Green Baron

*phew* More and more things find their way into space that have nothing to do there. Apparently we are entering a phase where companies or whoever feels like shoots more or less useful things into space no matter what. Guys, if you want to go to Mars, do it now. The way might be blocked in 5 years ;-)

Remains to add that the exhaust gases from the turbine contribute less than the fan in modern day high bipass turbofans. The (smaller) exhaust part is heated inside and so expands (before it was compressed), so the area alone doesn't describe all of the process. The bypass air isn't supersonic, that'll make hell of a noise. It encloses the center stream, which may be close to/around sound speed, thus silencing the whole engine. For this, the two flows are designed to not mix and produce as little shear as possible (immediately after the engine). Source: Wikipedia :-) I am not sure if the two principles can be compared. On the one hand you have the suction, compression, combustion and exhaust (and maybe a mechanical part to turn like a fan or a propeller), on the other mixing of a combustible and oxidizer (or just some boom stuff) and directed exhaust. The first ones are designed to last 10,000s of hours, the latter ones minutes. But i am ready to be corrected :-)

Yeah, and apparently a quite curious and clever one, judging from what it is up to ... :-)

Yep.

And mouth and anus switch during early individual development Amelia Earhart paving a path for women's rights, first woman who crossed the Atlantic solo, disappeared 1937 over the Pacific together with Navigator Fred Noonan, trying to fly around the world along the equator. It is assumed that her plane ran out of fuel and they had to go down short before a refueling stop. The two had an appearance in one of the Star Trek Voyager, where the storytellers had them kidnapped by aliens and brought to the other side of the Galaxy. ------ Bones, found 1941 on a nearby atoll where attributed to a male individual. The bones have been scrutinized anew with more sophisticated techniques and the result is: It was Earhart (99%) and she apparently lived on for a few weeks after the accident. http://journals.upress.ufl.edu/fa/article/view/525/519 Also, a little insight in skeletal anatomy and analysis ;-)

Bring it on pls, we can always translate :-)

Decades of being sprayed with silly movies have left their traces in our culture :-) Yeah, around 50ly away they would frown their skinny or scaly faces, around 40ly away they would start to doubt in our ability to think independently, 30ly away they would send a message home through subspace (why not superspace ?), asking for clearance to proceed despite the obvious hostility, 20ly away they would slap their bony container of the brain, turn around and be content with what they have at home knowing that other places are much worse. :-)

You have absolutely no idea about my understanding.

Same problems here (firefox 52) since two days or so. Sometimes it works, sometimes not. Seems to have something to do with Javascript ?

Single unprocessed astronomy photos are astoundingly uninteresting :-) Blurry white or light gray spots on a more or less gray background. esa.int has a a lot of information on Hipparcos. Information you might already have: A book on the data evaluation. The protocol is online http://emits.sso.esa.int/emits-doc/ASTRIUMLIM/GAIA_TTCSCOE/GAIA-ESC-ICD-00515-SGICD.pdf And the data processing people (Gaia DPAC), but the page runs into an endless loop on my pc here ... That doesn't really answer your question positively :-) ....

That's the point. But it can't be depicted so colourful like huge machines hustling about, doing something useful :-)

But there is loss through friction, the force from the propeller would be greater than the pressure on the sail, so maybe it'll move slowly in the direction the propeller pulls it. Of course, i'll throw the mechanical stuff overboard and go sailing :-)

errr, there is one single more or less civilized planet in the known universe. How relevant is a scale built on hypothetic and arbitrary assumptions and fantasies from the space race age ? Maybe that's why people always think of late industrial age and type contraptions magically put into space to do something with sound and movement. The future belongs to realm of fantasies :-) Nobody can answer that question, the energy production of a star is by many magnitudes too high to do anything useful with it, except let it radiate away or use a small portion with the good old method of energy conversion through solar panels or photosynthesis.

Gaia is an astrometry mission, to measure positions and radial velocities with higher precision than before. http://sci.esa.int/gaia/ Here's the instruments: http://sci.esa.int/gaia/47354-fact-sheet/ tl, dr: it produces images with 2 identical telescopes and an array of ccds. I am sure the data evaluation is done on earth.

It uses megawatts of power, not energy. And how is it melted ? More megawatts for heating ? Because the acceleration might deform the sphere, but not melt it. Btw. the acceleration generates a whole lot of backward thrust on the system. Yes, exactly (if you see it as a closed system and neglect any losses) the same "thrust" (better: impulse) it gained before thorugh acceleration. Not more, not less. So in the end it ends up where it began. ??? No, if you have zero g than the drops just stay where they are. They find no way nowhere ... And why would heat and which law of attraction (?) let the particles rejoin ? Btw., where do the drops come from if you don't heat the thing ? If at all you might have a deformed projectile and/or impact area and that's it. I feel this part needs some more explanation ? This needs an experimental part for verification ;-) The EM drive does not work. There is no reproducible proof, every measurement could be explained by uncertainties in the setup or measurement errors. That's a different thing, as the electromagnet that shoots the needle imparts a reciprocal force on the table it stands on.

"I've had enough, I've had enough, I've had enough of that crummy stuff ..." Thank's for planting that worm in my ear :-) I've had enough rain and low temperatures. Basta !

@StrandedonEarth: about 3.5 ly in roughly 45.000 years. From a graphic on Wikipedia, https://en.wikipedia.org/wiki/Gliese_445 but without citation ... A take on calculation of close encounters: https://arxiv.org/abs/1003.2160 Edit: Gliese 445 is HIP 57544 in the arxiv link.

Oh, sorry, my bad. I didn't write that i meant a hypothetical probe launched towards Gliese 445, not Vger.

And still it'll need almost 200km/s to achieve orbit around that star (30 out of solar system, 120 to match speed, 30 to brake into orbit) or it'll be a quick flyby ...

Well, one would rather want as little intrusion as possible if one far day one would want to have a look. A weapon is totally contradictory to that, a nuclear one even more with all its fallout and mixing up of eventually interesting samples and localities. You will not get much information, except that you made a hole. Could be more than 20 km, these here estimate 28: https://www.sciencedirect.com/science/article/pii/S0019103515000688 The exact energy balance of Europa and its composition isn't known exactly, so models and assumptions must serve for now.

I am at it. Just had to pause a few days. If the weather permits i will cut out the helix parts tomorrow and make the helix. Meanwhile i planned the second storey, the ground floor, sotosay. In principle it'll consist of a 2-track round course with the shunt yard in the center. The shunt yrad will have two tracks leading in, the roll off hill and a harp of 5 departure tracks. Furthermore i'll build a through station in the round course. That'll be around 2k funds for tracks, switches, magnetic switch drives and decoders. The electric backbone for driving and switching is a simple T under the table, with punctures in the floor and ceilings to reach the second storey. Electricity for lights, in the first step only for lighting the shadow station, will have an own ring cable and transformer. And that will be it. But: the place is not enough for the second storey. I need an annex of 1,6 by 1,6m, which makes an L out it. No problem ... Technical remarks :-): cut out a template from plywood, a curve with the lowest radius you accept for your layout, in my case 480mm. Use it to bend your flextracks around it if it comes to narrow curves. Just like a super fast glue hardens in one second but which second, who knows (usually when you test with the finger tip), a tightly bent flextrack will assume any curve but not necessarily (almost excluding) the one you want, causing corners, causing derailings. More soon(tm). :-)

*giggle* is that k insolence, insulance, insulation, insolation or isolation ? Sorry, ignore me ... But an ion driven probe couldn't land on Europa because thrust .... you'd need something chemical and schlepp something with the dV into Europa orbit isn't easy. Possible with current tech ? Edit: Probably not. Let's leave something for the future ;-)

Assembler Menmonics which should exist ;-) Not real, but very funny :-) CBNC Close, but no cigar ....

To support the modeling, a massive flare from Proxima Centauri was detected: https://arxiv.org/abs/1802.08257

Hehe, when computer game and fantasy blend :-) Marsian "sandstone" isn't comparable to the rock hard Mojave formation, if that's what you think. Less gravity, less lasting quartz at the distal end of weathering formed even through billions of marsian years. There is no diagenesis like on earth, that can build compacted layers of rock that were buried under a few (not many) kilometers of sediments and then eroded free again during crustal lift. Nasa uses the word "sandstone" very freely on the Marsian pictures. Just keep in mind: the processes that formed these things on Mars are assumed to have stopped billions of years ago, while on earth they are still up and running. In general, Marsian dust and sediments are very fine grained, more fieldspar- than quartz rich, less hard, more porous. I'd rather guess that Marsian "colonists", if they ever exist, will rather step away from the soft sediments, dust off the ubiquitous basalts and dig into them. Still they'd probably have to stabilize them as they are more porous and soft than earthly lava, but that'll be imo the better approach. But, really, i don't pretend that i am correct, just fantasizing :-)