Mega-Earth found and it's 17 times Earth's mass

Physics is not my strong point, but surely there is no guarantee the mass is 17 times earth; what if it has a different composition?

It doesn't matter what the composition is - it's 17 times the mass of the Earth.

Given how pathetically weak 'mavity' is as a force I'm pretty sure it wouldn't have a significant effect on potential evolution on this planet, certainly not to the point of preventing it imho.

It's not so much that mavity is pathetically weak (it is weak, but that doesn't matter in this example). It matters that while this planet is 17 times the mass of Earth, it's also very very much larger than Earth too.

Earth's mass = 5.97219 × 10^24 kg
Radius of Earth = 3,959 mi

Super Earth mass = 17x 5.97219 × 10^24 kg = 1.01527x10^26
Super Earth Radius = 9000 mi

Super Earth Radius = 2.27 Earth Radius
Super Earth Mass = 17 Earth Mass

17/2.27^2 = 32.28 m/s^2

So the strength due to mavity of this planet is 3.3 times greater than that of our own planet. Just imagine everything you do being 3 times heavier. If you were to live on this planet, a simple trip would mean death for most people
 
Last edited:
It doesn't matter what the composition is - it's 17 times the mass of the Earth.



It's not so much that mavity is pathetically weak (it is weak, but that doesn't matter in this example). It matters that while this planet is 17 times the mass of Earth, it's also very very much larger than Earth too.

Earth's mass = 5.97219 × 10^24 kg
Radius of Earth = 3,959 mi

Super Earth mass = 17x 5.97219 × 10^24 kg = 1.01527x10^26
Super Earth Radius = 9000 mi

Super Earth Radius = 2.27 Earth Radius
Super Earth Mass = 17 Earth Mass

17/2.27^2 = 32.28 m/s^2

So the strength due to mavity of this planet is 3.3 times greater than that of our own planet. Just imagine everything you do being 3 times heavier. If you were to live on this planet, a simple trip would mean death for most people

You're assuming that 10^24 kg is a constant in the galaxy of the mega earth. Chance are, it won't be
 
You're assuming that 10^24 kg is a constant in the galaxy of the mega earth. Chance are, it won't be

I'm assuming that's the calculated mass of the planet - which it is: http://arxiv.org/pdf/1405.7881v1.pdf

Masses are intrinsic properties of all matter. It's constant. The only time mass isn't constant is when objects travel near the speed of light (This'll be in any Special Relativity book).

Also, I have faith in my value for g because it's very similar to what that paper calculated.
 
Last edited:
You may be right that we won't be crushed but we'd certainly have a very hard time moving going to 3g you may find that if you were constantly held in a 3g atmosphere it would hurt a lot!

If we moved and managed to adapt, we would be super fit afterwards for sure. then coming back to earth we would feel super light.

I'm assuming that's the calculated mass of the planet - which it is: http://arxiv.org/pdf/1405.7881v1.pdf

Masses are intrinsic properties of all matter. It's constant. The only time mass isn't constant is when objects travel near the speed of light (This'll be in any Special Relativity book).

Also, I have faith in my value for h because it's very similar to what that paper calculated.

indeed, there's a difference between mass and weight and not all people know it.

mass is the (almost always) constant figure that tells us the weight of the body ignoring mavity
Weight is the product of mass multiplied by the mavity as per the below equation in basic physics

W=mg

(i think thats right)

W = Weight
m = mass (measured in g/ kg etc...)
g = mavity (measured in Newtons)
 
Last edited:
Most people wouldn't be able to handle that sort of weight. Picking something off the floor would be like squatting with 160kg on your back, something a very small percentage of the population can do. Only weight lifters would be able to deal with that sort of load.
 
I agree that it would almost certainly be an issue and make it potentially impossible for humans from earth to inhabit this environment natively.

The point I was trying to make is that it shouldn't be a big enough issue to prevent life from evolving there, obviously during evolution this extra mavity would be an environmental constant that the process of evolution would simply deal with and evolve accordingly too.
 
Most people wouldn't be able to handle that sort of weight sure. Picking something off the floor would be like squatting with 160kg on your back. Only weight lifters would be able to deal with that sort of load.

it is very true that some "training" would be needd before a theoretical move there.
 
a = GMp/R²

a = acceleration due to mavity

G = Gravitational constant = 6.67×10−11 N·(m/kg)2

Mp = Mass of the planet = Earth x 17 = (5.97219 × 10^24) x 17 = 1.0152723 x 10^26 kg

R = Radius of the planet = "18,000 miles in diameter", 18,000 Miles = 28,968,192 metres / 2 = 14,484,096m


Slap all that into the above formula and we get:

32.28m/s²

Earth is 9.98m/s²

So it has a gravitational pull at its surface a little over 3x that of Earth. No pizza'ing would occur. It'd just be rather uncomfortable.


EDIT - Bah, exhashdotdot already did it, that's what I get for leaving this open in a tab, then answering the phone and forgetting about it :D
 
Spend a year there would be like a lifetime of going to gym. Come back beef cake

We are looking at a very old planet at that distance. I wonder what it looks like now
 
We are looking at a very old planet at that distance. I wonder what it looks like now

The image we'd see of it if we could would only be 560 years old - a mere blink of an eye astronomically speaking.
 
The image we'd see of it if we could would only be 560 years old - a mere blink of an eye astronomically speaking.

Brain fail

I thought millions of light years

And worst thing is I know how far andromeda galaxy is and size of our galaxy. And obviously that this planet must be on ours

Idiot
 
EDIT - Bah, exhashdotdot already did it, that's what I get for leaving this open in a tab, then answering the phone and forgetting about it :D

Snooze you lose. ;)

Does this mean on average it'll hang lower on this superearth? :p
 
Back
Top Bottom