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"Super-Earth" planets are giant-size versions of Earth, and some research has suggested that they're more likely to be habitable than Earth-size worlds. But a new study reveals how difficult it would be for any aliens on these exoplanets to explore space.
To launch the equivalent of an Apollo moon mission, a rocket on a super-Earth would need to have a mass of about 440,000 tons (400,000 metric tons), due to fuel requirements, the study said. That's on the order of the mass of the Great Pyramid of Giza in Egypt.
"On more-massive planets, spaceflight would be exponentially more expensive," said study author Michael Hippke, an independent researcher affiliated with the Sonneberg Observatory in Germany. "Such civilizations would not have satellite TV, a moon mission or a Hubble Space Telescope."
https://www.space.com/40375-super-earth-exoplanets-hard-aliens-launch.html
[Also Covered By]: GIZMODO
[Paper]: Spaceflight from Super-Earths is difficult
[Related]: 10 Exoplanets That Could Host Alien Life
(Score: 0) by Anonymous Coward on Tuesday April 24 2018, @06:25AM (27 children)
So essentially races on those super earths would have to realize that when they try to leave the planet, they should do so with the intent of immediately setting up a permanent living structure/base/etc on a nearby moon/planet/etc since it would not be feasible to keep making trips to and from the planet itself. That's a lot of homework to do before the first flight.
(Score: 2) by mhajicek on Tuesday April 24 2018, @06:52AM (11 children)
I'm surprised the article makes no mention of space planes.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by zocalo on Tuesday April 24 2018, @07:06AM (10 children)
UNIX? They're not even circumcised! Savages!
(Score: 5, Insightful) by frojack on Tuesday April 24 2018, @08:32AM (9 children)
Wrong. It makes those methods MORE viable. A denser atmosphere (virtually a given on a high gravity planet) provides just as much (if not more) lift capability for a balloon. Helium is still lighter than nitrogen and oxygen. A bag of helium will still rise.
Wings work better in dense air than they do in thin air. And combustion engines produce more power in dense air than thin air.
Basically we've settled on vehicles that work on earth. Then we try out those formulas on what we imagine another planet might present, and make pronouncements about impossibility.
Don't you suppose an intelligent life form on a high gravity planet would try different solutions than ours?
Is ours box the only box within which all alien life forms have to think?
No, you are mistaken. I've always had this sig.
(Score: 3, Funny) by Anonymous Coward on Tuesday April 24 2018, @09:11AM
Getting altitude is only half the battle. the real trick is to be going fast enough so you can get a stable orbit.
Source: Kerbal Space Program.
(Score: 2) by zocalo on Tuesday April 24 2018, @10:04AM (5 children)
And no, I'm definitely not assuming terrestrial conditions/tech - see my other post below - but the problem with hypothetical alien tech is in the name; we have no way of knowing what it is or how it might work making it kind of hard to second guess, so all we can really do is extrapolate from what we do know. Even if aircraft would work on a given heavy Earth, I'd expect that you'd see either a radically different approach to deal with the specific conditions, or at the very least some fairly obvious changes in the relative size of the lifting surfaces and weight ratios.
UNIX? They're not even circumcised! Savages!
(Score: 4, Interesting) by Immerman on Tuesday April 24 2018, @02:24PM (4 children)
No need to burn fuel getting off the ground, balloons will do the job far more efficiently. All you need to do is contain enough helium or hydrogen to reduce your balloon + payload density below that of the surrounding atmosphere. Gravity is irrelevant, and the denser the atmosphere, the less lift-gas you need to accomplish the task, since your payload is more buoyant to begin with.
Once you're above the vast bulk of the atmosphere, you can then worry about getting up to orbital speeds. If you try to do that with a traditional rocket then yes, you'll still have to spend enough energy to keep it from falling while it accelerates, and you're back to directly fighting a much greater gravity. However, an airship-to-orbit (http://www.jpaerospace.com/) giant high-altitude delta-wing -rocket propelled airship could still be feasible - aerodynamic enough that lift keeps it rising through the increasingly vacuous atmosphere as it accelerates. It might take you several weeks to accelerate to orbit, but lift and buoyancy are doing most of the work of keeping you up while you do so.
Plus, since you're not relying on raw thrust to keep you in the air, you can use less powerful, more efficient rockets - even current ion drives typically have around 10x the specific impulse of chemical rockets.
Yes, they might need need to be more technologically advanced before they could actually pull it off, but what's another century or two of technological development in the face of the thousands it took to reach the point where they could even start dreaming up solutions?
(Score: 2) by zocalo on Tuesday April 24 2018, @02:44PM (3 children)
UNIX? They're not even circumcised! Savages!
(Score: 2) by Immerman on Tuesday April 24 2018, @07:47PM (2 children)
Why use helium? Hydrogen is a LOT more plentiful, slightly more potent, and not dramatically more dangerous as long as you treat it with due respect (LOTS of airships used hydrogen safely for years, the Hindenburg was never designed to do so - it was designed to use helium). There's also no particular reason to "use it up" - it's quite possible to have both a balloon and pressure tank, and pump your lift gas between them to control buoyancy.
And building a large enough balloon is a safe assumption for a species even 100 years more technologically advanced than us, we could probably do it today - heck, we've figured out how to mass-produce graphene, which is probably as good as it gets for balloons. If you want to lift a 1000kg point mass (to sidestep payload buoyancy considerations) on Earth you need a balloon large enough to hold a bit more than 1000kg of air - at 1.225 kg/m^3 that's 816 cubic meters, or a sphere roughly 12m across. On Venus air density is 67 kg/m^3, so to get the same lift you'd only need about 15m^3, or only 3m across. Of course you need a bigger balloon as you get closer to vacuum, but that's why the Airship-to-orbit folks plan a transfer from their "deep atmosphere" to their orbital one.
And again - it doesn't matter what the gravity is, your balloon just has to displace a greater than-payload mass of air, buoyancy does all the work. The only place the force of gravity factors in is the necessary strength of the balloon to support your payload - which if you're using graphene might have to be dozens of atoms thick.
(Score: 0) by Anonymous Coward on Wednesday April 25 2018, @07:47AM (1 child)
The hydrogen wasn't the problem with the Hindenburg anyway. Hydrogen burns with a faint blue flame, not the large yellow-orange flames the Hindenburg burned with.
The Hindenburg was covered in a conductive paint due to problems with static discharges. That paint was basically thermite, which just happens to burn with huge yellow-orange flames.
(Score: 2) by Immerman on Thursday April 26 2018, @02:48AM
True, but the Hindenburg is pretty much why hydrogen, and airships for that matter, went out of style. Facts are irrelevant once the media adopts a narrative.
(Score: 2) by fadrian on Tuesday April 24 2018, @02:28PM
There are a lot of other ways to lift weight than rockets. A launch loop [wikipedia.org] would be feasible, for instance. Though, to be fair, having worked next to its inventor for a couple years, I do have a bit of an unfair advantage in thinking of this solution for our poor, gravity-bound aliens.
That is all.
(Score: 2) by HiThere on Tuesday April 24 2018, @04:50PM
I'm not sure that it makes those methods more viable, but it sure doesn't make them less viable.
The problem is, once you get high enough, you still need to lift off against a greater gravitational pull. Orbital velocities are higher, escape velocity is higher, etc. You get this "higher velocity requirement" for free with a stronger gravity.
OTOH, if the atmosphere were dense further out (lots further out) like that of Venus, then balloons might actually be a better first stage. But I'm having a hard time thinking of that kind of a planet as a Super-Earth. It would be more like a Hypo-Jupiter (except for having a necessary rocky core...but most of my life we didn't know that Jupiter didn't have one, and we're still not sure).
With an atmosphere that reaches far enough from ground a nuclear powered plane might be a reasonable "one stage to orbit" vehicle. But that's not a SuperEarth.
Still, with a SuperEarth I expect that you could get to orbit with a nuclear powered spaceplane. It just wouldn't be any trivial exercise. You'd basically need to get above orbital velocity while still in the atmosphere, where you could use the atmosphere as working material for your nuclear powered jet. I'm rather sure that no chemical fuel would be energetic enough to make this work.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 4, Informative) by zocalo on Tuesday April 24 2018, @06:56AM (14 children)
We got to space a whole bunch of intermediate experiments and developments in many fields other than aviation and aerospace over many decades, so even if there is some tech that would let them overcome gravity and reach orbit there would need to be some logical development path that drives them to discover it and all the other necessary technologies required - perhaps as part of the development of more efficient ground based travel - e.g. anti-grav based equivalents to our MagLev trains. Or maybe we've just overlooked something really fundamental about how gravity works that includes a means to negate it, an oversight that has been explored in several SciFi works such as The Road Not Taken [wikipedia.org], quite possible given that we still don't really understand the nature of gravity.
UNIX? They're not even circumcised! Savages!
(Score: 5, Insightful) by choose another one on Tuesday April 24 2018, @07:39AM (13 children)
> perhaps there are other technologies than chemical rockets they could use to overcome gravity instead and might eventually discover.
Yeah, the biggest hole in the article is that it assumes intelligent aliens living on alien (non-earthlike) planets would develop technology along the same lines as earthlings and then get awfully frustrated that it didn't work in their environment. Why assume that intelligent aliens would not have _alien_ technology?
(Score: 5, Touché) by qzm on Tuesday April 24 2018, @10:05AM (2 children)
Nuclear rockets.
We developed them, but not to use due to primarily to politics (not sure to radiation, investigateme designs are very clean, and most are cleaner than true open air testing we did do).
This appears to be yet more 'science' since by people with no ability to investigate or research outside their starting assumptions.
(Score: 3, Funny) by bob_super on Tuesday April 24 2018, @04:44PM
> This appears to be yet more 'science' since by people with no ability to investigate or research outside their starting assumptions.
Silly humans. One day you might understand how to properly use a Higgs Field Crawler and stop letting gravity keep you down.
(Score: 0) by Anonymous Coward on Tuesday April 24 2018, @08:17PM
You build a plain old fission reactor, fueled with uranium or plutonium. The cooling system is open; the goal is in fact to boil the coolant at minimum. The coolant is chosen to produce exhaust containing simple molecules (few degrees of freedom to steal energy) that have low molecular mass.
Hydrogen is great. The mass is 2, or 1 if you heat it enough to make it monoatomic.
Helium is great. The mass is 4. It is already monoatomic, which reduces degrees of freedom.
Helium-3 is as above, but a mass of 3.
Methane, nitrogen, water, cyanide, hydrogen fluoride, lithium, carbon monoxide, and ammonia are other choices. Some of them would be made monoatomic. The seemingly toxic ones might be perfectly fine for alien life forms, not that you can be fussy when trying to launch a rocket.
(Score: 5, Interesting) by JoeMerchant on Tuesday April 24 2018, @12:47PM (9 children)
This "article" was pretty heavily covered in the Niven Known Space series by multiple authors. When a species gets into space is heavily dependent upon the technical challenges of getting into space from their planet. Thus, the less socially developed - more war-like races come from smaller gravity wells. Yeah, it's a lot of assumption, but it makes a great deal of sense that a highly technically challenging planet to leave will require cooperation of more or less the whole planet to do it, while an easy world could have multiple competing factions all independently launching and continuing their competition in space.
🌻🌻 [google.com]
(Score: 2) by Freeman on Tuesday April 24 2018, @05:17PM (1 child)
So, what you're saying is we're an easy world and we can expect WWIII to be "In Space!!!". We're definitely don't have the whole planet cooperating as a whole to achieve space flight. Our space program was actually brought about by competition with a potentially hostile force.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 3, Interesting) by JoeMerchant on Tuesday April 24 2018, @10:16PM
Not really. We were close to using space as a battleground in the Cold War, but... at this point in time, if we were to make a battleground of space we'd just be trashing Trillions of dollars of investment in navigation, communication and surveillance satellites - and I think the business interests of the world are powerful enough to prevent the politicians from doing that. Putting up shrapnel in a counter-directional orbit at geo-stationary altitude is not the same thing as bombing a rice patty or the desert - making geostationary un-usable would be like salting all the wheat and corn fields of the American Midwest.
I think we have enough global social cohesion to keep from slugging it out throughout the solar system, but the future may prove me wrong.
🌻🌻 [google.com]
(Score: 2) by DannyB on Tuesday April 24 2018, @05:30PM (6 children)
The more war-like races probably can't live or fight well in the higher gravity environments of the less war-like races.
The less war-like races, having overcome higher technical challenges, probably know how to build better weapons and defenses.
The more advanced race might have done away with marketing, advertising, lawyers and politicians in the sense that we think of such.
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(Score: 2) by JoeMerchant on Tuesday April 24 2018, @10:21PM (5 children)
You (and I) would hope so, but I think that marketing, advertising, lawyers, national defense forces, etc. are just as much a sign of an advanced society as particle accelerators, telescopes, and entertainment. If you're just scraping by, you can't afford all that crap. I would wish that we could focus our efforts in such a way that marketing, advertising and lawyers were mostly unneeded and unwanted, but we're still all going in too many different directions at once; which is healthy, from a diversity perspective, but disappointing from the perspective of what we could accomplish if we would all just agree to do it.
🌻🌻 [google.com]
(Score: 2) by DannyB on Wednesday April 25 2018, @05:56PM (4 children)
Think marketing / advertising versus search.
Does not scale: every single vendor in the world with a product to sell gets to put an ad in front of YOUR eyes. More than once. (Oh, and gets to call you during dinner time. And gets to erect a billboard on every road. Etc.)
Does scale: when you want something, you search for it. Results include reviews, comparisons, vendor websites, etc.
I think an advanced civilization would not need so much marketing / advertising as we have today. When I suddenly realize that I need house siding, I can find it and who sells it.
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(Score: 2) by JoeMerchant on Wednesday April 25 2018, @06:27PM (3 children)
Some Sci-Fi flop of a movie I watched had a "aliens take over all the humans" basis, after they had control they kept all the stores, etc., but they were just marked as "Store" and people just walked in and took plain brown wrapper with simple label products as they needed them from the shelves, no payments.
Makes sense, not sure that people are wired to ever be able to work that way.
The innundation of crap that _still_ arrives at my mailbox every day is unbelievable... I'm pretty sure that more is spent on the paper that reaches us every year than we spend on products advertised in that paper, certainly more than we were influenced to buy by that paper, since almost all of it hits the trash can as soon as we're sure that nothing important got buried inside.
🌻🌻 [google.com]
(Score: 2) by DannyB on Wednesday April 25 2018, @08:54PM (2 children)
People could probably deal with not paying. Taking products that are wrapped in plain brown paper.
People will still have preferences. But probably not Brand preferences.
Do you want the Cherry Flavor or Orange Flavored . . . Brawndo! The Thirst Mutilator! It's Got Electrolytes. (Or without electrolytes)
Do you want the restroom tissue with Ronald Rump's face, or Killary Flinton's face?
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(Score: 2) by JoeMerchant on Wednesday April 25 2018, @09:37PM (1 child)
Funny you should mention this - I saw a Trump-Pence logo bumper sticker today and had the very same thought.
🌻🌻 [google.com]
(Score: 2) by DannyB on Friday April 27 2018, @06:47PM
I was referring to two hypothetical people. Not actual people. :-)
yeah, right
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