’d share a cool slide show I’ve been working on for Discovery News with Ari Espinoza of the High-Resolution Imaging Science Experiment (HiRISE) — the awesome camera currently orbiting Mars aboard NASA’s Mars Reconnaissance Orbiter (MRO).

With the help of Ari, we managed to collect some weird-looking Mars craters (for the hell of it) and create a slide show with some of the strangest. Below are a few of my favorites, but be sure to check out the full slide show for more oddities!

Exoplanet Count Tops 700

An artist's impression of a lone exoplanet transiting its parent star. There are now 700 confirmed alien worlds orbiting other stars (ESO)

An artist's impression of a lone exoplanet transiting its parent star. There are now 700 confirmed alien worlds orbiting other stars (ESO)

On Friday, the Extrasolar Planets Encyclopedia registered more than 700 confirmed exoplanets. Although this is an amazing milestone, it won’t be long until the “first thousand” are confirmed.

There are now more than 700 confirmed exoplanets in the database. The latest addition is the planet HD 100655 b.
– announced via the Exoplanet iPhone app

Only two months ago, the encyclopedia — administered by astrobiologist Jean Schneider of the Paris-Meudon Observatory — registered 600 confirmed alien worlds. Since then, there has been a slew of announcements including the addition of a batch of 50 exoplanets by the European Southern Observatory’s (ESO) High Accuracy Radial velocity Planet Searcher (or HARPS) in September.

The first exoplanet was discovered orbiting a Main Sequence star in 1995, and the rate of exoplanet detections has been accelerating ever since.

It is worth noting that hundreds more candidate exoplanet detections have been made, many of which have been spotted by NASA’s Kepler space telescope. Kepler is staring at the same patch of sky, waiting for alien worlds to cross the line of sight between their parent star and Earth, registering a slight dip in starlight brightness. The 1,235 candidates will be confirmed (or denied) as Kepler awaits future transits.

Detecting the slight dimming of starlight isn’t the only tool exoplanet hunters have to spot these alien worlds. The “radial velocity” method — as employed by systems such as the ESO’s HARPS — can detect the slight “wobble” of stars as orbiting worlds gravitationally “tug” on their parent stars. Both methods have their advantages and both are notching up an impressive exoplanet count. “Microlensing” has also been employed to spot a handful of exoplanets, as has direct imaging.

Exoplanetary studies are amongst the most exciting astronomical projects out there. Not only are we realizing there is a veritable zoo of worlds — some Earth-sized, others many times the mass of Jupiter — we are also pondering the most profound question: could extraterrestrial life inhabit these worlds?

For now, we have no clue, but life as we know it has a habit of springing up where we least expect it, it’s only a matter of time before we start to have some clue as to the existence of life as we don’t know it.

When an Astrophysicist Needs a Star Map

Stars of the Northern Hemisphere, Ashland Astronomy Studio

Stars of the Northern Hemisphere, Ashland Astronomy Studio

Imagine the scene: I’m having a romantic walk on a clear night with my wife along the beach. We see a brief flash of light and Deb says, “Hey, a meteor!” I then proceed to tell her that most meteors are actually no bigger than a grain of sand and they originate from comets, even though she already knew that. Feeling quite chuffed with myself that I was able to describe a nugget of atmospheric dynamics in 2 minutes, Deb then points up again and says, “There’s Orion. What constellation is that one?”

“Um. I have no idea,” I reply, feeling less smug. “I know how those things work, but I don’t know what they look like.”

I don’t own a telescope (yet) and I only took one course in university on practical astronomy, everything else was astrophysics. So the sad thing is that I know how stars work — from the nuclear fusion in their core to coronal dynamics (the latter of which I did my PhD in) — but if anyone asked me to point out a constellation or the location of a star… I wouldn’t have a clue.

Sure, there are the old favorites, like Orion, the Big Dipper (or Plough) and bright Polaris, but my expertise in night sky viewing is pretty limited. Although I’d usually refer any astronomy-related questions to BBC astronomy presenter (and Discovery News writer) Mark Thompson, I’d love to learn more. So, firstly, I needed a star chart.

Luckily, a few weeks ago, I received a random email from Erik Anderson from Ashland Astronomy Studio asking whether I’d like a copy of his company’s new star map poster. Being eager to boost my pitiful knowledge of the constellations, I jumped at the chance. Soon after, my poster arrived through the post.

Now this is where things got really cool. Although Erik had titled his email to me “Star Map with Exoplanet Hosts,” I’d forgotten about the “exoplanet” part. On the clear, yet detailed Ashland star map, all the major constellations and stars are plotted, along with the time of the year (in the Northern Hemisphere) they can be seen. But also, there’s a symbol representing the hundreds of stars that are known to have exoplanetary systems orbiting.

Over the last couple of weeks, I’ve been referring to my newly-framed star map, and can now confidently point into the sky, not only identifying the constellations but also some stars that possess exoplanets. Only last night, I pointed up in the general vicinity of the star 61 Virginis (near the blue giant Spica) and said, “That star has 3 worlds orbiting it.”

I’m not sure if Deb was overly impressed with my exoplanet knowledge, but I was happy to be smug again.

Although it’s only a very small part of an astronomer’s tool kit, a star map is essential. Although you can get apps for your iPhone, you can’t beat a poster that isn’t only functional, but also looks very attractive on your office wall.

The very cool Ashland Astronomy Studio Star Map can be purchased from Amazon.

Could Kepler Detect Borg Cubes? Why Not.

That's no sunspot.

"That's no sunspot."

Assuming Star Trek‘s Borg Collective went into overdrive and decided to build a huge cube a few thousand miles wide, then yes, the exoplanet-hunting Kepler space telescope should be able to spot it. But how could Kepler distinguish a cube from a nice spherical exoplanet?

With the help of Ray Villard over at Discovery News, he did some digging and found a paper dating back to 2005 — long before Kepler was launched. However, researcher Luc Arnold, of the Observatoire de Haute-Provence in Paris, did have the space telescope in mind when he studied what it would take to distinguish different hypothetical shapes as they passed in front of his theoretical stars.

The big assumption when looking for exoplanets that drift between distant stars and the Earth — events known as “transits” — is that the only shape these detectable exoplanets come in are spheres. Obvious really.

As a world passes in front of its parent star, a circular shadow will form. However, from Earth, we’d detect a slight dimming of the star’s “light curve” during the transit, allowing astronomers to deduce the exoplanet’s orbital period and size.

The transit method has been used to confirm the presence of hundreds of exoplanets so far, and Kepler has found over 1,200 additional exoplanet candidates. But say if astronomers paid closer attention to the shape of the received light curve; spherical objects have a distinct signature, but say if something looked different in the transiting “planet’s” light curve? Well, it could mean that something non-spherical has passed in front of a star. And what does that mean? Well, that would be a pretty convincing argument for the presence of a huge planet-sized artificial structure orbiting another star. Artifical structure = super-advanced alien civilization.

Arnold tested his theory that all manner of shapes could be detected by Kepler, assuming the transiting structure was on the scale of a few thousand miles wide. In this case, Arnold was testing his hypothesis to see whether we could detect an advanced civilization’s “shadow play.” Perhaps, rather than beaming messages by radio waves, an advanced civilization might want to signal their presence — SETI style — by blocking their sun’s light with vast sheets of lightweight material. As the shape passes in front of the star, the slight dimming of starlight would reveal an artificial presence in orbit.

By putting a series of these shapes into orbit, the aliens could create a kind of interstellar Morse code.

Of course, this is a rather “out there” idea, but I find it fascinating that Kepler could detect an alien artifact orbiting a star tens or hundreds of light-years away. Although this research is only considering orbital “billboards,” I quite like the idea that Kepler might also be able to detect a large structure like… I don’t know… a big Borg mothership. Having advanced warning of the presence of an aggressive alien race sitting on our cosmic doorstep — especially ones of the variety that like to assimilate — would be pretty handy.

Publication: Transit Lightcurve Signatures of Artificial Objects, L. Arnold, 2005. arXiv:astro-ph/0503580v1

Screaming Exoplanets: Detecting Alien Magnetospheres

Exoplanets may reveal their location through radio emissions (NASA)

Exoplanets may reveal their location through radio emissions (NASA)

In 2009, I wrote about a fascinating idea: in the hunt for “Earth-like” exoplanets, perhaps we could detect the radio emissions from a distant world possessing a magnetosphere. This basically builds on the premise that planets in the solar system, including Earth, generate electromagnetic waves as space plasma interacts with their magnetospheres. In short, with the right equipment, could we “hear” the aurorae on extra-solar planets?

In the research I reviewed, the US Naval Research Laboratory scientist concluded that he believed it was possible, but the radio telescopes we have in operation aren’t sensitive enough to detect the crackle of distant aurorae. According to a new study presented at the RAS National Astronomy Meeting in Llandudno, Wales, on Monday, this feat may soon become a reality, not for “Earth-like” worlds but for “Jupiter-like” worlds.

“This is the first study to predict the radio emissions by exoplanetary systems similar to those we find at Jupiter or Saturn,” said Jonathan Nichols of the University of Leicester. “At both planets, we see radio waves associated with auroras generated by interactions with ionised gas escaping from the volcanic moons, Io and Enceladus. Our study shows that we could detect emissions from radio auroras from Jupiter-like systems orbiting at distances as far out as Pluto.”

Rather than looking for the magnetospheres of Earth-like worlds — thereby finding exoplanets that have a protective magnetosphere that could nurture alien life — Nichols is focusing on larger, Jupiter-like worlds that orbit their host stars from a distance. This is basically another tool in the exoplanet-hunters’ toolbox.

Over 500 exoplanets have been confirmed to exist around other stars, and another 1,200 plus exoplanetary candidates have been cataloged by the Kepler Space Telescope. The majority of the confirmed exoplanets were spotted using the “transit method” (when the exoplanet passes in front of its host star, thereby dimming its light for astronomers to detect) and the “wobble method” (when the exoplanet gravitationally tugs on its parent star, creating a very slight shift in the star’s position for astronomers to detect), but only exoplanets with short orbital periods have been spotted so far.

The more distant the exoplanet from its host star, the longer its orbital period. To get a positive detection, it’s easy to spot an exoplanet with an orbital period of days, weeks, months, or a couple of years, but what of the exoplanets with orbits similar to Jupiter (12 years), Saturn (30 years) or even Pluto (248 years!)? If we are looking for exoplanets with extreme orbits like Pluto’s, it would be several generations-worth of observations before we’d even get a hint that a world lives there.

“Jupiter and Saturn take 12 and 30 years respectively to orbit the Sun, so you would have to be incredibly lucky or look for a very long time to spot them by a transit or a wobble,” said Nichols.

By assessing how the radio emissions for a Jupiter-like exoplanet respond to its rotation rate, the quantity of material falling into the gas giant from an orbiting moon (akin Enceladus’ plumes of water ice and dust being channeled onto the gas giant) and the exoplanet’s orbital distance, Nichols has been able to identify the characteristics of a possible target star. The hypothetical, “aurora-active” exoplanet would be located between 1 to 50 AU from an ultraviolet-bright star and it would need to have a fast spin for the resulting magnetospheric activity to be detectable at a distance of 150 light-years from Earth.

What’s more, the brand new LOw Frequency ARray (LOFAR) radio telescope should be sensitive enough to detect aurorae on Jupiter-like exoplanets, even though the exoplanets themselves are invisible to other detection methods. Nice.

As we’re talking about exoplanets, magnetospheres and listening for radio signals, let’s throw in some alien-hunting for good measure: “In our Solar System, we have a stable system with outer gas giants and inner terrestrial planets, like Earth, where life has been able to evolve. Being able to detect Jupiter-like planets may help us find planetary systems like our own, with other planets that are capable of supporting life,” Nichols added.

Although Nichols isn’t talking about directly detecting habitable alien worlds (just that the detection of Jupiter-like exoplanets could reveal Solar System-like star systems), I think back to the 2009 research that discusses the direct detection of habitable worlds using this method: Aliens, if you’re out there, you can be as quiet as you like (to avoid predators), but the screaming radio emissions from your habitable planet’s magnetosphere will give away your location…

Sometimes, You Just Have To Make Chocolate Mars Rover Cake

It's a chocolate Mars rover! Photo credit and cake-making skills: Will Gater

It's a chocolate Mars rover! Photo credit and cake-making skills: Will Gater

OK, so Astroengine has been a little quiet of late due to some uber-cool space news writing over at Discovery News, but to kick off an era of increased productivity (and not just Photoshop fun), I just had to share this superb chocolate-covered tribute to Mars Exploration Rover Spirit.

Created by my mate Will Gater, science writer and editor of Sky at Night Magazine, this is Mars rover Spirit, complete with silica-churned (white chocolate) Mars regolith in its tire tracks. I’ll be back in the UK next week Will, I hope you saved me a slice!

Latest news on Spirit: Mars Rover Down? Spirit Stays Silent

Speaking of Mars rovers, in case you missed it, I had the awesome fortune to visit the next Mars rover to be launched to the Red Planet later this year. Seeing the nuclear-powered, laser-toting, car-sized rover up close is something I’ll never forget. For more, take a look at the Discovery News slide show I created with pictures from my NASA Jet Propulsion Laboratory adventures.

This is me, in the NASA JPL clean room housing Mars rover Curiosity. As you can see, I'm very happy to be there.

This is me, in the NASA JPL clean room housing Mars rover Curiosity. As you can see, I'm very happy to be there.

What Happened to Mars Rover Spirit?

“A big rusty transporter came over the hill and the Jawas sold it for scrap metal…” — Paul Quinn

NASA is giving Mars rover Spirit one more month to signal that she’s still alive before search operations are scaled back and attention shifted to her sister rover Opportunity. Unfortunately, the prognosis isn’t good. It’s been a little over a year since Spirit last communicated and it’s looking increasingly likely she’s succumbed to a lack of energy and freezing conditions on the Martian surface.

But… something else might have happened.

“A big rusty transporter came over the hill and the Jawas sold it for scrap metal…” — Paul Quinn (via Facebook)

It’s not as if it hasn’t happened before, in a galaxy far, far away…

Credits: Main Mars vista with Spirit superimposed: NASA. Jawa sandcrawler and Jawa figures: LucasArts. Edit: Ian O’Neill/Astroengine.com. Inspiration: My mate Paul Quinn!

The Ultimate Paternity Test: Are We Martian?

"Dad?" A scene from War of the Worlds.

This rather outlandish, sci-fi notion comes straight from the fertile minds of researchers from MIT, the Massachusetts General Hospital and Harvard University who are proposing a biology experiment that could be sent on a future Mars surface mission. If their hypothesis is proven, we wouldn’t only have an answer for the age old question: Are we alone? but we’d also have an answer for the not-so-age-old question: Did life from Mars spawn life on Earth?

The idea goes like this: countless tons of material from Mars has landed on Earth. We know this to be true; meteorites have been discovered on Earth that originate from the Red Planet. These rocks were blasted from the Martian surface after eons of asteroid impacts, and the rocks then drifted to Earth.

If there was once life on Mars — a concept that isn’t that far-fetched, considering Mars used to boast liquid water in abundance on its surface — then perhaps some tiny organisms (not dislike the hardy cyanobacteria that is thought to have been one of the earliest forms of life to evolve on our planet) hitched a ride on these rocks. If some of these organisms survived the harsh conditions during transit from Mars to Earth and made it though the searing heat as the meteorite fell through our atmosphere, then perhaps (perhaps!) that is what sparked life on Earth.

You may have heard a few variations of this mechanism, it is of course the “panspermia” hypothesis. Panspermia assumes that life isn’t exclusive to just one rocky body like Earth, perhaps life has the ability to hop from one planet to the next, helped on its way by asteroid impacts. Not only that, but perhaps (perhaps!) tiny microorganisms could drift, encased in interstellar dust, akin to pollen drifting in the wind, seeding distant star systems.

Naturally, when considering the distance between the planets (let alone the light-years between the stars!), one might be a little skeptical of panspermia. But it certainly would help us understand how life first appeared on Earth. After all, it’s not as if the solar system has a natural quarantine system in place — if Mars had (or has) bacteria on its surface, perhaps they have been spread to Earth, like an interplanetary flu bug. Also, as experiments are showing us, microorganisms have an uncanny ability to survive in space for extended periods of time.

So, according to my esteemed Discovery News colleague Ray Villard, the MIT team led by Christopher Carr and Maria Zuber and Gary Ruvkun, a molecular biologist at the Massachusetts General Hospital and Harvard University, are proposing to build an instrument to send to Mars. But this instrument won’t be looking for signs of life, it will be testing the hypothetical Martian DNA and RNA. Should this interplanetary paternity test prove positive, proving a relationship between Earth Brand™ Life and Mars Brand™ Life, then this could be proof of some extraterrestrial cross-pollination.

Although this is complete conjecture at this time, as there is no proof that life has ever existed on Mars (despite what research in dodgy research journals tell us), it is certainly an interesting idea that would not only test the hypothesis of panspermia, but also give us a clue about the potential human colonization of Mars.

To quote Ray:

This could give us pause about sending humans to a germ-laden alien world. It would be an ironic twist on the H.G. Wells classic 1898 novel “The War of the Worlds,” where invading Martians succumb to the common cold from Earth microbes.

See, Wells’ Martian warriors should have done genome testing first.

Ingredients for Life on Gliese 581g?

Credit: Lynette Cook

Just in case you haven’t heard, astronomers have released news about an “Earth-like” exoplanet orbiting within the “Goldilocks zone” of a star some 20 light-years away. This is awesome, but does it mean Gliese 581g is habitable? Does it mean life is already slithering across its surface?

Judging by an exuberant claim by Steven Vogt, professor of astronomy and astrophysics at University of California Santa Cruz, one would think we now know there’s life on this strangely familiar world.

“Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say that the chances for life on this planet are 100 percent. I have almost no doubt about it,” Vogt told Discovery News when the announcement broke on Wednesday.

100%?

Why did he say that his personal view was that the chances for life on Gliese 581g are 100%? At first glance, it is easy to see where he’s coming from.

Goldilocks Zone

Firstly, the exoplanet orbits close to a small red dwarf star (called Gliese 581), with a fast-paced orbit of 37 days. This is important as the energy output of a red dwarf is tiny when compared to our Sun (which is a yellow dwarf star, in case you were wondering) — to receive an equivalent amount of heating as the Earth, Gliese 581g needs to be much closer to its star.

Also, it isn’t orbiting too close. It is within the habitable zone (or the “Goldilocks zone,” i.e., a zone that’s not too hot or too cold) of the system. Therefore there’s a high probability that if water is present on its surface, it’s likely to be in liquid form. The presence of liquid water would be exciting as Earth Brand™ life likes liquid water.

Secondly, Gliese 581g is small for an exoplanet discovered thus far. Weighing in at a minimum mass of 3x that of the Earth, it could certainly have some Earth-like qualities. This has another implication; the world has enough gravitational oomph to hold onto an atmosphere — another ingredient that life seems to like (assuming it’s not of the bone-crushing, lead-boiling, Venus-type atmosphere).

It’s Complicated

But there’s a few complications. To be within the habitable zone of its parent star, Gliese 581g will be “tidally locked.” This means that one side of the exoplanet will always be facing the star. On the far side (or, indeed, the “dark side”) it will be cold whilst the near side will always be hot. Having one perpetual day doesn’t sound very Earth-like to me. But there is an upside to this strange orbit.

“This planet doesn’t have days and nights. Wherever you are on this planet, the sun is in the same position all the time. You have very stable zones where the ecosystem stays the same temperature… basically forever,” Vogt said. “If life can evolve, it’s going to have billions and billions of years to adapt to the surface.”

So a tidally-locked planet could have a stable atmosphere and perhaps life could evolve as a result. What could be considered to be a negative has just become a positive.

With all this good news, why wouldn’t life be thriving on this world?

Unknowns and Assumptions

There’s still a lot of unknowns and assumptions being made. For a start, the presence of Gliese 581g was detected by measuring the “wobble” of the star as the exoplanet orbits (its gravity tugs on the star as it circles). Therefore its mass and orbital radius can be derived. But we have no information about its atmosphere; the world doesn’t pass in front (or “transit”) the star from our perspective, so we can’t get a peek into its atmosphere.

Therefore we have zero clue as to whether it even has an atmosphere. It might not have an atmosphere, but then again it could have a very thick atmosphere — two extremes that would would put a stop to any Earth Brand™ life evolving. Also, we have zero clue if there’s any water there, it’s just guesswork that suggests there might be. There’s also the huge unknown as to whether life is ubiquitous in the cosmos or not.

Bread in the Oven

It’s a bit like baking a loaf of bread when you have all the necessary ingredients to make bread, but you have no clue about what quantities to use. Gliese 581g appears to have most of the ingredients for life (and with a few assumptions, it has all the ingredients for life), but we only have a general idea as to what quantities these ingredients come in.

If you threw flour, water and yeast straight into the breadmaker in random quantities, would you get a loaf of bread? What if you forgot to add the yeast?

Gliese 581g is that breadmaker. Unfortunately we have no clue if it can make bread.

For more on this incredible discovery, read Irene Klotz’s Discovery News article: “Earth-Like Planet Can Sustain Life