1702

Oh yeah i’m happy with all the theory that life exists and is probably abundant, but we have as of yet not found many clear examples of that (beyond very basic ingredients in things like comets, methane on mars etc). We need that real ‘We have found a complicated life form and it is not from earth’ event to win around more people to enable us to think bigger picture.

1703

Our solar system is probably not atypical and planets in the “Goldilocks” zone are probably equally commonplace. There are a few things that may set the Earth apart, however.

The first is a strong magnetosphere, something that our nearest neighbors (Mars and Venus) do not possess. We don’t know whether a strong magnetic field is a rarity among small, rocky planets or not. Mercury, Jupiter and Saturn all have reasonably-strong magnetospheres, so in our solar system it seems to be more-or-less a coin-flip. We really don’t know whether the magnetosphere is vital for life developing or not – the general consensus is that it shields us from a large amount of solar radiation, but we don’t know if that’s a deal-breaker or not. The magnetosphere may or may not shield our atmosphere from the buffeting “solar wind” too… some theorize that we’d lose atmosphere at a higher rate without it, though others point to Venus’ atmosphere loss at about the same rate as ours. But it’s hard to do an apples-to-apples comparison because…

The Earth is really a dual-planet system. Luna (our “moon”) is a small planet that was most likely calved from the Earth herself while the solar system was forming, and is in an unstable, far-too-close orbit and is ridiculously-large for a satellite. Out of the billions of stars in the galaxy and the untold trillions out in other galaxies it’s likely that the Earth-Luna system situation is repeated many, many times, but the chances of an oversized satellite in close orbit around a rocky world in the Goldilocks zone is probably really, really rare.

So how important it Luna for life? We don’t know, obviously, but there is some evidence that it might be pretty key:

The oceanic tides that the too-close and too-large Luna causes are extremely powerful and likely vital to a mitigated climate. It’s very likely that without the moon and tides, seasonal temperature changes (and the Earth’s orbital progression) would be much more severe than they are with the moon. Not to mention that the planet’s leisurely 24-hour rotation was probably caused by the impact that created Luna in the first place; otherwise we’d have 8-hour days and 100-mph sustained winds would be commonplace. Is that important to life? Dunno, but probably.

The tides themselves (specifically the wetting and drying of water on shores) may have been a big driver in the creation of life to start with. Not that it couldn’t have happened without it, but it may have been accelerated significantly: material is thrown up on a hot rocky shore, it dries out, then is wetted a few hours later and cooled, then warmed and dried again. Without Luna, we’d still have tides due to the sun, but they would be much less severe than they are now, so maybe life wouldn’t have been quite as likely to sprout here.

Likewise, Luna affects the tectonic forces on the Earth. We don’t really know how much, but the presence of a massive satellite causes some heating of the crust since the moon’s orbit is not the same as the planet’s rotation. Some scientists theorize that the moon’s pull actually causes some of the convection that moves the plates hither and thither. Enough to make a difference in the creation of life? Doubtful, but maybe.

The moon probably shielded us from a mess of extinction-level asteroid impacts in the last few hundred million years. Not all of them, obviously, and Jupiter probably grabbed many more, but a bunch. A deal-breaker for life? I’d say “no”, but maybe a deal-breaker for what we consider “higher” life.

And probably VERY important is the atmospheric “skimming” that the moon causes. As noted above, the Earth loses atmosphere at a rate equivalent to Venus or Mars, but we’re a bigger gravity well and should actually be retaining more air. Without Luna our atmosphere would be far, far thicker… maybe not Venus-level thick (that’s due more to temperature), but it’s likely that we’d have permanent global cloud-cover. Important for life? Could be.

Anyway, I’m of the opinion that we’ll find life almost everywhere. But the Earth is pretty unique so “M-class” planets are probably not as common as Star Trek would lead us to believe.

1704

Oh, I’d still expect we’re the only spec of life in this galaxy. I’d just be very surprised if all of these conditions weren’t replicated in quite a few other galaxies. Having an idea of how common the rocky planets in the right orbits are gives us an idea of how many chances we get at all the other things. Within a few orders of magnitude of the number of stars, it seems. That’s a lot.

1705

Interestingly cosmologists believe that the supermassive black holes in the centers of galaxy may regulate star formation by blowing out interstitial fundamental gasses when they encounter a particularly energetic ‘munching’* event. Eventually these gasses will descend back into the galaxy, kicking off star formation again.

It’s also interesting (to me) the reason accretion disks are so energetic is because they literally have so far to fall before entering the singularity; they’re literally turning an enormous amount of local potential energy into thermal energy as they fall. That is, the accretion disk isn’t this crazy thing because “black hole” or whatever, it’s because black hole means ultradense object that incredibly small in radius (a point object?).

*technical term

1706

Actually i was just thinking the other day of the incredible number of ways that the Earth IS unique, which could be used (by someone wanting to) as evidence of a divinely ordered universe. Or at least our Earth is supremely lucky. We probably take for granted the huge number of coincidences that the Earth represents. Issac Asimov had a big book of coincidences that was pretty amazing.

1707

That’s kind of my point though, that a lot of these “supremely unique” features are actually fairly common in an incredibly old & large universe. You can point your telescope in any direction & capture countless extremely rare events.

Comparing local observations to the cosmic scale is like comparing human history to geological deep time. You have to completely change your intuitions.

1708

We’re here because the environment happened to be right for us—not the other way around. If some of those “coincidences” never occurred, we wouldn’t be here to call them coincidences in the first place. It couldn’t be any other way, I guess is what I’m trying to say. It’s not like we’d be here right now arguing about this if every 10,000 years a meteor wiped the planet clean.

Also, a divinely influenced Earth could easily be a much nicer place.

I sense this thread could become a multi page argument about the Fermi Paradox real quick.

1709

Patience. It’s also a religious virtue ;)

We are so small (on the cosmological scale), we are so primitive (not even managed to get it together to colonize another planetary body yet), we are so backwards (likely to destroy our world and human life before we make it off world). Yet we are also incredible, full of potential and with endless future possibilities…if we can somehow avoid our own self-destruction.

So we need to be patient, we need to become more wise, we need to ‘love’ more and ‘hate’ less; and we will find a galaxy and universe teeming with all kinds of life, and maybe one day far in the future we will actually get to meet God…and apologize for taking so long?

1710

And to get back on track :)

‘Lawmakers want NASA to pursue Mars helicopter, Europa lander, more’:

1711

‘MACHOs make a return with gravitational wave discovery’:

cool!

1712

SpaceX goes for 3 in a row for landing their 1st stage in another Geocentric satellite launch. This will be another difficult landing having to go from 5600/KM to zero in few seconds.

The production value of their launch webcast also continue to improve
http://www.spacex.com/webcast

1713

And they did 3rd time in a row. Spacex making rocket science look easy.

1714

Here’s a “highlight reel” of the latest landing right from the rockets point of view. Pretty freaking cool.

1715

Is that footage real-time?

Edit - Nevermind

Sped up video of the Falcon 9 first-stage landing during the THAICOM 8 mission on May 27, 2016

1716

‘Mars makes closest approach to Earth for 11 years’:

Time to get those telescopes out :) I had noticed it in the night sky this last week or so, with the naked eye it has that red shine to indicate it was Mars and not just another star in the sky.

1717

Unlikely to be able to notice unless the cloud cover clears.

1718

We can live in hope :)

‘Universe is expanding up to 9% faster than we thought, say scientists’:

The universe is expanding faster than previously believed – a discovery that could test part of Albert Einstein’s theory of relativity, a pillar of cosmology that has withstood challenges for a century.

Nasa and the European Space Agency jointly announced the universe is expanding 5% to 9% faster than predicted, a finding they reached after using the Hubble space telescope to measure the distance to stars in 19 galaxies beyond the Milky Way.

The rate of expansion did not match predictions based on measurements of radiation left over from the Big Bang that gave rise to the known universe 13.8bn years ago.

1719

‘Low gravity and high radiation: Would humans remain human on Mars?’:

I would have loved for this to be a multipage article, but sadly it is just the one.

1720

Please don’t bust the way it may be reconstituted or not real colours (or maybe just some dust on a lens, for all I know).

1721

Turns out we have a new moon. Sort of: it’s an asteroid that’s been orbiting the Earth for about a century or so, never getting closer than 14 million km.

I blame Obama’s immigration policies. We can’t build the interplanetary Wall (that Venus will pay for!) fast enough.