So is it better or worse chance to be habitable than Mars/Venus would have if discovered elsewhere with its current orbital patterns and size?

Also possible, yes, but not even close to equally probable.

Never give up on knowledge as beyond us! We are always finding new ways to search. People looked like real psychos trying to fly for, presumably, all of human history. Until someone figured it out.

So, I agree with you that life is likely out there and in abundance given the vastness of the universe. (Even if I think it’s very equally improbably that advanced intelligent life has visit Earth 😂). Refer to Drake’s equation that whittles down that high probability to possibly 0.

That said, your question of “what would it look like” has been addressed by Carl Sagan in his old Cosmos series. Considering that humans and a tree share 25% of the same DNA yet are unrecognizably different, you can safely conclude that an alien species that shares 0% of our DNA (or any DNA at all) would be entirely different. So forget those movies where humanoid aliens are bipedal or look like giant insects!

So Sagan and other xenobiologists rely on convergent evolution theories — like why a shark and a dolphin have similar “flippers” — to speculate on life forms that rely on various environments (gravity, water, temperature, atmosphere, orbit and rotation, radiation, primary star type and distance, living energy transfer, available minerals, etc etc etc) yet might have evolved similar solutions to life here on Earth.

…or it would look more different to us than a virus or amoeba does.

It's not that we haven't found intelligent life out there, it's that the aliens haven't found intelligent life here. There's no interest in us, yet. Maybe one day many, many yrs from now. But now, we're infants. We do nothing of interest to them

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If you're interested in this topic, Anthropic Principle, is a good place to start.

It's very challenging to say. People have tried to ballpark it, concepts like Drake's Equation. But they all rely on assumptions that we're really not capable of asserting.

Still, it does allow us to consider the topic in ways that are more fruitful than just random consideration. After all, as technology progresses, we do become better at defining many of the assumptions, giving us a more accurate range in which to find intelligent life.

I think most considered people accept that life in the Universe is robust. Intelligent life however?

That's a much harder thing to say, because it requires a lot of things to go just right. Many of which (Abiogenesis) we don't even understand.

So we search. But that poses its own unique set of challenges. The issues of searching such a vast area for signs of intelligent life.

A lot of really smart work has gone into narrowing bands of information that we'd expect to see from intelligent life. From particular radio frequencies to different combinations of chemistry that would be challenging to reproduce naturally.

But still. The Universe is beyond massive. Needle in a haystack isn't the appropriate comparison. Needle in a haystack of a sky full of haystacks is the more apt one.

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Life started here with stardust and the perfect environment. It's silly to think that the stardust that made us didn't find its way to other compatible planets as well.

Sometimes it takes quite a while for a theory to be practically implemented.

Work on Scramjets started in the 50s, with engines working in laboratory conditions in the 60s, but didn't operate in real flight conditions until the 90s and have only recently started to approach practical use - it's hard to say exactly where they are today since most such projects are classified.

I'm not sure when the theory for FFSC engines dates to, but the first example was built in the 60s. However it was unable to sustain stable combustion and the first stable engine wasn't tested until the early 2000s. The first test flight of an FFSC engine wasn't until 2019, and the first practical use will probably occur this year.

The basic theory for fusion dates back to the 1920s, with proposals for fusion power specifically dating to the 1950s, but it still hasn't gone anywhere, yet. We have been making steady progress, so it may still go somewhere given more time. The recent scientific breakeven at the NIF was a significant, if not directly applicable milestone.

Advances in computer control technology have been instrumental to a lot of the recent progress in the aforementioned applications. Having the theory is one thing, being able to control a complex and delicate process in practice is another.

Maintaining continuous rotating detonation has proven quite challenging in the past, typically breaking down due to instabilities in a matter of milliseconds. The fact that NASA were able to run this engine for what looks like about 8 seconds is very promising indeed.

The launches are in the northerly part of the state, but the real “Florida experience” is in the far south, quite far away.

The road trip down the coast isn’t amazing but it can be a fun drive if you take your time and stop at a few places along the way.

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A Pulse Detonation Engine was proposed for DARPA's Blackswift hypersonic test vehicle from the late 00's. Pulse Detonation Engines are engines that use the same detonation concept but are still inherently air breathing jets and not rockets. I'm not aware of if one was ever built though. It's my understanding that contemporary hypersonic missiles use solid rocket motors to get up to speed and then glide to their target.

This will give you 10% or so better performance. That's not nothing, but it's not the difference between asteroid mining being viable or not.

It’s also possible we are a fluke and literally no other intelligent life exists anywhere in the universe and never will again for a long long long time

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

|Fewer Letters|More Letters| |-------|---------|---| |Isp|Specific impulse (as explained by Scott Manley on YouTube)| | |Internet Service Provider| |JPL|Jet Propulsion Lab, California| |LEO|Low Earth Orbit (180-2000km)| | |Law Enforcement Officer (most often mentioned during transport operations)| |NEO|Near-Earth Object|

^(4 acronyms in this thread; )^(the most compressed thread commented on today)^( has 14 acronyms.)
^([Thread #8500 for this sub, first seen 30th Jan 2023, 22:21]) ^[FAQ] ^([Full list]) ^[Contact] ^([Source code])

Your country might have a public internet but mine doesn't.

I would happily pay a government entity as opposed to my ISP if the service was just as good but until a public option becomes available I pay for my private internet with a monthly bill.

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Heat can be transferred in three ways: Radiation, Conduction and Convection. Conduction is heat transfer by two solids touching. Or when you put your hand on your heater, you feel your hand getting warmer. Convection is heat transfer to fluids (gases). That is why the air in your room heats up when you put a heater in it. Radiation is the weakest form of heat transfer, by far. But if you aren't surrounded by an atmosphere or ocean to dump heat into, and instead are surrounded by a vacuum, radiation is the only way to get rid of heat. Conductive transfer will constantly heat up the spacecraft until parts start to melt if you cannot radiate the heat fast enough. Hence the need for large radiators on spacecraft that produce a lot of heat, e.g. the ISS or even the shuttle, whose whole payload bay doors were used as radiators and needed to be opened somewhat quickly once in orbit or the shuttle would overheat.

Air-breathing engines aren't comparable to rocket engines. They have big specific impulse numbers because the specific impulse is no longer the impulse available from the propellant, but what's available from just the fuel after that fuel's been combined with the air. And since it's wildly variable with airspeed, it only makes sense for craft that cruise in a given range of airspeeds...in this case, Mach 5 and less.

Great info, but I’m not a fan of the stacked bars method of display.

Thank you.

You’re not the Hero we need, but the Hero we deserve.

Is this tech only suitable for space travel or can be used to launch from the planet as well?

Hyperion is also one of like, only three known natural satellites in the solar system that isn’t tidally locked with its parent planet. A very unique satellite, indeed!