Tag Archives: exoplanets

TRAPPIST-1: A Solar System of Earth-Sized Planets

The announcement that NASA hinted about being a major discovery related to planets orbiting another star turned out to actually be pretty major. In many cases, we’ve seen announcements of huge planets, single Earth-sized planets, or a super-Earth in the habitable zone around a star. This time, it’s even more significant.

TRAPPIST-1 is a very cool and small red dwarf star 39 light years away. Not only does it have one Earth-sized planet, but it has seven. And it’s not just one of them in the habitable zone, it’s three. How’s that for amazing?

Two were originally discovered by The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile, then confirmed by NASA’s Spitzer Telescope. But Spitzer discovered a further five planets. When the James Webb Space Telescope is in operation, it will be used to study these planets even further. We may be able to discover the atmospheric composition, determining if they’re potentially habitable.

As these are planets orbiting a red dwarf, they are close to the star, with the outer planet having an orbital period of only 20 days. This means that they’re likely to be tidally locked, with one side of each planet facing the star. They don’t have enough information about the outer planet to determine its exact size, but scientists guess that it may be icy.

NASA released this video on the planets:

What do you think of this news? Let’s talk about it in the comments section below.

NASA’s Big Kepler Announcement: It’s Not Aliens

NASA announced recently that they would be making a big announcement today about a discovery by the Kepler Telescope. Well, the announcement is that 1,284 planets have been discovered. And what’s really big is that there’s a 99% chance that they are planets. Here’s a graph of the planets that have been discovered so far.

keplerplanets
The known planets discovered so far with Kepler. Credit: NASA Ames/W. Stenzel

Of course, before the announcement was made, many people were speculating on what the announcement would be. This includes science groups on Facebook. Groups that I would think would know better. You see, this is what people were saying: NASA is going to announce aliens!!!!

First of all, science groups were saying this. Really? Too many science groups are promoting both junk science and hype.

Secondly, NASA is not going to announce aliens when they said they were talking about a Kepler discovery. Kepler is not designed to detect life. It cannot detect life. Kepler deals with detecting planets that cross in front of their stars. That does not include detecting alien civilisations or even life. Further observation is required to study the atmosphere, and even then, we can’t be certain if there’s life.

However, several of the new planets are fairly close to Earth-sized and in the habitable zone of their stars. That is exciting. Those planets will be studied to pinpoint their sizes and atmospheres.

So, relax. No aliens will be discovered by Kepler. I don’t know why people even thought that.

Helping Name Exoplanets

Did you know that you can help to name some extrasolar planets? No? Well, you can.

The IAU (International Astronomical Union) is asking for the public’s help in naming the planets that orbit twenty different stars. And just who is the IAU? Well, it’s the organisation that’s responsible for the naming of planets, stars, asteroids, moons, and so on. That means that these names that you can vote on may become completely official.

So, how can you vote? Well, just go here, and vote on your favourite names. Many of these planets are very well-known by astronomers now, and are quite significant, as some of them were firsts.

One of the best-known stars in this list, Fomalhaut is also relatively nearby at only 25 light years. One of the planets you can help name is Fomalhaut b.
One of the best-known stars in this list, Fomalhaut is also relatively nearby at only 25 light years. One of the planets you can help name is Fomalhaut b.

It’s quite exciting that we’re now getting into the naming of exoplanets. There are nearly 2,000 confirmed planets with nearly 5,000 unconfirmed. That’s a lot of names to give.

I’m definitely taking my time to vote on my favourite names. Some of them I don’t think are appropriate or even related to the star or constellation. Some shouldn’t even be planet names, I think. But there are a handful that people put a lot of thought into and even linked it to mythology, which is the standard for naming a body in the solar system. I was surprised to see so many Japanese names available to vote on. Must have been many Japanese people interested in this.

Are you going to vote?

Dreaming of an Exo-Planetary Sunset

Here on Earth, we can get some spectacular sunsets.  Just look at this.

20150216-010932-4172100.jpg

That’s Mt. Fuji behind the Tanzawa Mountains.  I can see this view often.  Nice, isn’t it?

But with all the work I’ve been doing on Ariadne recently, I’ve been thinking about what it would really look like on another planet.  Check out some of this art here. And here, too. There’s some great looking art there.  I wish I could do that.  I’ll be doing sketches, but nothing like that.

What would Ariadne’s sunset look like?

The Planet We Waited For

With all the worldbuilding posts I’ve been writing, this announcement was perfect timing.  I’m talking about Kepler-186f, the planet discovered, and since confirmed by two separate telescopes, orbiting a red dwarf star nearly 500 light years away.  It’s a bit bigger than the Earth, and it orbits at about a third the distance from its star than Earth does from the Sun.  This infograph shows you everything.

Facts about planet Kepler-186f.

Source SPACE.com: All about our solar system, outer space and exploration.

This is an incredible discovery, although it was expected eventually.  But now we’ve found it, a world very similar to Earth in size and temperature.  It’s likely to be able to have liquid water on its surface.  As it’s larger than Earth, the higher gravity could hold onto a more dense atmosphere.  This would help, as it’s closer to the outer edge of the habitable zone of the star, so some greenhouse effect would be useful.

Of course, more work needs to be done.  We don’t actually know anything about the atmosphere or the surface of the planet.  We know its radius and mass pretty well, but much more direct observation of its spectrum needs to be made.

I’m curious about when the first science fiction novel will be written about this planet.

Who’s excited?

A Planetary Neighbourhood for Ariadne and Earth

With my recent posts about choosing a star and creating a planet for world-building, I thought I should flesh out the planets around the stars that are near Earth and Ariadne.  Think of it as alternate candidates for colonisation.

To do this, I’ll use the same equation to determine temperature on the planets.  The stars will be real.  The planets will be entirely fictional, unless the host star already has discovered planets.  I’ll create entire planetary systems, even for those stars that we normally wouldn’t consider good candidates for habitable planets.  There’ll be a lot of red dwarfs, though.

I’ll be using these for a future purpose in the Ariadne universe.  If I decide to have the people of Ariadne take to the stars in future books down the road, I’ll use this information for more stories.

World-Building: Choosing a Star

This is the first post in a series of posts in which I will describe my method to creating a new world for science fiction.  Back in November, I described how to colonise a world, but this is different.  While that is more about the process of a world being selected and colonised, this is about how to create the world.

Choosing a Star

I’m not even going to look at the planet to begin with.  What we need for a plausible habitable world is a star that can host it.  I’ll look at the various types of stars and their suitability to host a habitable world.

First of all, we can safely say that giant and supergiant stars are not suitable.  They are very short-lived, and while they used to be smaller stars that were stable, their giant size has swallowed up any planets that would have been habitable.  More distant planets may have become habitable, but with a giant star’s unstable atmosphere and impending destruction, it’s not a good idea to use these stars, unless your story has some kind of outpost on an outer planet.  But I want to discuss habitable planets that you can breathe the atmosphere.

Neutron stars are also out.  The radiation is incredibly strong and would kill everything.  But planets do exist around neutron stars.

The Hertzsprung-Russell Diagram showing the main sequence stars down the middle of the chart. This image is used under the Creative Commons license, and was created by Richard Powell.
The Hertzsprung-Russell Diagram showing the main sequence stars down the middle of the chart. This image was found at Wikipedia, and is used under the Creative Commons license. It was created by Richard Powell.

White dwarf stars are the dead remnant of regular main sequence stars.  Our sun will become one in a few billion years.  After a giant star has expelled its atmosphere and collapses into a white dwarf, it can form new planets close in, as there’s a lot of debris from the former star.  However, the habitable zone is so close to the star that it would experience very strong tides and make the orbit potentially unstable.  This doesn’t mean that a white dwarf can’t support a habitable planet.  I would suggest that it’s unlikely, though.  It is possible, so go ahead and make your planet’s star a white dwarf if you like.

The best kinds of stars to use are main sequence stars.  There are several stellar types, and they’re nice stable stars undergoing hydrogen fusion in the core.  They range from very hot to very cool, with spectral types O B A F G K M.

O, B, and A type stars are very hot.  They’re also large.  They have a habitable zone farther from the star, but the problem with a habitable planet developing is that it doesn’t have much time.  These stars are quite short-lived.  O stars are the most massive, and they burn through their hydrogen very quickly.  A planet would have no time to develop a habitable atmosphere.  These stars are only around for a few million years before going supernova.  B type stars aren’t much better.  They are also extremely hot and massive, and they’ll go supernova in a few million years, as well.  A type stars are around for a few hundred million years.  They’re a safer bet, but unlikely to develop much in the way of life.  There have been planets found around these stars, but as it takes time for life to evolve, and for a breathable atmosphere to develop, it would not be a good place for intelligent alien life or a human colony to easily be established.  O, B, and A type stars represent less than 1% of the stars, so they are not common.

The best types of stars for more Earth-like planets would be F, G, and K type stars.  The Sun is a G2 star, which means it’s slightly cooler and smaller than an F type star, but quite close to that type.  F type stars have a shorter life than G type stars, but should have enough time for life to develop and to have a habitable planet.  These are good stars.  Of course, G type stars are suitable.  K type stars are smaller and cooler than our sun, so have a habitable zone closer to the star.  However, they are around for a lot longer than G stars.  The year may be shorter, but the lifespan of a planet is far longer.  Excellent candidate for a planet.

Finally, we have the M type star.  These are red dwarf stars, and make up 76% of the stars in our galaxy.  As they are the most common type of star, they are also the most likely to find planets.  The habitable zone is very close to the star.  This poses a problem.  As it’s so close to the star, the planet could be tidally locked.  One side is always facing the star, while the other is facing away.  The sunlit side is always hot, while the dark side is always incredibly cold.  Atmospheric circulation could lessen this a bit, but expect both extremes to be uninhabitable.  The fringe around the terminator (the area where you have a permanent sunset/sunrise) could be habitable.  This would give a very interesting environment for life.  No day and night cycle.  The life that would evolve there would be quite different.  For a human colony, it’s quite feasible.  Just don’t venture too far into the sunlit side, and be prepared for deadly cold in the night side.

F, G, and K main sequence stars would be the best, but M type red dwarfs would make a very interesting setting for a science fiction story.  Any other kinds of stars are risky or even suicidal (neutron stars).

What I did

In the case of Ariadne, I chose a G type star that was relatively close to us, Beta Comae Berenices.  It’s 29.78 light years away, and is a G0 spectral type star.  It’s slightly hotter and larger than the Sun, but it has a similar habitable zone as the Sun.  It is about 1.5 billion years younger than the Sun, though.  We don’t know enough about how evolution happens on other planets, so it’s quite possible it could be faster or slower.  At an age of 3 billion years, our own planet Earth only had simple multicellular organisms and an atmosphere that wasn’t breathable, only 1% of today’s level of oxygen.  But who’s to say that it can’t happen faster on other planets?  On Ariadne, it was faster.  The scientists who studied the planet found that oxygen levels were comparable to the Earth’s so it was deemed a very good candidate for colonisation.  A space probe confirmed that.  Complex life was there, but this is for a later discussion on world-building.

I’m Going to Be a Student!

Well, sort of.  I’m actually going to be taking a couple of free university courses online at Coursera.

courseraThe first one starts on January 20, 2014, and is only 5 weeks long.  I’ll be studying about astrobiology and the search for extraterrestrial life.  I’m using this as research for Ariadne, and hope to get some good information about it.  It’s taught by a university professor at the University of Edinburgh in Scotland.

The second one starts in March (exact date unknown), and is about the diversity of exoplanets.  Also being used as research for my books.  This one is taught by 7 professors at the University of Geneva in Switzerland, and it’ll last 6 weeks.

Each of these courses will only require 2-4 hours of work a week, including homework, watching videos, and quizzes.  At the end of each course, I’ll actually get a Statement of Accomplishment from the universities and signed by the professors.  What does this mean?  Absolutely nothing.  But it’ll be useful information, and will help me improve the science of my novels.

Plants on alien worlds

Do you ever wonder what plants on alien worlds would look like? The answer may be in the type of star it orbits.

Red dwarf stars give off little light and heat, so plants would need to absorb as much light as possible, according to a preview of an article I read online. It makes sense that they would appear black.

F type stars are quite bright and would likely need to reflect a lot of light. Shiny leaves? But what colour would they be? Apparently, green, yellow or red. Maybe anything in between, too.

This makes it interesting for creating new worlds for science fiction. Knowing the spectral type if the star gives you an idea about what colour the plants may be. Going beyond that, it may give an idea about what wavelengths animals can see.

In my planned sci-fi novel, the star I chose is a bit younger than the sun, but a G type star. The plants are likely to be green.

But I’d love to see planets with plants of many other colours.

Do aliens exist?

As a science fiction fan, I want to see aliens. I want them to exist. As someone with a degree in physics and astronomy, I have no doubt that life is extremely likely to exist on another planet somewhere in the universe.

With the large number of planets being discovered these days, it’s becoming apparent that small rocky planets are very common in our relatively local stellar neighbourhood. I believe most scientists agree that life in some form is most likely out there somewhere.

The question is, will we ever meet them? The vast distances and high speeds required to travel between the stars makes it extremely unlikely that we will meet them. The only way is if one of us develops a propulsion system that can take us to relativistic speeds without killing us with the immense g-force experienced with the high acceleration required. Or we can use sleeper ships or generation ships. In any case, we need some pretty good technology and the resources to construct such an enormous ship.

Could we communicate with them? Could we breathe the same air? Could we tolerate the same temperatures? What do they look like? So many questions!

Could aliens already be here? Maybe, but how likely is it that an advanced species would exist nearby? We can’t be sure about this without more information and observation.

For now, we can always meet the aliens in science fiction.