They need better names for these planets now that they know for sure they exist. I know they can do better than GJ667Cc.

Aborted Baby Jesus Fetus: They need better names for these planets now that they know for sure they exist. I know they can do better than GJ667Cc.

Agreed. What are we supposed to call the inhabitants? GJ667Cc-lings?

Well wouldnt the gravity on this super earth crush our tiny little bodies anyways? Couldnt RTFA wouldnt load.

groppet: Well wouldnt the gravity on this super earth crush our tiny little bodies anyways? Couldnt RTFA wouldnt load.


I'm guessing that it would be too high of gravity to be comfortable or practical for us, but the main point of TFA was that these planets that we once thought would be exotic seem to be freakin' everywhere. And this one is - by cosmic standards - right next door. This one may be massive for us, but it's a rocky planet in the habitable zone orbiting a star in a trinary cluster - and it's a cluster of stars which don't seem to have the elements necessary to form a planet like this. And if there is life there, that revelation alone would be worth the find, even if we couldn't colonize the planet. It might suggest that there are tons of habitable planets scattered about the cosmos, and if life is on it it might also suggest that there are lots of planets around the cosmos on which there is life of some kind.

Any physicists who could hazard an estimate on what the gravity on the surface would be? They said that it has 4.5 times the mass of Earth, but I guess you'd need to know the actual size as well. I'd think the gravity on the surface would probably be like 4x Earth gravity or so, but that's just me tossing a wild guess out there.

They should start with Alderaan and work down the list Planet Names (new window)

Super Earth is a stupid name, let's name it "Trantor".

mongbiohazard: Any physicists who could hazard an estimate on what the gravity on the surface would be? They said that it has 4.5 times the mass of Earth, but I guess you'd need to know the actual size as well. I'd think the gravity on the surface would probably be like 4x Earth gravity or so, but that's just me tossing a wild guess out there.

IANAP, but it is completely dependent upon the size. 4X gravity would require the planet to have close to the same diameter as earth, making it very dense. If it is 4X diameter as well as mass, then gravity would be a lot closer to 1g.

Oh, and in reality it's probably somewhere in between those extremes, say 2.5-3g.

What about a ring world? Couldn't we just flatten the material in the earth and build a ring about 1 mi deep at approximately 1 AU out, how wide would it be?

Assuming that the density of "Super Earth" is the same as earth:

Gravitaional acceleration is given by a = GM/r² where G = G = 6.6726 x 10-11N-m2/kg2

We need the mass of Super Earth, which is minimally 4.5xM_e
We need the radius of Super Earth, which can be calculated:

M_e = 5.9736×1024 kg
r_e = 6,371.0 km

density = mass/volume, so if the mass goes up by 4.5, so does the volume.
and V(sphere) = 4/3(pi*r³)

So, r_se = (4.5V_e/((4/3)*pi))^1/3 = 10,518 at the surface

The mass of SE is 4.5*M_e = 2.6881x10²⁵

Therefore, gravitational acceleration at the surface, g, should be about 16.2134m/s², which is a little under twice what it is for earth - 9.8m/s².

Since weight is mass*g, if you weigh 200lbs here on earth, you would weigh 200 * (g_se/g_e) ~ 330lbs

//not responsible for shoddy work

Mayhem of the Black Underclass: What about a ring world? Couldn't we just flatten the material in the earth and build a ring about 1 mi deep at approximately 1 AU out, how wide would it be?

Ok, so I fail at math, but the volume of the earth is 1,083,210,000,000 km^3, and the circumference of a circle 1AU out is 939,951,956 km. So how wide would that be?

This is farking cool as hell. Both because we could have a radio chat with any radio-capable life within 50 years, AND because we could bring frickin' alien planet rocks back in 400 years... AND because we could go, as the scientist said, take pictures and beam them home in 250... AND for all the other planets like it which we'll find in less than five years.

Cooooool as balls.

Is it simply 1,083,210,000,000km^3 / 939,951,956km / 939,951,956km = .000001226km wide?

Grither: Is it simply 1,083,210,000,000km^3 / 939,951,956km / 939,951,956km = .000001226km wide?

What exactly are you calculating that's so small? I don't get it.

Volume of the Earth = 1,083,210,000,000 km³
What width could we achieve if the Ring was 1km deep?
1AU = 149,598,000km

Create a solid of πr²h, where r is 1AU, remove from the middle a cylinder with r of 1AU - 1km.
Volume of the Earth = πr₁²h - πr₂²h
V_E = (πr₁² - πr₂²)h
V_E / (πr₁² - πr₂²) = h
1,083,210,000,000 km³ / (π* 22,379,561,604,000,000 km² - π* 22,379,561,304,804,000km²) = h
1,083,210,000,000 km³ / (70,307,466,325,686,600km² - 70,307,465,385,734,600km²) = h
1,083,210,000,000 km³ / (939,951,960km²) = h
1,152.41km=h

The width of the ringworld made using only the Earth would be 1,150 kilometers if the ring world was 1 kilometer thick.

If we crushed the earth into a flat ring 1km deep to ring the circumference of it's orbit, I think it would be .000001226km wide. But I am bad at math, so I could be wrong.

I think you've got your units wrong, Mayhem. Isn't circumference in km, not in km^2?

I think it's because you have pi*r^2, which is volume, not circumference. circumference is pi*2r, or pi*d.

aerojockey: Tidally locked, so probably lacks an atmophere.

Venus is nearly tidally locked and it has all kinds of atmosphere.


I dont think there is currently a consensus on the habitability of tidally locked planets.

Grither: I think it's because you have pi*r^2, which is volume, not circumference. circumference is pi*2r, or pi*d.

His approach is okay. He's taking the volume of a cylinder with radius rougly equal to Earth's orbit, and removing from it the center of it another cylinder with a volume equal to the radius of earth's orbit minus 1 km. This effectively gives you the volume of a ring 1km thick. Doing so allows you to create a ring some 1000 km tall. I didn't run the numbers, but this approach is valid.

What you've done is taken the Earth's volume and converted it from a sphere to a box some 900 million km long , 900 million km wide, and veeeery very short. This box has a large surface area. Jupiter could roll around on top of it as it orbits the sun.

Flt209er: and removing from it the center of it

Extra "it"s included free of charge.

RoxtarRyan: ronin7: aerojockey: Tidally locked, so probably lacks an atmophere.

Venus is nearly tidally locked and it has all kinds of atmosphere.


I dont think there is currently a consensus on the habitability of tidally locked planets.

Depending on the conditions, it can have two extremes of weather (one hot, one cold), perhaps mitigated by atmospheric phenomenon, but that would make for some severe freakin' upper atmosphere level winds to have a chance of somewhat leveling out the temperature. Also, because the lack of sunlight on one side, expect the hypothetical life forms to be a bit different from one side to the next, from their senses (no point in having sight if there is nothing to see), to temperature tolerance, etc.

Eh, but I'm no scientist. Just a dude who watches too much science fiction.

Yeah, just not sure where the no atmosphere thing comes from. But like you I am no scientist so maybe I am missing something.

Its just big boned.

Super Earth with triple stars? I'd be stupid NOT to go there.

FTA: It was big news when just one was announced back in September; we've already got several more examples in hand. In short, the unexpected is something planet hunters have learned to expect - and in most cases, these surprises have tended to expand the possibilities for finding worlds where life might thrive.



The Universe is kinda big.

Aborted Baby Jesus Fetus: They need better names for these planets now that they know for sure they exist. I know they can do better than GJ667Cc.

well, if it works like anywhere else, whatever they call themselves.

Mayhem of the Black Underclass: What about a ring world? Couldn't we just flatten the material in the earth and build a ring about 1 mi deep at approximately 1 AU out, how wide would it be?

A Ringworld is unstable in the plane, and a Dyson world is unstable in any axis.

It's basically the same proof that you use to prove that there isn't any net gravitic acceleration inside a hollow sphere from the sphere itself.

PsychoChimp: density = mass/volume, so if the mass goes up by 4.5, so does the volume.
and V(sphere) = 4/3(pi*r3)

But doesn't that assume it's made of the same stuff as earth, in roughly the same proportions? Mass is mass, whether it's plutonium or helium.

TFA says, "but the stars in this system have surprisingly low levels of the heavy elements planets are made from."

Which I assume are things like iron and nickel, as well as denser stuff like lead, cadmium, uranium, gold, silver...which are pretty common on earth. Iron is needed for a magnetic field...right? There aren't any lighter elements that would be magnetic at high temperatures and pressures in a planetary core?

So, if its solid bits are made of only lighter stuff, like beryllium, lithium, magnesium, and maybe a little bit of iron at the core...could it support life? Would it maybe be very large in diameter, and maybe have gravity closer to 1g?

I'm going to be lazy...someone tell me how large would it have to be to have gravity of 1g, assuming it's, say, 1/3 as dense as the earth?

earthwirm: One thing I never got about BSG is why, after the discovered that Earth was a cinder why did they not go back to Kobol?

Well, it would have been a cinder after a couple generations too. It all happened before, and it would happen again.

But New Caprica...that seemed very habitable. I never got why they settled on some stupid sandy river delta that was obviously prone to flooding and not well suited to cultivation.

earthwirm: One thing I never got about BSG is why, after the discovered that Earth was a cinder why did they not go back to Kobol?


Don't you mean Kolob?

Oh wait, that's the Mormons.

Or was BSG based on Mormon fantasy?

erewhon: Mayhem of the Black Underclass: What about a ring world? Couldn't we just flatten the material in the earth and build a ring about 1 mi deep at approximately 1 AU out, how wide would it be?

A Ringworld is unstable in the plane, and a Dyson world is unstable in any axis.

It's basically the same proof that you use to prove that there isn't any net gravitic acceleration inside a hollow sphere from the sphere itself.

That's why you install jets around the rim

but hopefully before someone crashlands into the ring creating a new puncture

Stabone33: PsychoChimp: density = mass/volume, so if the mass goes up by 4.5, so does the volume.
and V(sphere) = 4/3(pi*r3)

But doesn't that assume it's made of the same stuff as earth, in roughly the same proportions? Mass is mass, whether it's plutonium or helium.

TFA says, "but the stars in this system have surprisingly low levels of the heavy elements planets are made from."

Which I assume are things like iron and nickel, as well as denser stuff like lead, cadmium, uranium, gold, silver...which are pretty common on earth. Iron is needed for a magnetic field...right? There aren't any lighter elements that would be magnetic at high temperatures and pressures in a planetary core?

So, if its solid bits are made of only lighter stuff, like beryllium, lithium, magnesium, and maybe a little bit of iron at the core...could it support life? Would it maybe be very large in diameter, and maybe have gravity closer to 1g?

I'm going to be lazy...someone tell me how large would it have to be to have gravity of 1g, assuming it's, say, 1/3 as dense as the earth?

Tfa says "earthlike rock" which is strange since the stars are light on heavier elements. Thus the density assumption.

d=m/v, so add a 1/3 in front of the d and rework the math above. d=3(4.5)m/v

1/3 density will bring down the gravity closer to 1g because r goes up.

//lazy too.
///toddler on lap prevents any meaningful work.

Yeah, just not sure where the no atmosphere thing comes from. But like you I am no scientist so maybe I am missing something.

Magnetic field and gravity both play a big role in why atmospheres stay on a planet.

I don't think anyone knows for sure, but some think is that an atmosphere on a tidally-locked planet is too unstable to survive: on the cold side the atmosphere could condense; on the hot side it could drift off fast.

The permanently cool side would cause a temperature/pressure gradient that would result in high winds, which in turn would convect heat to the cool side. Horizontal motion is easy for atmospheres, vertical motion is very difficult.There are a number of radiative transfer generated barriers to vertical motion in our own atmosphere (the stratosphere has a heat inversion - cold air rises and warm sinks) and I have no doubt that there will be some on other worlds too.

I'm going to be lazy...someone tell me how large would it have to be to have gravity of 1g, assuming it's, say, 1/3 as dense as the earth?

F=Gm₁M₂/r², so for the force of gravity to be the same:

G m_youM_earth/r_earth² = G m_you(4.5)M_earth/r_planet²

Cancel the G, m_you and M_earth so we get:

1/r_earth²=4.5/r_planet²

flip both sides and multiply by 4.5

r_planet² = 4.5 * r_earth²

Take sqrt:

r_planet = 2.12 r_earth

so the radius of the planet needs to be twice that of earth to have the same gravity - possible

Aborted Baby Jesus Fetus: They need better names for these planets now that they know for sure they exist. I know they can do better than GJ667Cc.

Maybe something starting with P8X?

In all seriousness, the wild speculation of these articles is pretty ridiculous. All they have is a semi-regular change in the received EM output of a star which leads them to think something is orbiting it. That's it. Everything else is pure guessing. And from there, news sites turn it into "A planet JUST LIKE EARTH has been found!!". The scientists don't actually know these are even planets, much less what they're made of, how big they are, what the temp is, etc. All guesses.

loonatic112358:

That's why you install jets around the rim

but hopefully before someone crashlands into the ring creating a new puncture

Biggest Gyroscope EVER

NotARocketScientist: so the radius of the planet needs to be twice that of earth to have the same gravity - possible

hm....cool.


OK...next question - might be a stupid one, but bear with me: What's the "average" composition of the earth? In other words, one should be able to calculate about where the "element" of the earth would fall on the periodic table by calculating the atomic weight of the "average" element based on earth's mass, density, and volume; then comparing that to the closest corresponding element in the periodic table.

Then...could we look at the mass of the super-earth, and put an upper bound on its "comfortable" gravity (say, 1.5g) and then calculate back to its "average" element? Would that be useful?

/I promise, I'm not writing a paper or anything.
//It's a nice day, and I just want to get outside and come back and find an answer.
///Lazy, too

The problem with finding planets like these is that while it's cool, it serves no purpose. The fastest thing in the universe - light photons - takes twenty-two years to get there from here.

This planet, with some basic math, is 9.46052841 × 10 to the 15th power miles away. There is virtually no way to get from where we are to where this planet is in a reasonable time span. The fastest man made spacecraft (New Horizons) is currently traveling at 0.0001% of the speed of light.

In short, unless we discover a way to exceed the speed of light safely, and then slow down, we will probably be forced to stick to the inner planets of the Solar system and Jupiter's moons.

Yaxe: The problem with finding planets like these is that while it's cool, it serves no purpose. The fastest thing in the universe - light photons - takes twenty-two years to get there from here.

This planet, with some basic math, is 9.46052841 × 10 to the 15th power miles away. There is virtually no way to get from where we are to where this planet is in a reasonable time span. The fastest man made spacecraft (New Horizons) is currently traveling at 0.0001% of the speed of light.

In short, unless we discover a way to exceed the speed of light safely, and then slow down, we will probably be forced to stick to the inner planets of the Solar system and Jupiter's moons.


Knowledge is its own end.

aerojockey: ronin7: Venus is nearly tidally locked and it has all kinds of atmosphere.

It's not even close to tidally locked on time scales it would take for an unbalanced atmosphere to drift off into space.

ronin7: Yeah, just not sure where the no atmosphere thing comes from. But like you I am no scientist so maybe I am missing something.

I don't think anyone knows for sure, but some think is that an atmosphere on a tidally-locked planet is too unstable to survive: on the cold side the atmosphere could condense; on the hot side it could drift off fast.

However one thing I didn't consider is that it's a triple star system, so maybe the other stars would mix things up in the atmosphere enough so that it's not so unbalanced.


Fair point on Venus, I guess when you consider the time scales it is spinning nicely.


Okay interesting though that its just not known. I guess that is all the more reason to learn more about this system.

Science is awesome.

MadSkillz: Amos Quito: earthwirm: One thing I never got about BSG is why, after the discovered that Earth was a cinder why did they not go back to Kobol?


Don't you mean Kolob?

Oh wait, that's the Mormons.

Or was BSG based on Mormon fantasy?

Yup. Glen Larson was a devout 'magic underwear' wearer.


That explains a lot, actually.

;-)

John Nash: Oh, and in reality it's probably somewhere in between those extremes, say 2.5-3g.

If it is composed of similar material to Earth, it will have a radius about twice that of Earth, and surface gravity of ~1.7g

Considering the low metalicity of the host star, and assuming that the planet formed in orbit of that star and wasn't a captured rogue planet, the planet is probably composed of lighter materials than Earth and therefore larger radius. It would conceivably have a surface gravity very close to that of Earth if it has a composition similar to the moon.