Green Baron

Pilot of a small aircraft, broken english language P: "Bratislava, this is xyz123, request landing" pause P: "Bratislava, this is xyz123, request landing" T: "Roger, xyz123, you are cleared to land [landing info]. But please note this is Vienna" P: "Roger Bratislava [reads back landing info more or less correctly]" T: "Once again, xyz123, this is not Bratislava, this is Vienna" P: "But why, we want to go to Bratislava" T: "Roger, xyz, discontinue approach, climb [altitude] heading [heading], vector to Bratislava" We may assume that the confused guy got home. More fun

P: "errr, mission, this is [aircraft/pilot] i ... uuh... forgot my callsign .." M: "roger, pilot, adopt new callsign 'Idiot One' Idiot one completes mission under new callsign. P: asks for landing info T: "runway xx, wind yy, no other traffic announced. btw. is this the same aircraft that declared an emergency 2 hours ago ?" P: "No, only the same pilot." ATC: "XYZ123, turn left and report heading." P: "Roger ... 120, 130, 140, 150, ...." (turns wrong way and blocks frequency) C: "Phantom crossing airfield without clearance state your callsign !" P: "I'm not silly" G: "xyz123 approaching runway ab, checkcar on the runway." P: "Roger, will check the car on runway" P: "apron, please call us a fuel truck" A: "Roger, you're a fuel truck" ... and thousands more :-))

Recent Jupiter amateur photos. If you skip those with a colour tendency you get a feeling what Jupiter looks like to the human eye in a telescope.

If i knew about the future ... :-) These all are apparently opinions. And so i can only repeat mine. "Terraforming" is a scifi concept. Processes take at least hundreds of millions of years and planetary rates of production / consumption of elements. For Mars it's too late anyway since the sun will in a billion or so years (maybe earlier) be too hot. Mars had it's chance and didn't take it (born to loose) ;-) I do not see any technology that could move or produce even a miniscule part of what is needed to build and maintain a stable state; to set up planet wide circuits to keep a biosphere alive. Besides a long breath and ludicrous amounts of energy one would not only need a deep understanding of all the processes but also the knowledge of which parameters control what (and there are more than the usual game setting :-)) and how to control these, with all side effects etc. We can't do this on earth, not even close. A colony, maybe. In a few hundred years, if we carry on with our progress and don't beat each other up and spend more money on scientific progress. But right now we weren't even able to build an "autarchy" in a desert where there is groundwater (maybe 2000m deep) and air to breathe. Not without continuous support from outside for spare parts, healthcare, etc. And Mars is a little harsher.

Question, because i am curious, is there anything more, any serious up-to-date thoughts on "terraforming", maybe taking into account for recent works on planetary / geoscience ? I mean, more than the usual second hand news magazines ? The few words that Musk shed until know don't really make me believe that he has a plan. I know of none but that really means nothing ...

Actually, yes, correct, short explanation why: many who searched education in early / high medieval times (let's say until 1400+/-) entered a monastery, or had to travel far and long (medicine or astronomy/astrology from Muslim countries at these times !). Whether one can call that control or suppression ... i doubt it. That came up later, towards the end of the medieval (using definition 1525 as the beginning of the renaissance here) and especially in renaissance times. Yeah, well inquisition started earlier as a means to homogenize catholic belief, not that much as a control mechanism. The high times with mass murder and regular torture ("Hochnotpeinliches Verhör", i could not find a quick translation, if you're interested ...) etc. (Tomas de Torquemada, Spanish Inquisition) took place 1400 and later, with the highest toll indeed in renaissance times. But that is not my field of expertise, i am underway 10.000 before now and earlier. Much earlier :-) What was the topic ... a terraforming Mars.No, we still won't :-)

... but you must cite it correctly :-) I have a geoscience background and followed the development of climate change research as well as political elements trying to steer it, both sides, during the last 20 years. @adsii1970, you are a historian and so have a scientific background as well, but here you mix up opinions and findings. Also, there is a certain body of thoughts connected with denying of science, especially this kind of science, that is not mine. Must say this, it's part of the light :-) Lighting a torch: While many details and even principles are still in discussion and deserve further research, the human influence is by now very well proved and even in large parts understood. Just open science & nature and elsevier journals and perform a search and stop focusing on doubtful second hand sources. The abstracts of articles are free for everyone to read. I am not going to the level of disutes, i did this until a few years ago, but meanwhile things have changed and humans are changing climate in a most concerning way. Oh: Hail The Kosmonaut! :-)

You make it intentionally political and i do not like this. You put your rightful opinion as scientific finding which is wrong and fling at us journalist articles as if they had a verifiable scientific background, which i do not have the time to check against recent publications. Show me a single SCIENTIFIC article, a publication by the geophysical unions or the scientific journals and we can discuss further, otherwise this is just hot air with political intent and fruitless to follow. Alternative facts, eh :-) ? [snip]

We ca say so with the help of science. It's measured and published. Climate models do indeed take care of a lot of things from radiation balances over element cycles via sinks and wells and dependencies of a lot of physical and chemical parameters in the different spheres, conveyors and exchange systems. Volcanoes are just a very very small parameter in the models, their different types and appearances are well included. Need to say this before this gets locked :-)

Ok, i won't get into politics because that'll not make the picture better. If terraforming includes building up a biosphere then nobody (edit: including of course me :-)) here can estimate the complexities and interdependencies earths biosphere has. Just to give you a feeling of what we are talking about: it took about a billion years from the beginning of an oceanwide production of oxygen through photosynthesis until a remarkable rise of oxygen in the atmosphere because other stuff had to react and bind free oxygen, mainly through weathering. This is beyond technology or will. A colony, maybe in 200 years, if all goes well until then, but "terraforming" ?

Ah, but that is because we as a species just exploit without responsibility and leave thoughtlessly our rubbish behind. Like bacteria in a petri dish that grow until resources are gone and then die over the excrements. It is not a planned deed or concerted action that we "produce" co2, it is just irresponsibility. Archeology teaches us that people, once houses and sessile living was invented, did the same until they had to move on or beat on the neighbours. Personally we may take some action these days like separating rubbish or walking instead of driving, but when it comes to struggling or to cut down on wealth or gainings "we" leave it. Read the news :-) As to the op: no, of course we can not terraform a planet. Energies needed and masses relocated are far beyond what is even marginally thinkable. Even on earth you need 100.000s of people and a continent wide production chain and economy to build e.g. a large dam to produce electric power. We can't even take 20tons which might represent a habitat for 5 people for 2 years, to mars and it doesn't look like this will change in the next 2-3 decades. We can't even "terraform" a desert or a glacier on earth. Only with continuing support from outside can people live there, and it is not funny. p.s.:the processes we talk about are in the billion years range. Maybe faster on the discovery channel ... :-)

Yep, in case of complete pressure loss one only has a few seconds before falling unconscious. It's not like holding your breath. I just didn't expect a small capsule, designed for a rocket powered ascent and an atmosphere reentry from the mun, to have structural problems with an internal pressure of let's say 0.7 or 0.8 atmospheres.

I can imagine that the residue and water have formed sort of cement and the two parts have realized that they are one. Since the cement is from the same material as the mirror (SiO2) you have a 50/50 chance of damaging the one or the other. Chance has been taken :-/ SiO2 won't dissolve in acid, like the Ca-part of a "real" cement would, so trying it with vinegar-cleaner or so wouldn't work either. You can't fix it on a turning machine (and it would probably be too expensive) to remove the lap mechanically ... But they offer it, they want to help get over the frustration :-) Edit: that reminds me of one of my early failures: i made a bow, i mean i wanted to make a real strong longbow, medieval style. It turned out to be a hiking stick. So i took a weekend course. And another one. Since then i have made some 50 longbows, the best one had 80 pounds of pull force, the arrows flew through a fire protection door. It broke one day, i grilled a sausage with the remains :-)

Gosh ! Well, it so happens with many hand crafted things that the first try is for learning. My list of failures is long and it is still growing ... :-) Don't be too frustrated !

So, there is no earth ? Protoplanetary disk, accretion disk, rings around a planet, they exist. They are formed by physical effects and they do cause physical events. You and me for example. Or are you just kidding ? :-)

Hm.... one could use pure air from a single tank. or nitrogen if the "inhabitants" had an independent oxygen supply ...

Without wanting to go into explaining our senses of perception or discussing what "is" and what "is not", one of the underlying principles of natural science is to find structures and patterns and to look for the physical reasons that form those. So, imo, yeah there "is" a disk. And an explanation "why" there "is" a disk.

A question i always had since i first heard that: why did they fill the first american capsules with oxygen ? What's the benefit over all the down sides (corrodes, reacts happily, ...)

Very nice, and almost no distortions any more and brilliantly sharp. For comparison, would you be interested in trying like 20*2min, and maybe even 20*4min and see if you can get more detail ? It is my plan when conditions are right next time. I tried this in winter and remember that Pixinsight accounted for the exposure times and combined the brighter parts of the different exposure times correctly. I hope i have to deal with an unexpected open sky at night soon ... :-)

Good job. Hail the Probe

The left image shows comatic aberration, the stars are distorted, the farther away from the center, the more. You don't realize that visually as you watch only on the optical axis, but a large camera chip would show it as it has a larger area than the pupil. The difference is that the "EdgeHD" thingies have a corrector for the comatic aberration built in (aka coma-corrector), the right image shows only little coma. The advertising is bit misleading, you don't need a new scope. You can have the same effect with a separate (but much cheaper) coma corrector, one that fits your scope/focuser/camera. You don't need one for visual. As to what is "better", a mirror or a lens ... if it is only the image quality then nothing tops an apochromatic refractor, but a well made mirror can come close. "Real" apos larger than 120mm aperture are expensive, though there are so-called ED (referring to the glass designation of 1 or more elements of the objective) or half-apos (german: halb apo). That are three element objectives with an apochromatic correction that go for about half of a real- or super-apo to serve a wider market. Much cheaper are the entry level 2-element achromatic objectives, but then you're probably better off with a mirror. As said, you get a large aperture for comparably little money.

Sequence stratigraphy ? Like the youngest at the top ? And using the ingredients to obtain a date ? Valid if left alone in peace for a long time. Hmmm ... nah, to many discordances ('splosions) and unconformities (technical or other difficulties) here :-)

But what exactly is the argument ? The isolated look on the force comparison has no meaning here. The sun's field is almost the same for earth as for the moon. What matters is the change of the forces in the combined gravitational field as the moon revolves around the earth and is perturbed by the sun. But only as much as the suns gravitation changes over the distances the moon has on its orbit. We call that tidal forces. Take the sun away, it wouldn't change the moons orbit around earth (well, a little, by the perturbations that result from different distances to the sun the moon has on its orbital path). Spoon ... fork .... hunger ! I'll be back ... :-)

... with an accretionary disk ? :-) You're right, i got too upset for something unimportant. Greetings to @K^2, no offense meant !

The article which i just skimmed makes imo the same mistake as pointed out above: it takes the force the sun has on the moon but ignores that nearly the same force is exerted on the earth as well. Orbital elements are the semi major axis, eccentricity, argument of pe, longitude of an and inclination. If you give me these for the moon around the sun in a sun centered refernce system (choose the plane of reference) then i am content. I bet nobody can because they do not exist. But they exist for the earth, or more precisely for the system earth/moon as they are clearly in an orbit around the sun which can be described by the aforementioned elements. Also the definition that puts the moon in a sun orbit is so generalized that, had i more time, i would start to calculate the g forces the galaxy (the Local Group, the Great Attractor ...) has on the moon. Do we have the moon then in a galactic orbit or even bigger ? I mean, yeah, in the same philosophical sense like i live on earth this is maybe the case, but does that make us smarter ? The orbital parameters help us to calculate orbits(!), define the in OP mentioned moons of Jupiter (topic :-)) and let us play ksp. So what do you guys think about the application of Kepler's laws of motion, Newton's or Galilei's gravity, Hill or Roche sphere and Lagrange points in respect to orbiting bodies ? Too narrow-minded ? :-)