Comments on: Exoplanet in a triple star system smack dab in the habitable zone

By: Alpha Centauri and the complexity of the ‘habitable zone’

Alpha Centauri and the complexity of the ‘habitable zone’ — Sun, 12 Feb 2012 19:35:08 +0000

[...] questions given the context of recent discoveries such as a planet in the habitable zone of the triple star system GJ 667. There was also a recent study presented at the AAS meeting about the effects of tidal heating on a [...]

By: Pete Down Under

Pete Down Under — Sun, 12 Feb 2012 07:59:34 +0000

Chris (#27) and amphiox… You would only notice a *change* in velocity, not the absolute velocity. I learned this the other day, after reading Brian Greene’s excellent discussion of special (i.e. constant-velocity) Relativity.

So yeah, the only weird stuff you’d notice would be collisions with interstellar stuff with a different relative velocity to yours. Like neutrinos (there’s no charge for them!), solar wind particles, teapots, etc. Except for neutrinos, of course. Confused? So am I…

By: Rich

Rich — Sat, 11 Feb 2012 11:44:07 +0000

Great Story!!!
You mentioned that a cloudy planet can hold heat better by way of the greenhouse effect. That is at best, an over-simplification. Actually, the greenhouse effect is not related to the clouds but instead by the composition of the atmosphere. For example, CO2 and more effectively, CH4 (methane) are powerful greenhouse gases. They also do not form clouds here on Earth. Our clouds are H2O and will reflect a great deal of incoming solar radiation, preventing that radiation from reaching the deep atmosphere or the Earth’s surface, there-by providing a cooling effect.
A simple experiment involving 2 identical soda bottles can be done to prove this. Place a thermometer in each. Cap the first with only air and the second after blowing in CO2 or some other greenhouse gas. Place both in a sunny spot and watch the second bottle get hotter quicker. This depends only on the composition of the gas. Notice there are no clouds in either bottle.
Venus has a permanently clouded sky and a run-away greenhouse effect but it’s atmosphere is very high in the greenhouse gas, CO2. I would submit that it is the greenhouse gas in the atmosphere and not the clouds that keep it so hot there.
It would be impossible to say which direction a planet’s clouds would push the HZ envelop without knowing more about the composition of those clouds (and the rest of the atmosphere).
Still, great article and nicely written. Thanks!!!

astronaut2k05

By: prentice

prentice — Fri, 10 Feb 2012 23:06:03 +0000

Beam me aboard scotty. I’d believe Japanese Godzilla movies were real before i’d beleive some of the garbage I hear coming out of the mouths of our so called scientists. I think they watch too much television!

By: Friday Links

Friday Links — Fri, 10 Feb 2012 15:27:50 +0000

[...] dwarf star orbiting billions of miles around the other two stars – it’s a bit odd. Phil Plait gives a good summary. You can find some nice hard numbers at this exoplanet catalog. For the best diagrams and [...]

By: Nigel Depledge

Nigel Depledge — Fri, 10 Feb 2012 13:06:44 +0000

Charles B (52) said:

The universe is a big place, almost infinite

What does “almost infinite” mean, please?

I was under the impression that “infinite” was a Boolean operator.

The chances of intelligent life existing must be more than 1:infinity-1

Why must they?

Earth is not the only place inhabited by intelligent life.

There is no evidence for this, AFAICT.

Humans do not have the sole claim to “intelligence”.

I have yet to see it proved conclusively that humans, on average, have any claim to intelligence.

By: Nigel Depledge

Nigel Depledge — Fri, 10 Feb 2012 13:03:01 +0000

Infinite 123 Lifer (51) said:

However, is there the opposite of speed or velocity in mathematics?

Speed is a scalar quantity so it has no opposite.

Velocity, however, is a vector so it has a direction as well as a magnitude. The opposite of velocity (negative velocity) is, prosaically, speed in the opposite direction.

By: Nigel Depledge

Nigel Depledge — Fri, 10 Feb 2012 12:50:28 +0000

Gunnar (87) said:

@Nigel #86, this has been a pet peeve of mine too.

Solidarity, sibling!

By: Nigel Depledge

Nigel Depledge — Fri, 10 Feb 2012 12:47:20 +0000

Chris (27) said:

Complete layperson here- what does a 28 day orbit do to its atmosphere? i.e. does it get blown off at that speed? Compressed in the direction of it’s orbit?

Since the planet is moving through the vacuum of space, nothing happens to the atmosphere as a result of the panet’s orbital velocity.

However, a planet’s atmosphere will be affected to some extent by the solar wind from the parent star. If the planet has a magnetic field, then its atmosphere will be mostly unaffected by this. If the planet has no magnetic field (or a trivially weak field), then a strong solar wind could eventually strip the lighter elements from the atmosphere. This is an oversimplification, but I hope it gets the basic idea across.

By: Gunnar

Gunnar — Fri, 10 Feb 2012 11:01:33 +0000

@Nigel #86, this has been a pet peeve of mine too. It is somewhat suprising to me how many people (some of whom seem otherwise quite articulate and intelligent), who post to various blogs I have visited, repeatedly make this same error. I suppose that one of the things that leads people into this error is the fact that the past participle of “to read” is spelled “read”, though it is pronounced “red.” One can be easily misled into the error of thinking that “to lead” necessarily follows that same pattern if enough years have elapsed since one last reviewed the grammar and spelling that should have been learned in primary school.