Anyone with good knowledge of physics/astrophysics?

[Ninajrr]

In response to:

Im sure there would be civilizations we havent discovered yet living on the other side of the planet if it was that big. That is a HUGE star.

Don't be so sure. Although the planet would be HUGE, our current technology would easily allow us to detect any radio signals or other kinds of EMR being broadcast on the other side of the "planet", which would clue us in to their existence. Also since we came about existence on this large planet, and have knowledge of our local solar system, I would presume scientists of that planet would expect there to be life coexisting on the other hemispheres, and would deliberately look for them as we look for life on nearby planets (Mars). The cool thing would be that the other "intelligent life" would be very un-human as I was going into earlier (physically). Its more likely they would be what we think of as "aliens", except local to our planet.

[kollos]

im guessing the planet would rotate very slowly, if at all, to make life possible. since the temperature on the day and night sides would be very different.
if there were lifeforms on both sides on the planet, they would probably never be able to meet. maybe those civilisations would be nomads, and at some point when the planet made half a turn they would reach ancient towns from the other civilisation that were living there thousands of years ago?

[TOOL]

Assuming that the only difference between this theoretical Superearth and Earth is the size, and all the other characteristics that make Earth unique and perfect for life as we know it (i.e. gravity, atmospheric pressure, temperature range, distribution of elements, magnetic field, etc...) are equal, I think the outcome would be that the biodiversity on the Superearth would be more or less proportional to its increased surface area.

There would be a wider variety environmental niches that would allow a larger number species to evolve to adapt to the local conditions, and a wider range of variations between similar species as well.

How this would influence intelligent life is of course more complicated, but would still be similar to what history has shown us here on Earth. Intelligent societies that developed near other intelligent societies would be more likely to be warlike than more isolated societies. But the competition for resources even between rival societies might not be as pressing of an issue as it has been on Earth, which would tend to decrease the number of wars.

Of course the warlike societies would be more likely to become more advanced more quickly, because nothing fuels innovation better than competition.

As with the lesser life forms, there would be more diversity present for longer periods of time before one species was able to spread out and dominate the majority of the planet. What we would call missing links between prehistoric primates and modern humans would probably still be present somewhere on Superearth.

This is a fun idea.

[Ionsniper]

Sure we would be able to make contact with other species once they achieve radio and laser communication of the sort but the probability of us meeting them anytime soon after contact is almost nil. Light takes 8 minutes to reach us from the sun. About half of what it takes to reach Jupiter maybe. Too lazy to look it up. Super earth reaches to at least Jupiter. So an hour and a half at the speed of light to reach other other side of the planet roughly. Could be longer since your traveling over the circumference and not in a straight line. So basically about an hour and a half at light speed to reach the other side. We dont have ANY technology to achieve anything close to that at our current technology. We still have problems just getting to the moon and Mars. The fastest plane we have I believe is the SR-71 Black bird and it does a trip from new York to LA in about an hour.

Right now our tech is not developed near enough to even meet life on the other side of the planet. Sure we can communicate with them but what good is that. Interesting to know theres someone else out there though. Maybe in another 100 years we will have to tech to visit them.

[Ninajrr]

No no, Ionsniper, you have it backwards! If we have the technology to communicate via radio transmission what do we need physical interaction for? Virtual communication is plenty, despite a 2 hour limbo period. Sure we can't touch them, but what good is that, at least we can communicate with them!

Also, comparing a trip to the Moon, or Mars, which is in empty space, is entirely different from a trip around a "SuperEarth", which happens to be surrounded by...well, not empty space! It takes about 6 months to send a satellite to Mars, but the problem we have with sending people is the resources (ie, there are none in space, so you gotta pack a lot of crap!). But that's not the case here, so it would actually be pretty darn easy, just take a bit of time!

Now, if the radius of this planet is 2000 times the radius of the Sun, which is 500,000 miles, then the length you'd have to travel to the opposite side is:

(2*pi*r)/2 = pi*1,000,000,000=3,140,000,000 miles.

Based on what you said, we can go around 3,140 mi/h. So, if we managed to use solar power to propel ourselves (or some other fuel with minimal refueling time) it would only take, roughly:

(3,140,000,000 mi) / (3,140 mi/h) = 1,000,000 hours, or ~115 years!

Is that a long time? Ehh, sort of, but its definitely not impossible!

What would be way easier (or cooler, at least) is if the SuperEarth had a nearby moon which we could get to and "ride" around the SuperEarth. Can only imagine the tidal waves a moon like that would produce...

[vurt]

If life (or more specifically, heredity) somehow managed to establish itself on this hypothetical planet, it'd evolve to best suit its environment. We have no real idea of how that evolution would transpire, but we can be sure that the organisms that best survived would propagate through their progeny, whatever they may look like.

Saying that the gravity would be too strong for things to move is silly; stuff would evolve to move on that planet. Maybe their legs would be a lot thicker, maybe they'd just be made of stuff that can cope with the stress, or maybe they wouldn't have legs at all -- who knows.

While we sure as heck don't know for sure that it's possible, we have no reason to be sure that life would be impossible either.

[Jimmy Carter wuwu]

Translated todays earth with the new earth we are speaking about. The fight over the gaza strip would be the size of 6 United States. What a cluster fuck that would be.

[Tuco]

Hey guys I think that the gravity on super earth would be too much for us to survive.

Assumptions:
1. As much of the land on super earth is as fertile as the land on earth
2. The days/night being several years long doesn't mess us up too badly because we get ultravision.
3. We have as much time as we want to to develop.

Predictions:
1. After becoming something resembling a human, during our hunter/gatherer stage of development we pretty much traverse the entire continent we are on, regardless of how big, before we end this stage. The reasoning is that I don't think we'll get out of our hunter/gatherer stage until population density is forced together to cause society/wars/growth etc. This would probably take several million years, maybe a billion.
2. After making primitive societies that don't move around (crops, husbandry etc), human development continues on with similar pace. Wars are less likely. However, it's likely that the land is indiverse, which means indiverse resources available.

[Ionsniper]

Well Ninajrr you have to consider the facts of the situation of our current technology. Sure its realistically possible, but logistically its not. Your not gonna have fueling stations on the trip over there. You also have to remember that things in space can travel alot faster than thru the atmosphere. So the best means to reach the people on the other side would be thru space travel. Right now our current technology limits us in visiting. Sure communication is good but you still got to deal with travel time and all that. Super Earth would have hundreds of civilizations living on it. Sure would be an interesting place.

[GaliemVaelant]

The gravity on the super planet would be too strong, Tuco is right. Whether life could ever form on such a planet is a question still very much in debate. What exactly are the generic qualifications for life to form on a planet? Is a planet even required? Right now, NASA is starting by checking what they call the "habitable zone" around stars -- the region where the temperature should be approximately close to that on Earth (right for water to exist in three states).

Essentially, human beings would not and could not exist on such a planet, but whether life could (including intelligent life) simply can not yet be answered.

Also, this is an interdisciplinary question, not just a question of physics. I'd wager that the first question would be one for physicists though, and that is the question of how the higher gravitational acceleration would affect processes conducive to the formation of organic compounds in nature. That's still over my head quite a bit, and probably will be for the next decade or so (assuming I even continue to study physics -- never know what's coming tomorrow).

Other than that, what Tuco said.

[Shanter]

Thinking more about it, I'm not sure if civilizations on this giant Earth could progress faster than we have here. The day/night cycles (if not 24 hours/day but weeks/months/years) would hinder the growth of plants, causing populations increases to barely rise. Unless plants/trees that could thrive in all day/all night scenarios, it would be hard for any civilization to evolve out of the hunter/gatherer period.

[SalaciousTunare]

Originally Posted by Belefuu

WOAH DUDES, REALLY!?!?!??!!? Hadn't even thought about that!!!

Read the fucking thread.

I did read the thread, I didn't see a post indicating as gravity increased, the likelihood of exoskeleton creatures being the only form of life increases... conversely the lesser the gravity the more likely invertebrates would thrive.

But preach on internet tough guy.

[FulorianC]

Situation A: Physics aside, a planet with the gravitational weakness of Earth but the size of VV Cephei:

There is little chance we'd be aware of other civilizations on the planet. That star has the diameter of Jupiter's orbit - the inverse square law insures that any radio transmissions from that sort of distance would not be received. Radio transmissions don't proliferate through the planet, either; they radiate into space to be lost forever. We'd never know about them.

There is really no chance we'd have any clue they exist, short of satellite photos (with EXTREME satellite proliferation - we'd have to have millions of satellites and millions of people examining in the data to have the remotest chance of finding a civiliation at our current level of technology - even if there were hundreds or even thousands of civilizations on the planet doing the same thing. We could literally have millions of satellites, and and all of them could have millions of satellites, and we could go an eternity without ever finding one another.

Situation B: Realistically, no planet can exist like this, because no natural force exists sufficient to repel the sort of gravity that a body that massive would exert. Nothing could ever form to be remotely that large without nuclear fusion or gravitational collapse into a black hole, as everyone else said. With the terrestrial elements (dirt and metal) dominating rather than hydrogen and helium, a planet of that size would be something on the order of millions of solar masses, maybe billions. It would be easier to estimate with information on the density of VV Cephei.

Regardless, it is far beyond the level that anything could resist gravitational collapse.

The Dyson sphere and Ringworld suggestions made earlier are far better for the theorycraft, though they can't exist without insane levels of technological mastery. Obviously they couldn't be created as a natural phenomenon.

As a total sidenote, I remember on TNG when they found a Dyson sphere. They found Scotty and left. I wanted to fucking throw something at the TV - finding a Dyson sphere would be the most notable discovery in the human race, as the habitable land area of such a thing would be that of millions of planets - in a way, it would be akin to the habitable planets of an entire star cluster, or even an immense portion of the galaxy. They just found it and waltzed on like it was just another curiosity. W T F ever.

[FulorianC]

Some fun with math to see what kind of population a planet like this could hold:

~1750 times the diameter (and radius) of the sun.

The Sun is ~110 times the diameter (and radius) of Earth

110 x 1750 = 192,500

4*3.1415*(192,500^2)=465,648,837,500

450 billion times the surface area of Earth on SuperEarth.

Earth can probably hold around 10 billion people.

465,648,837,500 * 10,000,000,000 = 4,656,488,375,000,000,000,000

5 trillion billion people.

Yeah, we could zerg the fuck out of the universe.

More fun: With 2% population growth per year, a reasonable assumption for growth, how long would it take our current population to grow to this level? (Fill the planet)

5,000,000,000,000,000,000,000 people = 6,700,000,000*1.02^x
5,000,000,000,000 = 6.7*1.02^x
746,268,656,715 = 1.02^x

I'm tired and have been drinking, so taking a log is out: best I can end up by process of elimination is: 738,307,077,168 = 1.02^1380

So, around 1400 years to fill the planet with a 2% growth rate, the speed we had in the 1960s/early 1970s.

[SalaciousTunare]

Originally Posted by FulorianC

Situation A: Physics aside, a planet with the gravitational weakness of Earth but the size of VV Cephei:

There is little chance we'd be aware of other civilizations on the planet. That star has the diameter of Jupiter's orbit - the inverse square law insures that any radio transmissions from that sort of distance would not be received. Radio transmissions don't proliferate through the planet, either; they radiate into space to be lost forever. We'd never know about them.

Not entirely accurate... AM Band radio bounces off of the atmosphere and right back down off the ground over and over. FM is the one that escapes into space.

Interesting bit of trivia, during WWII, 500WLW in Cincinnati Ohio, actually broadcasted in the 500,000 watts or 500kW power range as a test. My grandfather stationed in New Guinea at the time could pick up that frequency without any sophisticated technology for the time.

Assuming all other variables identical on this super earth, then yeah AM could be used to bounce upon the atmosphere across that super planet, it would just be a matter of kilowatts.