Proxima B

[Mark Isaak]

Good news for panspermists and future space travelers. An earth-like
planet has been found around Proxima Centauri.

http://www.thescinewsreporter.com/2018/10/its-official-researchers-have.html

From the page:
"Researchers have confirmed the existence of a SECOND Earth located in
the Proxima Centauri System. The planet is believed to have oceans just
like Earth and may hay host alien life.
In the past, thousands of exoplanets have been discovered in the
universe, but none of them is like Proxima B."

The opening paragraphs are over-hyped (later, the article says, "*If*
the planet proves to be a SECOND Earth ..."), but it still looks like a
good excuse to start an interstellar space mission.

--
Mark Isaak eciton (at) curioustaxonomy (dot) net
"Omnia disce. Videbis postea nihil esse superfluum."
- Hugh of St. Victor

[Andre G. Isaak]

In article <pphe6p$sp8$1...@dont-email.me>,

Mark Isaak <eciton@curiousta/xyz/xonomy.net> wrote:

> Good news for panspermists and future space travelers. An earth-like
> planet has been found around Proxima Centauri.
>
> http://www.thescinewsreporter.com/2018/10/its-official-researchers-have.html
>
> From the page:
> "Researchers have confirmed the existence of a SECOND Earth located in
> the Proxima Centauri System. The planet is believed to have oceans just
> like Earth and may hay host alien life.
> In the past, thousands of exoplanets have been discovered in the
> universe, but none of them is like Proxima B."
>
> The opening paragraphs are over-hyped (later, the article says, "*If*
> the planet proves to be a SECOND Earth ..."), but it still looks like a
> good excuse to start an interstellar space mission.

The wikipedia article on this planet states it has an orbital period of
11.2 days. I'm not an astrophysicist, but to me that suggests its
rotational period is likely tidally locked, which means it's probably
not all that habitable.

Still, an interstellar mission always sounds fun... They could divert
all that wall funding to it.

Andre

--
To email remove 'invalid' & replace 'gm' with well known Google mail service.

[jillery]

Stephen Baxter wrote a book "Proxima" where Proxima b was an important
plot point. Although the planet's existence was confirmed in 2016, it
was first noted in 2013, which is the same year as the book's
copyright. It's a good read, although I thought the strategy for
colonizing Proxima b to be self-contradictory. I can't say more
without posting plot spoilers.

The planet's climate depends on several factors which haven't been
determined with certainty at this time. For example, although we know
it's minimum mass is 1.25 times that of Earth, it may actually be
several times as massive. For example, its rotation can only be
inferred based on its closeness to Proxima. Depending on its orbital
eccentricity, it may have a resonance of 1:1 or 3:2 or 2:1. For
example, it may have a thick atmosphere like Venus, or hardly any like
Mars. All these factors have huge impacts on the planet's global
climate.

My impression is the fact that Proxima is an energetic flare star is
the largest challenge to indigenous life on Proxima b.

--
I disapprove of what you say, but I will defend to the death your right to say it.

Evelyn Beatrice Hall
Attributed to Voltaire

[Oxyaena]

It's still possible for life to exist on *Proxima Centauri b*, a planet
I've discussed before, even though the chance is remote. It really
depends on several factors such as the density of the atmosphere of
*Proxima b*, whether or not it has a magnetic field, and of course the
terminus zone, the region on a tidally locked planet where it is
perpetually twilight (the terminus zone occurs anywhere where twilight
exists, but only for short periods of time on Earth because the Earth
isn't tidally locked), and where conditions are potentially mild enough
for liquid water to exist, although even in the terminus zone conditions
would still be hellish from an earthly point of view.

[jillery]

...assuming Proxima b is tidally locked 1:1...

>where it is
>perpetually twilight (the terminus zone occurs anywhere where twilight
>exists, but only for short periods of time on Earth because the Earth
>isn't tidally locked), and where conditions are potentially mild enough
>for liquid water to exist, although even in the terminus zone conditions
>would still be hellish from an earthly point of view.

Correct. The problem is evidence for these factors can't be detected
at this time. The James Webb Space Telescope will change that, if it
ever gets launched.

[jonathan]

On 10/9/2018 1:26 AM, Mark Isaak wrote:
> Good news for panspermists and future space travelers.  An earth-like
> planet has been found around Proxima Centauri.
>
> http://www.thescinewsreporter.com/2018/10/its-official-researchers-have.html
>
>
> From the page:
> "Researchers have confirmed the existence of a SECOND Earth located in
> the Proxima Centauri System. The planet is believed to have oceans just
> like Earth and may hay host alien life.
>   In the past, thousands of exoplanets have been discovered in the
> universe, but none of them is like Proxima B."
>
> The opening paragraphs are over-hyped (later, the article says, "*If*
> the planet proves to be a SECOND Earth ..."), but it still looks like a
> good excuse to start an interstellar space mission.
>

Until the James Webb launches and we can analyze
the light from exoplanets such announcements about
habitability are wildly speculative. It's as likely
to be a rock as habitable.

https://www.jwst.nasa.gov/

It launches in 2021 and should be a quantum leap
in the search for life elsewhere. And btw I'm
convinced the universe is teeming with life, it
must be so, considering that the ideal initial
conditions for self organization is merely chaos.

Or, once the Second law has done it's job well
the ideal conditions for spontaneous cyclic order
has been created.

Whether a massive cloud of gas and dust, zero order
or chaos, that has been disturbed.

Or the infamous primordial soup given a jolt or three.

A persistent energy gradient, standing poised
at the transition state between it's opposites
in possibility.

For instance, at a higher level the jumbling of facts
and imagination, it's opposite in possibilities, leading
suddenly to a novel idea.

Or a system where laws and freedom, it's opposites, are
critically interacting creating a stable, evolving
democracy.

Or a system where genetics (rules) and selection (freedom)
critically interact creating Darwinism.

And so on.

Just picture a pedestrian cloud, standing poised
at the transition between it's opposites in
possibility, water and vapor, spontaneously
creating emergent phenomena such as rain, lightning
and vortexes.

The universe is simple, all that exists can be explained
by the logical relationship seen in any passing cloud.

And life is just as inevitable.


Jonathan


s




--

[Oxyaena]

Here's to hoping.

[satoshi]

On Monday, October 8, 2018 at 11:45:03 PM UTC-7, Andre G. Isaak wrote:
> In article <pphe6p$sp8$1...@dont-email.me>,
> Mark Isaak <eciton@curiousta/xyz/xonomy.net> wrote:
>
> > Good news for panspermists and future space travelers. An earth-like
> > planet has been found around Proxima Centauri.
> >
> > http://www.thescinewsreporter.com/2018/10/its-official-researchers-have.html
> >
> > From the page:
> > "Researchers have confirmed the existence of a SECOND Earth located in
> > the Proxima Centauri System. The planet is believed to have oceans just
> > like Earth and may hay host alien life.
> > In the past, thousands of exoplanets have been discovered in the
> > universe, but none of them is like Proxima B."
> >
> > The opening paragraphs are over-hyped (later, the article says, "*If*
> > the planet proves to be a SECOND Earth ..."), but it still looks like a
> > good excuse to start an interstellar space mission.
>
> The wikipedia article on this planet states it has an orbital period of
> 11.2 days. I'm not an astrophysicist, but to me that suggests its
> rotational period is likely tidally locked, which means it's probably
> not all that habitable.

Explain why you think tidal lock factors into habitability

[jillery]

GIYF

[Andre G. Isaak]

In article <bf0c9855-35ae-45a0...@googlegroups.com>,

I would think that should be rather self-explanatory. Do you think the
earth would continue to be habitable if it were tidally locked?

[Oxyaena]

It depends, for it is theoretically possible for a planet to be both
tidally locked and still be habitable. It depends on a number of
factors, including the density of the atmosphere (ie, if it can retain
liquid water), and of course the terminus zone, a region of the planet
that is in perpetual twilight, and would be potentially mild enough for
liquid water to exist. The conditions in the terminator zone would still
be hellish by earthly standards, IMHO.

[jillery]

As pointed out elsetopic, there are different resonances that can
occur with tidal-locking, depending on the eccentricity of its orbit.
You speak as if 1:1 is the only way. Mercury is tidally locked 3:2,
three rotations for every two revolutions.

[satoshi]

That your brain is locked?

[jonathan]

If you thought Hubble was a complicated project, look
at this deployment animation of the Webb, it'll take
a month to deploy and reach start it's halo orbit
around the L2 point. If they pull it off it'll
be quite an accomplishment.

James Webb Space Telescope Deployment In Detail
https://www.youtube.com/watch?v=bTxLAGchWnA


And the results could be breathtaking, from
the NASA page


Webb And Exoplanets

One of the main uses of the James Webb Space Telescope will be to study
the atmospheres of exoplanets, to search for the building blocks of life
elsewhere in the universe. But Webb is an infrared telescope. How is
this good for studying exoplanets?

One method Webb will use for studying exoplanets is the transit method,
which means it will look for dimming of the light from a star as its
planet passes between us and the star. (Astronomers call this a
"transit".) Collaboration with ground-based telescopes can help us
measure the mass of the planets, via the radial velocity technique
(i.e., measuring the stellar wobble produced by the gravitational tug of
a planet), and then Webb will do spectroscopy of the planet's atmosphere.

Webb will also carry coronagraphs to enable direct imaging of exoplanets
near bright stars. The image of an exoplanet would just be a spot, not a
grand panorama, but by studying that spot, we can learn a great deal
about it. That includes its color, differences between winter and
summer, vegetation, rotation, weather...How is this done? The answer
again is spectroscopy.

+ Sodium in atmosphere of exoplanet HD 209458

The presence of sodium in the atmosphere of Hot Jupiter exoplanet HD
209458 is measured by studying its spectrum. Credit: A. Field, STScI

Spectroscopy

Spectroscopy is simply the science of measuring the intensity of light
at different wavelengths. The graphical representations of these
measurements are called spectra, and they are the key to unlocking the
composition of exoplanet atmospheres.

When a planet passes in front of a star, the starlight passes through
the planet's atmosphere. If, for example, the planet has sodium in its
atmosphere, the spectrum of the star, added to that of the planet, will
have what we call an "absorption line" in the place in the spectra where
would expect to see sodium (see graphic below). This is because
different elements and molecules absorb light at characteristic
energies; and this is how we know where in a spectrum we might expect to
see the signature of sodium (or methane or water) if it is present.

Why is an infrared telescope key to characterizing the atmospheres of
these exoplanets? The benefit of making infrared observations is that it
is at infrared wavelengths that molecules in the atmospheres of
exoplanets have the largest number of spectral features. The ultimate
goal, of course, is to find a planet with a similar atmosphere to that
of Earth.
https://jwst.nasa.gov/origins.html

> --
> I disapprove of what you say, but I will defend to the death your right to say it.
>
> Evelyn Beatrice Hall
> Attributed to Voltaire
>

--

[jonathan]

Life is highly cyclic in character.


As Emily said so well.



"When I have seen the Sun emerge
From His amazing House --
And leave a Day at every Door
A Deed, in every place --

Without the incident of Fame
Or accident of Noise --
The Earth has seemed to me a Drum,
Pursued of little Boys"




s

>
>> Andre
>>
>> --
>> To email remove 'invalid' & replace 'gm' with well known Google mail service.
>

--

[Bob Casanova]

On Sat, 13 Oct 2018 09:20:07 -0700 (PDT), the following
appeared in talk.origins, posted by satoshi
<travellin...@gmail.com>:

So, from the multiple responses which gave at least *hints*
to the answer, you chose to post an insult to this single
one?

If you knew *anything* about the subject you should indeed
be able to understand why tidal locking is a potential issue
for habitability.
--

Bob C.

"The most exciting phrase to hear in science,
the one that heralds new discoveries, is not
'Eureka!' but 'That's funny...'"

- Isaac Asimov

[satoshi]

Only to someone who is a complete idiot

[Bob Casanova]

On Sat, 13 Oct 2018 11:56:25 -0700 (PDT), the following

>Only to someone who is a complete idiot

So only a complete idiot can understand? I tend to disagree,
but if you're correct you should have no problem
understanding.
--

[Pro Plyd]

That old tv series Lost in Space was somewhat prescient!