Houston, we are not alone..

[Manfred Belheim]

Do you really want an explanation of this or are you on a soap box?

Well I'd be intrigued as to what explanation you might provide.

 

[Lexicus]

A hypothesis is a possible explanation for something that can be tested, indeed the point of it is to be tested. "There's almost certainly aliens out there" doesn't explain anything and is just a claim with no evidence. Hopefully it'll be possible to test it in the future, but it doesn't appear to be stated as if that's what it's for.

What distinguishes a hypothesis is testability, not whether it's a positive claim. A hypothesis is always a positive claim in the sense of being a proposition.

 

[Manfred Belheim]

I don't see how a proposition is a positive claim.

But I guess this explains why when I say that it's possible that someone might be lying, you read that as me saying they're definitely lying

 

[Lexicus]

prop·o·si·tion
ˌpräpəˈziSH(ə)n/
noun

1. 1.
   a statement or assertion that expresses a judgment or opinion.

 

[Broken_Erika]

Must.....Resist....Urge....To....Aw Screw it!
Houston. We have a Proposition!

 

[uppi]

I agree, I'm just pointing out that we don't have a huge body of evidence that points either way. I'm kind of hoping @uppi knows what's good here. And like I was saying before, the line between comet and asteroid has been sufficiently muddied by recent observations that it isn't always a particularly useful distinction.

I am no expert on this, but there isn't much data on the composition of trans-neptunian objects to constrain theories much. There are a few spectral measurements, some albedo and color measurements and not much else. Exactly one object has been visited by a space probe. The New Horizons flyby of another object in one year will hopefully be another good dataset that will kill some theories, but that still won't be enough to make general statements.

For the Oort cloud it is even worse, because there hasn't been any observation of an Oort cloud object so far. It is dangerous to draw too many conclusions from measurements of objects theorized to have been scattered from there, because those objects might have been altered by multiple passes though the solar system.

 

[Berzerker]

I think comets are primarily chunks of a water rich planet (crust and upper mantle) blasted into space during impacts. Imagine what the Earth was like during the late heavy bombardment 4 bya, objects several hundred kms wide slamming into the ocean. That should have produced a bunch of smaller rocks surrounded by ice flying around...and thats what we see. I dont believe the Oort Cloud is real, I think it was invented to explain comets.

 

[EgonSpengler]

The Washington Post, 20 Dec 2017 - NASA advances missions to land a flying robot on Titan or snatch a piece of the comet

NASA's newest mission will either land a quadcopter-like spacecraft on the surface of Saturn's moon Titan or collect a sample from the nucleus of a comet.

The two proposals were selected from a group of 12 submitted to the New Frontiers program, which supports mid-level planetary science missions.

The first, called Dragonfly, would be an unprecedented project to send a flying robot to an alien moon.

[...]

The Comet Astrobiology Exploration SAmple Return, or CAESAR, mission would circle back to the comet 67P/Churyumov-Gerasimenko, which was visited by the European Space Agency's Rosetta spacecraft from 2014 to 2016. After rendezvousing with the Mount Fuji-size space rock, CAESAR would suck up a sample from its surface and send it back to Earth[...]

Wait just gosh-darned minute. These people want to bring back a piece of a comet?! Haven't they seen The Thing, or Lifeforce, or anything?

 

[hobbsyoyo]

I'm really hoping the quadcopter missions gets selected. I find Titan way more interesting than comets and we need to try more daring missions to expand the envelope. Comet chasing is a daring mission but the essential elements have all been done before. This actually gives it an advantage in that it is a more conservative mission with less risk.
Space is all about managing risk.

 

[Lexicus]

Titan is probably the most interesting Solar System body besides Earth. Enceladus is another place we should send some kind of mission to in the near future.

 

[Manfred Belheim]

prop·o·si·tion
ˌpräpəˈziSH(ə)n/
noun

1. 1.
   a statement or assertion that expresses a judgment or opinion.

I love how this instantly devolved into anal semantics when you know exactly what I'm actually saying.

 

[Lexicus]

I love how this instantly devolved into anal semantics when you know exactly what I'm actually saying.

"Anal semantics" is me supplying a definition of a word that demonstrates how I was using it? I had just assumed we were on a philosophical plane and that you had some knowledge of how 'proposition' is treated in philosophy. I guess those assumptions were wrong.
But in any case, in scientific epistemology a hypothesis is certainly a proposition, ie, a positive, testable claim. It's not necessarily a proposition anyone is invested in, though of course scientists do often tend to get quite invested, emotionally, professionally, what have you, in their pet hypotheses.

 

[Berzerker]

I'm more interested in that asteroid with the exposed iron-nickel core... I think its a left over from the collisions suffered by the proto-Earth ~4bya

 

[EgonSpengler]

I'm really hoping the quadcopter missions gets selected.

Me too.

Titan is probably the most interesting Solar System body besides Earth. Enceladus is another place we should send some kind of mission to in the near future.

From the same article:

Other New Frontiers proposals included missions to study Saturn, Venus or the asteroids around Jupiter, or probe another of Saturn's moons, Enceladus. Two of those proposals were also selected for further technological development: the Enceladus Life Finder, which would look for markers of biological activity in the geyser plumes shooting out of Saturn's moon, and the Venus In situ Composition Investigations, which would be the first NASA spacecraft to conduct in-depth exploration of Venus in almost 30 years.

I'm more interested in that asteroid with the exposed iron-nickel core... I think its a left over from the collisions suffered by the proto-Earth ~4bya

They mentioned "Bennu." I don't know if that's the same one you're talking about.

NASA has three New Frontiers missions already in flight: New Horizons, which flew past Pluto in 2015; and Juno, which is orbiting Jupiter; as well as OSIRIS REx, a spacecraft en route to the asteroid Bennu that will send back a sample from the rock's surface in September 2023.

 

[Lexicus]

From the same article:

I wanna know what's under that ice, man!

 

[EgonSpengler]

I wanna know what's under that ice, man!

Ever see Europa Report? I can't vouch for the science, but it tried to present at least a plausible facade of realistic technology, before it descended into predictable (melo)drama. I thought it was pretty fun, on the whole.

 

[Berzerker]

They mentioned "Bennu." I don't know if that's the same one you're talking about.

16 Psyche... I think its already on NASA's wish list

https://en.wikipedia.org/wiki/16_Psyche

 

[Manfred Belheim]

It's not necessarily a proposition anyone is invested in

This is the whole point of what I was saying and why I don't regard "there must be life out there" as a hypothesis, or at least why that's definitely not the best word to describe it. It's just a statement of belief, not really much of a hypothesis. But getting into a debate about how wide a range of ideas the word "hypothesis" encompasses is completely secondary.

 

[warpus]

It'd be really really really really really weird if the only life in the universe was on Earth and that's it.

 

[Lexicus]

This is the whole point of what I was saying and why I don't regard "there must be life out there" as a hypothesis, or at least why that's definitely not the best word to describe it. It's just a statement of belief, not really much of a hypothesis. But getting into a debate about how wide a range of ideas the word "hypothesis" encompasses is completely secondary.

It's odd, because I would think that actually the first and most important task if we're talking about whether a something is a hypothesis, is to determine what a hypothesis is. When the word is used in the scientific rather than the colloquial sense, it refers to a testable proposition.

In any case, the statement in question is not a hypothesis because it isn't testable. What differentiates "hypotheses" from the larger set of "propositions" is whether the proposition entails specific conditions to test for that could give us a result that definitely disproves the proposition. Some propositions (e.g, "the universe was intelligently designed") are unfalsifiable in principle, while others are only unfalsifiable given our current level of technology, theoretical understanding, etc.