Drakes Equation

[Deepwater6]

http://www.bbc.com/future/story/20120821-how-many-alien-worlds-exist

 

Has there been any new equations that hone much sharper and give us a more defined idea than this famous one? We certainly have more insight than we did in 1961.   
 

[sman]

Wikipedia’s article on the subject includes some current information and concludes:

Inserting these current estimates into the original equation [… ] results in the range of N being from a low of 2 to a high of 280,000,000. As study of the concepts has gone forth, the range has increased at both the minimum and maximum ends.

…buttressing the criticism, I feel, that the thing is just meaningless.

 

My personal criticism of the Drake Equation is more subtle: Which terms should be multiplied? Anything we can think of? This limits the equation by our imagination. Humans are exceptional at dealing with available data – but dismal when it comes to dealing with unavailable data. For instance, it may be obvious that … “the fraction of the above that release detectable signs of their existence into space” (or the fraction of civilizations that develop radio astronomy) should be a term in the equation, but it’s not so obvious that a term like “the fraction of the above that should so much as care about any of this” should be included. IMHO, the omission of this term – the assumption that we don’t need it – is audacious and anthropocentric.

 

What else are we missing? The fact that I can't think of anything doesn't mean there isn't anything.

 

It’s fun to think about these things, but it’s hard to know if we are not simply lost in the realm of fantasy. One trouble is in knowing which questions are practical. Estimating the number of alien civilizations in the universe –something the diagram indicates - is an exercise that returns an abstraction of zero utility. Limiting ourselves to our own galaxy – that is, scaling down about 2 billion times - is only slightly better. Most of our galaxy is utterly unreachable. We do not, and perhaps cannot, appreciate the distances involved.

 

Additional caution is warranted by a lesson I learned in this thread: an estimation of the number of civilizations in the Milky Way offers no prediction of how they are dispersed - and therefore, whether any one of them is, or ever will be, of any consequence to ours. Conversely, were there only one other – so, assuming the low estimate of 2 – the chances that our counterparts are thriving at Alpha Centauri (a locale so remarkably close we could visit, or at least send robots and expect hi-def photos within a generation) are the same as anywhere in the galaxy.

[pgrmdave]

Alpha Centauri (a locale so remarkably close we could visit, or at least send robots and expect hi-def photos within a generation)

Alpha Centauri is over 4 light years away. In order to get there in 100 years, a spacecraft would need to be traveling at an average speed of 29,285,202 mph. The fastest spacecraft in history (relative to the sun) traveled at only 157,078 mph. If we wanted to only take a few generations to get there and get pictures, we'd need to quickly build a spacecraft that could last for a century without maintenance, with fuel that would last a century, and travel more than 186 times faster than anything we've ever built before. To do so within a generation would require a space craft that traveled at 1/5 the speed of light. I don't think that "within a generation" is remotely true. More like "within 500-1000 years". And given that the world changes at increasing rates, that would be like the ancient Romans predicting that they would be sending robots to mars and receiving images from there electronically.

[Deepwater6]

http://www.space.com/29205-nasa-alien-life-search-exoplanets-nexss.html

 

Oddly enough this article was on the Space.Com website today.

 

sman, I have to agree, I usually ask friends if they know how distant planets and stars are from us. Some don't know, but many just can't comprehend it, They know there is a big sky and a lot of space up above, but have no idea of our place in it. Multiverse theories aside, If I'm really being honest I'm not sure I can comprehend it either. 

 

pgrmdave, I agree with you as well. Traveling with today's best equipment would not be very productive unless we had to abandon the planet and tried to save some humans. But the question is how long will it take for us to acquire the knowledge to do something like this? You mentioned 500-1000yrs I think it will be much shorter that that. Going from riding horses to riding a space shuttle in a little over a century shows technology leaps humans can make, but think about compounded leaps computers will make for us? Probably self aware shortly. I really do believe they will learn at a unprecedented rate very soon. I'm also a little uneasy about what they will do with that knowledge someday.
 

[Moontanman]

I do not think that travel directly from one star to another is likely, but in the small steps idea of colonising the oort clouds of stars the entire galaxy could be colonised in a just 2.5 million years with technology not much more advanced than our own and certainly with no magical technology. . 

 

Since new estimates seem to indicate that nearly all stars have planets and many have several Earth sized planets and a significant number may even have more than one Earth like planet temperature wise the drake equation is looking like it needs to be updated... 

[CraigD]

I expect that the work of NASA’s NExSS Coalition and similar researchers, and the astronomy that supports them, will find that the first product of the pre-intelligence factors of the Drake Equation, [math]f_p \cdot n_e \cdot f_{\ell}[/math], is large – that is, that there are an astronomical number of planets with complex biological life – but that [math]f_i[/math] is very small – that is, that most biological life never develops human-like intelligence.

 

I think [math]f_c[/math] – the fraction of civilizations that release detectable signs of their existence into space – depends less on those civilizations’ “releasing” technology, and more on our detecting technology. In the 50 years since Frank Drake presented his famous equation – which I don’t take much as a serious statistical expression, but rather as an invitation to discussion – I think most astronomers and exobiologists have been surprised at how far and how fast exoplanetary astronomy has advanced. The 1960s-‘70s assumption that detecting exoplanetary life required it to transmit powerful radio signals is, I think, negated – we can now detect it indirectly via spectroscopy, and may in the near future, be able to detect more directly with high-resolution optical images.

 

While, as we’ve discussed in this and earlier threads like “are we alone”, physical law makes travel to extrasolar planets on timescales sensible to us humans – the months and years we’ve been, for centuries, accustom to spending traveling to place on Earth – impossible, and travel to them at all a daunting technical challenge. We are, however, increasingly able to build larger and more powerful telescopes, the latest and greatest flown in space.

 

In the 1960s and ‘70s, when knowledgeable, thoughtful people imagined discovering extrasolar civilizations, they imagined detecting radio signals with big ground-based radio telescopes, or, more outlandishly, seeing them up close by sending spacecraft to other star systems. Now, I think, a clear and careful analysis of current and likely near-future technology should lead us to imaging detecting them with big space-based optical and infrared telescopes.

 

Communicating with such civilizations – if [math]f_i[/math] is sufficiently large for many to exist, rather than the “rare Earth” hypothesis being correct – could be a simple as writing large glyphs in our planets’ deserts, which we read with our giant space telescopes. This reminds me of early 20th century astronomers’ like Lowell schemes for communicating with the Martians they imagined might be watching earth with telescopes (see “Hello Mars – This is the Earth”, a Smithsonian article about a 1919 magazine article of the same title)

[Moontanman]

Obviously what we really need is a good cheap warp drive.. 

[CraigD]

Obviously what we really need is a good cheap warp drive..

Yeah, but the causality violations would be awfully weird!

 

Writers of space opera just ignored modern physics, then when they, and more importantly, too many of their audience knew enough physics that that approach no longer worked, invented workarounds like warp drive and navigable wormholes to allow space travelers to have about the same lifestyles as terrestrial mariners. Few of the viewing public have learned enough physics to be offended at the lack of causality violations demanded by FTL travel or communication, so space operaists haven’t had to find workarounds for it yet.

 

(my favorite explanation of faster than light communication demanding causality violation, Richard Baker’s Sharp Blue: Relativity, FTL and Causality)

[Moontanman]

Yeah, but the causality violations would be awfully weird!

 

Writers of space opera just ignored modern physics, then when they, and more importantly, too many of their audience knew enough physics that that approach no longer worked, invented workarounds like warp drive and navigable wormholes to allow space travelers to have about the same lifestyles as terrestrial mariners. Few of the viewing public have learned enough physics to be offended at the lack of causality violations demanded by FTL travel or communication, so space operaists haven’t had to find workarounds for it yet.

 

(my favorite explanation of faster than light communication demanding causality violation, Richard Baker’s Sharp Blue: Relativity, FTL and Causality)

 

 

I was under the impression that "warp drive" wouldn't cause causality problems since the spacecraft never actually travels faster than light... 

[pgrmdave]

I was under the impression that "warp drive" wouldn't cause causality problems since the spacecraft never actually travels faster than light... 

The problem is that if it's ftl in any frame of reference then it can be used to send messages back in time in that frame of reference.

[Moontanman]

The problem is that if it's ftl in any frame of reference then it can be used to send messages back in time in that frame of reference.

 

 

How far back in time? what determines how far back in time? 

[pgrmdave]

How far back in time? what determines how far back in time? 

Back in time at all breaks causality.

[Moontanman]

Back in time at all breaks causality.

 

Yes but are we talking about millions of years or such a short time it wouldn't matter from a practical standpoint?