And yet if a certain other forum member posted the X-Files comment you would no doubt have relished posting an acerbic comment about it.

If you have nothing coherent to say on this thread I would take your own advice and not visit the thread again.

Dude, relax. If it bothers you that much just put me on your ignore list. Trust me, I won't lose any sleep over that.

I'm chilled mate. Just saying it like I see it.

Have a great weekend.

Nah, I like your views on films/TV.

Do you have a link to the US Military's most advanced drones?

I have a couple drones that run on small batteries, and they can fly 35 mph, change direction on a dime. And these are the low end Mavic Mini drones that are around $500.

Just imagine what one can do with a $1.2 billion drone.

I doubt the Pentagram, with it's "highly efficient" R&D and procurement folks could make a competitor for the Mavic for less than $3 Billion.

Coming in late to this thread, and this deserves highlight, as it made me literally spit coffee on the monitor.

On space aliens:

There's a huge mass filter on rocketry, known as the Tyranny of the Rocket Equation. Turns out the Earth is (once again) in the Goldilocks range of mass that allow rockets to escape gravity; if the Earth was slightly larger in mass, it would simply be impossible to launch a rocket into orbit. The percentage of weight of propellant to the rocket itself would go over 100 percent. The best we can do is about 4 percent payload allowed...and yes, there is a point of diminishing returns to the size of rockets.

Why does this matter? If the Earth was slightly less in mass, the core of the planet would probably cool (or maybe not, thanks to Theia giving us more core material than we deserve); and without a hot spinning core we wouldn't have a magnetic field and lose our atmosphere, as Mars did. Life - we're talking complex life - really suffers if there's not a decent atmosphere that supports liquid water.

Assuming that complex life follows the same rules elsewhere as it does here (and we have zero evidence that chemistry and physics aren't universal), that means that smaller planets just don't have the moxie to give us Little Green Men.

Larger planets, however, could. Even a planet twice the size of the Earth could be very Earth-like, given a proper sun and orbit. There could very well be a Super Earth out there with Little Green Men toiling away on their Internet arguing that interstellar travel is impossible as gravity makes launching something into orbit impossible - thanks to the tyranny of the rocket equation.

So UFO's being full of LGM is remote in the extreme, owing to the filters that life has to navigate through to get to interstellar travel, let alone the distances required.

Excellent points, Dart.

Plus, without a magnetosphere, we'd be baked by cosmic radiation--though, the atmosphere would likely be stripped before that happened, such as what has happened with Mars.

That is literally the best post I've read. I've learned something today. Thanks.

well said, but i see though your bias....you assume LGM comes from space, no one said that. what if they come from inside earth ? can we really assume all dinossaurs the longest living species on earth save for bacteria,fungi and plants would be wiped by a single cataclismatic event, when they evolved to survive many others before,the change of earth geography,but a bunch of lizard-like mammals ,small rodents and fish did just fine ? i think not !

How about "What is propellant" for 1,000 Alex?"

Propellant a couple hundred years ago was coal fired steam. Methnks ( i know, scary), that maybe the Tyranny of the Rocket Equation is applying our own scientific limitations.

How high would a coal fired steam powered rocket have flown? If chemistry and physics are universal, maybe we just haven't discovered everything yet...

it also assume that the concentration of said elements are the same as on earth.

Ah, Blade, my friend, you have hit on my favorite Alternate Theory of all time.

Forget the Flat Earth. It's stupid and boring.

The Hollow Earth, however, has dinosaurs, aliens, and the occasional Nazi left over from the secret WWII bases.

Oh, we know quite a bit about chemistry.

Turns out the most bang for buck is good ol' Hydrogen and Oxygen.

Who says "life" has to be carbon based and breath oxygen?

Yep.

The stellar fusion process is pretty consistent, as are supernovae.

Basic chemistry.

The problem with other elements that can bond to themselves, like silicon, is that the chains are very short - usually no more than four atoms long. Only Carbon can make long chains with itself and have other elements paired with it as well.

So yeah, life has to be carbon based, or at least complex life.

As to oxygen, you're correct. For a big chunk of Earth's history, life didn't rely on oxygen; it was anaerobic.

Along comes primitive algae, trying like hell to get some of the energy from the sun that the damned ol' cyanobacteria was gobbling up, and going a different, less efficient route. Photosynthesis allowed them to use the parts of the spectrum filtered by, and as a byproduct they released oxygen.

This lead to the Great Oxidation Event, which is a nice way of saying Mass Extinction.

what is complex life and what is simpler life ? so you are saying its possible !

Sigh.

Non-carbon based life? Nah.

Non-oxygen complex life? Possible, but difficult. The problems are when one goes from single celled to multi-cellular; respiration and metabolism become very difficult.

And let's not forget that Oxygen in the atmosphere in quantity makes an ozone layer, which cuts down on solar radiation, giving us a huge bonus from the magnetosphere. Granted, we have a sample size of one, but anaerobic life had hundreds of millions of years to evolve from single cell to multi-cellular and didn't (in meaningful ways), but from photosynthesis to multi-cellular took a lot less time.

I think you're being a bit coy on asking the difference between simple and complex life, so I'll spare the TL:DR post that would go with that.

[edit] Turns out there is one anaerobic animal found:

https://scienceblogs.com/scientificactivist/2010/04/07/anaerobic-animals

If it is ever exposed to an oxygen environment it will probably die.

Good points on fusion and stellar fusion.

I would think space dust at anywhere near light speeds would be a huge problem also, even if that snails speed makes interstellar travel seem silly.