Not really. Not only is that article kind of sloppy (and in its categorization, our system falls into the “Similar: the masses of neighbouring planets are similar to each other”) but I think inferences about how similar a system needs to be to our solar system in order to have potential for developing sophisticated life are predicated on the assumption that our developmental path is the only plausible way. Earth has had a pretty unique history of planetary development that is unlikely to be frequently repeated, but it isn’t necessarily the ideal or even most probable path toward an advanced form of life.
Contrariwise, many astrobiologists are of the opinion that life may be more likely to develop on icy worlds with a liquid ocean (like Enceladus or Titan) than on the nearly unprotected surface of a rocky world that happens to be at the right distance to have liquid surface water, with ecology driven by tidal energy and protected from the vagaries of solar flares and other sources of hazard. Such worlds could exist around nearly any star that has a main sequence lifetime long enough to form planets, i.e. all Class M through F stars, and perhaps even some Class A stars that will fall off of the main sequence and into a red giant phase. If true, that significantly changes the ne and f l terms of the equation. And although the parameters in the Drake equation are stated as means, they should really be identified as distributions with uncertainty bounds which would actually give a useful estimator of the likelihood of discovering life, especially with an additional parameter that considers local density and extinction distance for viable signals.
But moons have their own set of issues. Complex life is unlikely under an ice sheet, or on a world w/ a surface temp of -250 F (Titan). The magnetic field of the primary would fry anything unshielded on the surface. Tidal locking will increase the “daily” warming and cooling cycles (where a day could equal many Earth-days), requiring life to be more hardy, esp. complex multicellular creatures. Smaller moons would represent a constant long-term impact danger.
As for other planetary configurations, ours may be the best bet. Having gas giants close in with some terrestrial worlds would likely make the orbits of the latter unstable. We already have strong proof that our giants have migrated in and out; do that thru the terrestrial habitability zone and it’s game over, man. Even given Jupiter’s current position Mercury could still be ejected within the next few billion years if they get in resonance. [cite]
The jury is still out on whether Jupiter (and Saturn to a lesser extent) were more our “guardians” or our nemeses (would they fling more asteroids and comets in towards the inner terrestrials, or eject them out of the system forever), so an all-rocky lineup may be pretty optimal, but may indicate other substandard factors, like low metallicity.
The anthropic principle however biases any factors we observe towards being helpful if not optimal for our kind of life, at least, by definition. Doesn’t mean other possible avenues exist, but we KNOW this set does.
The biochemistry that would occur on a cold temperature world would certainly be slower, but could also be more complex. Ecosystems underneath and ice sheet or deep under opaque clouds wouldn’t be driven by photosynthesis or other conversion of stellar radiation (unless there was a nutrient-producing layer in the ice sheet or clouds) but could be driven by any number of other processes including tidal energy (which is vigorous enough to drive active vulcanism on Io) or radioactive decay (which drives both tectonics and the geodynamics of Earth), which could produce enough heating to allow faster biochemical reactions. Being under an ice sheet or a thick cloud would actually be more protective than the exposed surface and thin atmosphere of Earth, perhaps allowing it to endure even through large celestial perturbations and in the more radiation dense region closer to the center of our galaxy or earlier in galactic evolution when supernovae were frequent a occurrence.
Of course, any complex life that evolved under such conditions would be very different from terrestrial life on Earth, and even different from our evolution of marine life. And the technology they could hypothetically create would develop along very different principles. As you note, inferences based upon our experience have an inherent ‘anthropic bias’ toward how we think life could work and what we would look for in biosignatures and technosignatures in other planetary systems, but I think we should be open-minded about the diversity of potential extraterrestrial life.
Starship isn’t there in the test. I think squeegee means the upper part of the booster.
Liquid oxygen and liquid methane are fairly similar in temperature, which is part of why it makes a good propellant combination. The upper part of the tank contains the methane, and In fact, it is frosted–it just isn’t filled up all the way. There’s a band, maybe 1/8 of the total height, that represents the liquid methane part. Above that is hot methane gas used to pressurize it, and that section doesn’t collect frost.
Below that is the liquid oxygen tank. Curiously, that does appear to be filled all the way. Or, at least the frost goes almost all the way up. It’s possible the pressurant gas (oxygen) is colder than the pressurant methane, and collects frost as a result. Or maybe they just decided it would be a better test with a full O2 fill. It’s easier to deal with afterward, anyway (compared to the methane) since they can just vent it if required.
They also demonstrated the fastest launch site turnaround since 1966 (and set a SpaceX record):
The quick Atlas-Gemini turnaround was required by the mission profile, though, and they undoubtedly spent a lot of money and resources to make it explicitly happen. In the case of SpaceX, it’s just because they’re launching so frequently that sometimes they line up nicely. Every four days on average, but with some randomness thrown in.
I think the four they refer to are Gemini 8, 10, 11, and 12. Gemini 6 was earlier (1965), but the Atlas-Agena failed to launch. Looks like they’re counting mission failures, but not launch failures in the four.
I like the fact the lens has its own control panel separate from the camera.
I was mostly boggling at “ISO2500”. The last time I dabbled in film SLR photography, ISO 100 was the goto stuff and ISO 400 was a grainy mess suitable for limited purposes only.
I think I understand that ISO speed is a bit of a hacked-together idea as applied to electronic light sensors. But insane sharpness and roughly 25x the sensitivity of good quality old film? Wow. We’ve come a long way Baby.
