Tag Archives: extraterrestrial

39 Light Years: Part One

Image: Ben Roberts. Produced with Universe Sandbox

Sometime in the early 2000s, this place was still a speck of data in some astronomers brain. The announcement of a system of seven earth-sized planets was pretty big. The further revelation of three of those worlds sitting within their stars habitable zone was the icing on the cake.

As the first intelligent explorers approach TRAPPIST-1e, we present to you these images: the culmination of decades of waiting, hoping that return transmissions from the TRAPPIST-1 mission wouldn’t get lost in interstellar space. There were those who worried that anything beamed back by the missions wouldn’t even make it out of the system. TRAPPIST-1 is a red dwarf star: a tiny relic of a thing but incredibly ancient. Age estimates range from 8 to 12 billion years old. Red dwarf stars tend to be nasty little suckers, and TRAPPIST-1 is no exception. Extreme solar flare activity sometimes hits the system, as the parent star has a tantrum. Communication from the system is nothing short of a miracle. Nevertheless, here are some of the better images we’ve managed to glean from the stream of data being sent back. Thirty nine years worth. Thirty nine years of waiting.

Approach: A New Red Planet

The very first direct images of TRAPPIST-1 and it’s rocky retinue were messy little blobs of pixels.

Of course, many exoplanets (and exomoons) had been imaged directly using a variety of techniques. The use of coronagraphs to scrape together images from points of light across impossible distances was revealing new vistas for a long time. The following image was taken all the way back in 2004:

A disc of debris around the red dwarf star AU Microscopii. Image: Hubblesite.org

Of course, progress marched on, and as missions approached the system the world waited for new images. A first blurry image sped across the galactic neighbourhood:

A TRAPPIST-1 planet caught in transit across the host star. The faded object to left of centre is an artifact of the imaging process.

This image was a first test. As the mission approached the system, we began seeing more. High quality imaging was held off until final approach, in the interests of energy efficiency.

An infrared and monochromatic direct light image, taken from a distance of approximately 11 AU. Images: Ben Roberts

TRAPPIST-1e was waiting for us.

Image: Ben Roberts

Imaging of exoplanets is explored in a new video, presenting the concept of coronagraphy. Help astrobiology reach the world (this and others) by checking it out. Subscribe and share if you like.

This post is the first of a series taking us on a trip to a real alien world, and speculating on just what it could be like, using real world astrobiology. I hope you like it!

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The Last Ecosystem

Fragments of ancient life, spotted by explorers in a new system..

I’ve been working on some more astrobiology art. It’s taken on a life of its own, and I have to say, I’m paying more attention to these images than my YouTube channel!

I’ve been enamoured lately of dead or dying worlds. A recent video on my channel talked about the amazing possibility of limestone fragments orbiting the white dwarf star SDSSJ1043+0855. Ever since reading of this it’s captured my imagination. The notion that life has existed long ago, possibly before life began on earth bears thinking about.

Limestone is a mineral produced primarily by organisms which produce shells, using a matrix that incorporates calcium carbonate. In the early days of multicellularity, as the predator-prey paradigm took hold of Darwinian evolution, an ancestor of today’s molluscs discovered how to make use of an upsurge in calcium levels in the oceans. It used it to produce a protective suit of armour. This trick was so successful that molluscs became incredibly abundant. So abundant, in fact, that their remains ended up as vast deposits of limestone.

To the present day.

Using spectroscopy, the three elements that comprise calcium carbonate: carbon, oxygen and calcium have been detected in the upper atmosphere of this particular white dwarf. By themselves they aren’t a smoking gun. It’s also fair to point out that limestone can form abiotically. Limestone deposits in subterranean caves are one example. However, the vast majority of limestone on earth is biologically produced.

The “limestone” orbiting this star is believed to be embedded in the fragments of a large rocky object. We know nothing about this world, only that it probably existed and (possibly) limestone comprised part of it. Is it a fossil, spotted across the light years by modern humans? How long ago did this world harbour life? White dwarf stars (which aren’t technically stars! Find out why here) have been discovered which are nearly as old as the universe.

Earth is 4.6 billion years old. What of the world currently being torn up by the immense gravity of this white dwarf?

Dead worlds could be scattered across the galaxy.

It would be interesting to look forward and see how our own world eventually will die. For now, this white dwarf star and it’s companions are a way to look ahead at what may befall us. It’s believed that eventually the earth will become incapable of supporting life, as the sun begins to undergo senescence billions of years from now. What iterations will the terrestrial biosphere take over such a vast stretch of time? Will life start over? Are these “fossil” fragments within this unnamed rocky world pieces of its last ecosystems?

What will the last ecosystem on earth be?

Sailed the Ocean Blue

It’s been estimated that a good percentage of planets beyond our solar system may be water worlds.

We here on mother Earth like to think of our blue green marble as a water world. Indeed it is watery, and water is pretty much the reason anything lives here at all. That’s why astrobiologists naturally seek signs of water on exoplanets. “Follow the Water” is a central tenet in the search for extraterrestrial life.

But compared to some worlds, earth really isn’t that waterlogged at all. It’s 0.002 percent water by mass. Only a tiny fraction of that water is available to terrestrial life. That water which isn’t directly involved in biological processes is linked to them, linking life to the planet via seasons and climate.

Some exoplanets are believed to be up to fifty percent water! These are true ocean worlds. To date, up to thirty five percent of exoplanets larger than may be covered by vast layers of water that may or may not harbour life. The jury is well out on that, but the idea is intriguing (and tempting) as the traditional definition of habitable zones is being stretched and reinterpreted.

A water world with a thick atmosphere of steam.

For now, we have only our imaginations with which to explore these worlds…

An aerial view of remote coastline on a hypothetical watery exoplanet.

A new video!