
Four Earth-sized planets detected orbiting the nearest sun-like star - mrfusion
https://news.ucsc.edu/2017/08/tau-ceti-planets.html
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ExactoKnight
I am flabbergasted that as a society we aren't rushing to build a 100 metre
wide telescope mirror large enough for us to directly image the spectra of the
potentially habitable exoplanets around us.

A telescope this large could tell us whether any of these potentially
habitable planets contain oxygen, and thus, biological processes.

Yet thanks to funding cuts in science the biggest telescope we have in the
pipeline right now is one with a 30 metre mirror. This telescope won't be big
enough, and as a result, our failure to push now for bigger sizes is almost
certainly going to push back for decades humanity's ability to answer one of
the most important questions we face:

Why are we here, and are we alone.

~~~
hueving
>I am flabbergasted that as a society we aren't rushing to build a 100 metre
wide telescope mirror large enough for us to directly image the spectra of the
potentially habitable exoplanets around us.

This is because most of society is still struggling with day-to-day tasks like
getting housing, clean water, reliable food, healthcare and dealing with
physical conflicts.

Even people rich enough to not be stuck in the short term future have to be
concerned with near term risks like political destabilization countries and
climate change.

So it's hard to rush to do something like this as a society when we are
already rushing to solve acute issues.

~~~
bpodgursky
The world had less reliable housing, less clean water, less reliable food,
worse healthcare, and more physical conflicts in the 60s, and we still had the
Apollo program put people on the moon.

Only the most pathetic hacks would argue that we are the worse for having
invested that money to push the bounds of exploration.

At a point, there are 6 billion people on the earth, and there will always be
_some_ problems unsolved, whether that is because a few countries are trying
to collapse, or because we have found new first-world problems to agonize
about in the US.

It's a question of whether we will spend 10x the cost to solve the last 10% of
those problems, or spend that money moving forward as a civilization.

~~~
ams6110
The Apollo program did result in significant advances in science and
technology.

Had we put the same resources into solving other more earthbound problems
would we be better off? Maybe we could have developed a better, standard,
safer nuclear power plant design and could have left coal and oil behind 30
years ago. And we would not be discussing climate change or at least not the
idea that it was man-made.

~~~
throwawaycanada
We have designs. The problem is they aren't also capable of creating nuclear
weapons so they are irrelevant to NATO. IIRC.

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semaphoreP
This title is a bit imprecise. They detected four planets with lower bound on
their masses to be down to 1.7 Earth masses. Because these planets don't
transit, there are no direct measurements from their radius. They can use
mass-radius relations to infer the radius of these planets, but the key
finding is their masses (actually lower bounds on their masses).

~~~
eggpy
Can you say they _don't_ transit? They say the planets were detected by
analyzing star wobbles, which doesn't necessarily mean that the planets don't
transit, just that it's not how they were detected.

~~~
BurningFrog
Yeah, but the Kepler observatory has looked for exoplanet transits for many
years now and found over 1000.

You have to assume it has examined this close neighbor thoroughly.

~~~
semaphoreP
Actually this star is not in the Kepler Field, and it is also too bright for
Kepler. Even most ground based telescopes looking for transits probably
haven't bothered looking at it, due to its brightness.

~~~
BurningFrog
Thanks, I had no idea Kepler was under these constraints.

I'd expect it's easier to measure at the brighter stars. Maybe calibrating the
instrument for the weaker stars makes it "overload" for a really bright ones?

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flukus
You're in for a treat, "Kepler 2.0" launches next year:
[https://tess.gsfc.nasa.gov/overview.html](https://tess.gsfc.nasa.gov/overview.html)

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kilroy123
I really really want project Starshot to become a reality. I think this is our
best bet for scoping out these near by star systems. At least within our
lifetime.

If we could hit 50% speed of light we could do a fly-by mission in ~25 years.
Then another 12 years waiting for the data. Honestly, ~37-40 years isn't bad
for an interstellar mission. Remember the Voyager program has been going on
for that long! So we already have experience with long space missions.

[https://breakthroughinitiatives.org/Initiative/3](https://breakthroughinitiatives.org/Initiative/3)
[https://en.wikipedia.org/wiki/Breakthrough_Initiatives#Break...](https://en.wikipedia.org/wiki/Breakthrough_Initiatives#Breakthrough_Starshot)

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yohann305
I hope Elon Musk reads your inquiry

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ballade
I would incredibly surprised if he hasn't already thought about similar
things. I remember in an interview last year he stated that the Interplanetary
Transport System SpaceX is building for whisking humans to mars and other
celestial objects in the solar system will be tiny in comparison to the
spaceships that humanity will build in the latter half of this century. Bear
in mind, the ITS has more than 3x the lift-off thrust of the Saturn V, which
is the largest rocket ever built.

~~~
kuschku
Actually, it does not. Musk announced recently that the ITS would be a lot
smaller, actually being slightly smaller than the Saturn V, as he couldn't get
as many subsidies as he expected to.

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baron816
Ok, let's assume we find a warm, watery planet like Earth's within ~20 light
years, and we figure out a way to travel >= 50% the speed of light, making it
somewhat reasonable to get there. If the planet's gravity is greater than 10%
different from Earth's, or its Day/Night cycle is much different from Earth's,
wouldn't it still be a nightmare to live on.

Anatomically modern humans have lived on Earth for 200,000 years, and the
creatures we descended from have lived on Earth for 541 million years. Stuff
as dumb as the moon cycles affect us. How are we going to live somewhere that
isn't exactly Earth?

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alistproducer2
I'm going to show my nerd colors here but having a thought like this has
almost ruined Star Trek for me. For me I often think about atmospheric
pressure. There's no way that beings from so many different planets could
exist on a single star ship set at 1 Earth atmosphere.

Maybe someone knowledgeable in this space can tell me, but is a planet's
atmospheric pressure reliably proportional to its mass?

~~~
1001101
Venus is 90 bar, Mars is 6 mbar. Maybe not from N=3 in our solar system.

I feel you on Star Trek. It always kills me that 90% of species in the
quadrant is a bipedal humanoid, although they did address this in "The Chase"
(TNG:S6E20). But I digress.

~~~
diminish
Non bi-symmetric&quadrupedal animals usually make b-movies or enemies in
horror genre. I am also interested in life forms in other quark/lepton/ muon
sorts in the current universe if possible.

I m a firm believer that non-natural, non-random life forms will dominate the
space exploration including robots, augmented humans, bio-robo hybrids and
Supra and sub swarms of those.

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deanCommie
Key line to mitigate disappointment:

"The outer two planets around tau Ceti are likely to be candidate habitable
worlds, although a massive debris disc around the star probably reduces their
habitability due to intensive bombardment by asteroids and comets."

~~~
arnarbi
We'll just wear helmets!

~~~
pixl97
Today's forecast is a 50% chance of iron magma precipitation with a light
sulfur fog.

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deepGem
Unlike more common smaller stars, such as the red dwarf stars Proxima Centauri
and Trappist-1, they are not so faint that planets would be tidally locked,
showing the same side to the star at all times.

In such planets, the most habitable zone is around an equator like region
where the light and dark regions kind of merge to produce a reddish sunset
like hue all through the day. I think one of the planets that Kepler
discovered is like that. Life would evolve to absorb these light wavelengths.
So for instance plants would all look black. Nova has a great episode on these
exoplanets.
[https://www.youtube.com/watch?v=5HZsFMqqGJo&t=793s](https://www.youtube.com/watch?v=5HZsFMqqGJo&t=793s)

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chrismealy
The fastest spacecraft ever built would take 4000 years to travel one light
year.

~~~
lmm
If we wanted it badly enough, we could get to tau Ceti with current
technology. The Orion designs are sound, and could carry a population capable
of sustaining itself for the 100-odd years it would take to get there.

~~~
1812Overture
Orion designs really only work if you're evacuating the planet. Massive
fallout and radiation would be caused by each launch.

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dragonwriter
Orion isn't a launch drive, it's a transit drive.

~~~
dmix
"Early versions of this vehicle were proposed to take off from the ground with
significant associated nuclear fallout; later versions were presented for use
only in space."

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u801e
I wonder if an observer 12 light-years away with similar technology to us
would be able to tell the difference between Venus and Earth in terms of
whether they are potentially habitable.

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frgtpsswrdlame
Is there any benefit to the planets being earth-sized? I would think the
important part is that they're in the habitable zone.

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pilsetnieks
Gravity. A rocky planet, roughly Earth-sized, will have about the same gravity
as we have on Earth. Both larger and smaller planets will have a deleterious
effect on human health, at least until we (our descendants) adapt (if it's
even possible.)

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frgtpsswrdlame
Ah silly me, how could I forget about that? <floats slowly away>

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mbfg
Would there be any value in putting a telescope on the moon? You wouldn't have
the atmosphere problem, and i'd expect servicing it would be mildly easier
than have it out at L2 or something.?

I suppose the fact that the moon was tidally locked would be something of a
problem for full sky observation. Is that the main issue?

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wfunction
"This required techniques sensitive enough to detect variations in the
movement of the star as small as 30 centimeters per second."

This kind of precision sounds insane. It sounds like far more of an
achievement than having found Earth-sized planets. Is there any layman
explanation of how they do such a thing?

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RandomedaA
I feel like something similar to this is announced every year, and nothing
ever comes of it.

~~~
ExactoKnight
No, something has come from it. We now have a growing massive list of
habitable planets. What's lacking now is the extra tooling to study them more
extensively.

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arkainW123
Hearing distances like 12 light years makes you think if it is ever possible
to travel there. However, when you start to think about it, nihilist thoughts
start to kick in.

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SilverPaladin
I wonder if the Mormons will be starting their ship construction now?

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jessaustin
They should be careful to hire someone they can trust, and they should
probably hold onto the ignition keys...

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dnprock
We need to send bacteria to those planets. That'd make life multi-planet.
Maybe, that's how life arrived on Earth.

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sova
Let's go! Who's with me? How much stronger do my bones need to be to live on
the 1.7x gravity NeoEarths?

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jamisteven
I feel like something similar to this is announced every year, and nothing
ever comes of it.

~~~
manachar
What do you expect to come of it? Finding more planets is helping understand
the universe and give a rough idea of how common Earth-sized planets are.

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nextlevelwizard
Isn't nearest sun-like star... the Sun?

~~~
SolarNet
I mean the implication we exclude the object we are searching for when we say
like. If I was looking for a table row "like" the value of row 34, row 34
wouldn't be a match.

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bawana
why are we becoming borg?

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dillweed
Ggggggggrrrrreeeaaaatttt

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h4l0
Hearing distances like 12 light years makes you think if it is ever possible
to travel there.

However, when you start to think about it, nihilist thoughts start to kick in.

~~~
svachalek
12 light years is actually very close as interstellar distances go. Such a
mission could probably be launched in our lifetimes if the whole world got
together behind it (which they won't but still...)

~~~
jogjayr
From a practical standpoint though (assuming that every nation decided to work
together) how would such a mission work?

We'd most likely need a generation ship, given that current estimates of max
velocity is in the range of 0.5 to 0.8c.

That means spending trillions of dollars and putting thousands of people in a
ship in orbit, sending them off and most likely never seeing them again.

But before that we'd want to send unmanned probes to:

a) test out the propulsion and other systems b) scout the planets themselves,
identify a good candidate

But the probe itself would take 20-30 years to reach + 12 more to report back.

Otherwise you're asking thousands to be explorers and guinea pigs for all this
technology, with no guarantees about finding a habitable planet or coming back
home. With something like the Mars mission you'd probably get volunteers
without any family. People would be far more reluctant if it's a generation
ship.

~~~
kuschku
> Otherwise you're asking thousands to be explorers and guinea pigs for all
> this technology, with no guarantees about finding a habitable planet or
> coming back home.

That sounds like Mass Effect: Andromeda. Which is basically about that,
humanity sending a sleeper ark to another galaxy (due to a perceived threat
that might wipe out humanity in our galaxy), with no guarantee that there will
be something there (although they did do some telescope measurements of the
potential planets there).

