NASA finds seven earth size planets, but are they anything like Earth?

Friday, 24 February, 2017

After days of keeping us in suspense about a new discovery, NASA let the cat out of the bag, in the early hours of yesterday morning. The TRAPPIST optic robotic telescope, located in Chile, recently identified a dwarf star, about forty light years distant from Earth, that is host to seven planets around about the same size as Earth.

Come on now, you didn’t think they were going to announce that an alien civilisation had been found, did you?

This is still a significant discovery though. Particularly as three of the seven bodies orbiting TRAPPIST-1 – the star also takes its name from the Belgian operated telescope – are within its solar system’s so-called Goldilocks, or habitable zone, an area capable of supporting life, that is neither too hot, nor too cold.

It is this bit that is especially of interest, as it means these planets may habour water in liquid form, and, as a result, potentially life of some sort. And that is obviously an exciting prospect. But talk we may one day be able to emigrate there is well wide the mark, to say the least.

There is, you see, a big difference between a planet that is “earth-like”, and one exactly like Earth. Or a planet that could be called an Earth twin, or Earth analog. For example, Proxima b, an exoplanet within the habitable zone around Proxima Centauri, the nearest star to the Sun, is considered to be earth-like, as it is a rocky, or terrestrial planet.

It might have some sort of atmosphere, and possibly there could be liquid water on its surface. But Proxima b may be far from habitable, at least as far as humans are concerned. As Proxima Centauri is a red dwarf star, which are relatively cool, Proxima b would need to be quite close, to be within the habitable zone.

This sort of proximity however could mean Proxima b is tidally locked, meaning the planet’s rotational period matches the time it takes to orbit the star. This result here is only one side of the planet would ever face the star.

Therefore, the sunny side of Proxima b would be quite warm, whereas the night side would be extremely cold. The only spots that might be conducive to life, would be near the day-night terminator. In addition, the planet is also exposed to stellar wind pressures far greater than those that Earth experiences.

Not all that earth-like, after all. So while some form of life may manage to eke out an existence there, it would hardly be suitable for human occupation. The same conditions could well apply to the planets within the Goldilocks zone of TRAPPIST-1, given it to is a relatively cool dwarf star.

At the very least, they’re quite possibly tidally locked. If we’re looking for a new planet to settle on then, it needs to be an Earth twin. This is a planet, as the name suggests, that is identical in almost every way to ours. And if there are at least one hundred billion planets in our galaxy, the Milky Way, then it stands to reason some proportion must be virtually identical to Earth.

But an Earth twin candidate needs to be more than a terrestrial planet, orbiting within the habitable zone of its solar system though. In their book, Rare Earth, published in 2000, US paleontologist Peter D. Ward, and Donald Brownlee, a professor of astronomy, outlined the criteria necessary for a planet to be classified as an Earth twin:

The right distance from a star; habitat for complex life; liquid water near surface; far enough to avoid tidal lock; right mass of star with long enough lifetime and not too much ultraviolet; stable planetary orbits; right planet mass to maintain atmosphere and ocean with a solid molten core and enough heat for plate tectonics; a Jupiter-like neighbor to clear out comets and asteroids; plate tectonics to build up land mass, enhance bio-diversity, and enable a magnetic field; not too much, nor too little ocean; a large moon at the right distance to stabilize tilt; a small Mars-like neighbor as possible source to seed Earth-like planet; maintenance of adequate temperature, composition and pressure for plants and animals; a galaxy with enough heavy elements, not too small, elliptical or irregular; right position the galaxy; few giant impacts like 65 million years ago; enough carbon for life, but not enough for runaway greenhouse effect; evolution of oxygen and photosythesis; and, of course, biological evolution.

That’s an extensive list. Some astronomers think two percent of the Milky Way’s planets may be Earth twins, meaning there could be two billion such bodies. Given the exacting conditions required for their existence though, I think the actual number may be far smaller.

It could a very long time, therefore, before any announcement is made regarding the discovery of a truly earth-like planet, that is, an Earth analog. It also means we have to take greater care of our own Earth. Clearly we’re not going to be emigrating anywhere else in any hurry.

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The Doomsday Clock now sits at two and half minutes to midnight

Friday, 3 February, 2017

The Doomsday Clock, originally developed by the Bulletin of Atomic Scientists in 1947, as a gauge of international events that are dangerous to the world, including a nuclear war, now sits at two and a half minutes to midnight.

This is the nearest that the clock has been to midnight in that last fifty years. It would seem various efforts to make the world a safer place are missing the mark.

Even if nuclear weapons did not exist, climate change and the accelerating loss of biodiversity are serious threats. Damage to ecosystems is already taking place; climate change is causing loss of life and property, as well as affecting natural systems. At the same time, the nations with nuclear weapons are still testing new devices and more sophisticated delivery systems.

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White silver and black lead, that’s the beauty of Science

Thursday, 22 December, 2016

Yes, there is beauty in science, as this footage of white silver and black lead, filmed through a microscope, during metal displacement reactions, demonstrates. This clip is from Beauty of Science, a China based educational project, that aims to raise awareness of the beauty present in science. A great idea.

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Redheads, an endangered species thanks to climate change?

Tuesday, 13 December, 2016

Climate change and redheads may not go together well. Scientists seem to be divided as to whether this might bring about a reduction in our numbers, or our eventual extinction. That’s a cheery thought. And that’s not even the half of it, if this list is anything to go by.

Sun cream is your oxygen. Some reported getting sunburnt when the moon is out. Another claimed to drink sunscreen for internal coverage. Factor 50 in winter is not uncommon.

On the flip side, redheads tend to age better than those with other hair colours. So, swings and roundabouts?

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The universe will end in a vacuum, a false vacuum

Tuesday, 25 October, 2016

Well, this is cheery. A false vacuum may bring about the destruction of the universe. And there’d be no warning that the end was nigh. The only upside is that the process can’t move any faster than the speed of light. So it may be billions of years, if ever, before the entire cosmos succumbs to a false vacuum.

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There’s a mere two trillion galaxies in the night sky. Possibly

Wednesday, 19 October, 2016

A paper recently published in the Astrophysical Journal suggests there may be ten times more galaxies in the universe than was thought. That would make for two trillion of them, including our family of stars, the Milky Way. Incredible.

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Is there life on Proxima b? Is there extraterrestrial life anywhere?

Friday, 26 August, 2016

It’s official. Apparently. It wasn’t on Tuesday, though. The existence of an exoplanet, known as Proxima b, that is located within the habitable zone of the Proxima Centauri solar system, that is situated about four light years from Earth.

So, might there be life of some sort there? For that matter, might there be life anywhere, beyond our solar system? Seth Shostak, Senior Astronomer at SETI Research, discusses the possibility.

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Are aliens trying to extinguish a star so we can’t see them?

Thursday, 11 August, 2016

Tabby’s Star, or KIC 8462852, to use its Kepler Input Catalog title, has been making headlines in recent months, on account of mysterious fluctuations in its brightness. Explanations have varied. Some astronomers think a swarm of comets orbit the star, dimming its light.

Others have suggested a Dyson Sphere, a large, artificial, structure that harnesses a star’s energy, may be present. Something that would point to the presence of extraterrestrial life. Further recent research into the star’s unusual behaviour, concludes that yes, the star is acting strangely, but still no reason is forthcoming.

Michael Byrne, writing for Motherboard, may have stumbled upon the answer, though. An alien intelligence is, you see, trying to extinguish the star:

Knowing that aliens are succeeding in quenching KIC 8462852 at a rate of approximately .34 percent per year, we have to ask why they are shutting down a primary energy source. The obvious answer is that they’ve realized that we Earthlings are on to them and are reentering this dimension via a sort of astroengineered “death star” portal-vessel to deal with the perceived threat (us!), but given that KIC 12557548’s distance from Earth is over 2,000 light-years, we have to ask how they would even know? How aliens determined that they were being observed by humans before humans even had telescopes or cars will without a doubt be the astrophysical mystery of the coming decades.

Remember, you heard it here first.

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Life on Earth is premature, that’s why we’re alone in the cosmos

Thursday, 4 August, 2016

Since the Fermi Paradox intrigues me. Life on Earth is premature. A fluke perhaps. The universe is still relatively young, that’s why we haven’t detected signs of intelligent life elsewhere.

If we compare the present age of the universe, against its projected lifespan, possibly twenty trillion years, then it has an age comparable to an eighteen day old child, who would be expected to live for seventy years. Eighteen days. That’s pretty young. The cosmos isn’t yet mature enough to be teeming with life.

The dominant factor proved to be the lifetimes of stars. The higher a star’s mass, the shorter its lifetime. Stars larger than about three times the sun’s mass will expire before life has a chance to evolve. Conversely, the smallest stars weigh less than 10 percent as much as the Sun. They will glow for 10 trillion years, giving life ample time to emerge on any planets they host. As a result, the probability of life grows over time. In fact, chances of life are 1000 times higher in the distant future than now.

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There’s more science to a cup of coffee than meets the eye

Tuesday, 19 July, 2016

The Melbourne based Australian Coffee Science Lab, headed up by Dr Monika Fekete, is dedicated to improving the coffee roasting and brewing process. Yet better coffee is on the way.

“Science is very good at finding cause and effect,” Dr Fekete says. “You make a perfect cup or a perfect roast, but it’s a bit of luck, a matter of trial and error. By doing coffee science, we’re taking some of the guesswork and mystery out of making good coffee.”

I wonder if they have any vacancies for field testers?

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