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View Full Version : 60 Billion Habitable Planets in the Milky Way Alone? Astronomers say Yes!



Fraser
2013-Jul-09, 05:50 PM
A new study suggests that the number of habitable exoplanets within the Milky Way alone may reach 60 billion. Previous research performed by a team at Harvard University suggested that there is one Earth-sized planet in the habitable zone of each red dwarf star. But researchers at the University of Chicago and Northwestern University have [...]

More... (http://www.universetoday.com/103379/60-billion-habitable-planets-in-the-milky-way-alone-astronomers-say-yes/)

Selfsim
2013-Jul-09, 10:12 PM
So, each time another factor gets thrown into the model for 'habitability', the numbers of 'habitable' exo-planets increases ...

How is this helping to better constrain the search space for exo-life?

Answer: It isn't!

So, what then is the purpose of the concept of 'habitability'?

It ain't workin', folks its broken!

ASTRO BOY
2013-Jul-09, 11:04 PM
Nice article....
Let's hope enough people read it and realise that the chances of us being alone are very small, and that as a species we are probably not very special at all.
Also it may put a rocket [excuse the pun] up those that distribute the money for space exploration and the continued search for ETL.

Selfsim
2013-Jul-10, 12:10 AM
Say it costs .. I dunno $1000 to search each planet for so-called, atmospheric 'biogenic gases'.

So, that's $60 trillion, ($60 x 1012 .. what does that look like, anyway? (http://www.youtube.com/watch?v=jfBmAyCob3U)), to search the set of (presumably) verified habitable exo-planets, using a test that doesn't provide any assurances that the bulk of the uncertainties can be eliminated ...

Why does this not motivate me?

ASTRO BOY
2013-Jul-10, 12:24 AM
Say it costs .. I dunno … $1000 to search each planet for so-called, atmospheric 'biogenic gases'.

So, that's $60 trillion, ($60 x 1012 .. what does that look like, anyway? (http://www.youtube.com/watch?v=jfBmAyCob3U)), to search the set of (presumably) verified habitable exo-planets, using a test that doesn't provide any assurances that the bulk of the uncertainties can be eliminated ...



Depends on what sort of time frame we spread it over.......


[QUOTE=Selfsim;2144282
Why does this not motivate me?[/QUOTE]



Don't ask me.

Selfsim
2013-Jul-10, 04:38 AM
In the 8.66GHz centred spectrum, it takes SETI about 4.5 hrs searchtime (+/- 2 hours) to complete one search for ETIs, on one parent star region (using the Allen Telescope Array at UofC, I think).

Whereas SETI searches are band-limited searches, targetted exo-atmospheric spectrographic searches are a fundamentallly a different proposition. The Webb Telescope Near Infrared Spectrometer has been designed with a multi-object mode, which uses a complex micro-shutter mechanism, enabling simultaneous observations of ~100 individual objects within a 9 arc-minute field of view (of varying redshifts between 15 and 30). Its ability to see exo-atmospheres however, will be much more limited due to a combination of the technology resolving power (at varying distances), and the transit detection analysis method practicality limitations.

The Kepler team took some 3 years to release the first Kepler data .. they eventually got that down to about a 1 release-per-1.75 year figure. Kepler, I think, can see only about 4.4 million stars total, in its view of view. (Compare this number with the number of 60 billion exoplanets!)

The point here is, that if there are ~60 billion exo-planets to check out, its going to take an enormous amount of resource to gather, process and analyse that data (just to validate this hypothetical prediction!)

I wonder just how far off the mark my ballpark estimate of $1000 per exo-planet figure might be(?) Its looking to be many, many orders of magnitude too little, I think.

ASTRO BOY
2013-Jul-10, 06:20 AM
The point here is, that if there are ~60 billion exo-planets to check out, its going to take an enormous amount of resource to gather, process and analyse that data (just to validate this hypothetical prediction!)

I wonder just how far off the mark my ballpark estimate of $1000 per exo-planet figure might be(?) Its looking to be many, many orders of magnitude too little, I think.



In reality the real point is no matter how far advanced we become, no matter how much advanced technology we are able to harness, no matter even if we achieve the perception of warp speed and FTL travel via space/time warpage. it's going to take an awful long time to explore our galaxy.
And in those time frames, probably approaching thousands and even tens of thousands of years, we most certainly will not have the same or even similar economics we do today, nor will any political idealism of that time be recognised when compared to today.
But given that time, humanity, [and our descendants], will give it a good shot!

One wonders then considering the time frame, and humanity [or our descendants] surviving that time frame, if we'll start focusing our attentions beyond the Milky Way.
Maybe by that time, we could achieve beyond MW travel in partnership with ETI we have met along the way.

Selfsim
2013-Jul-10, 06:58 AM
The Kepler spacecraft data commenced being analysed around Dec 2009. As far as science data collection is concerned, Kepler has been broken since June 2013. (So that's about 2.5 years of effective data gathering). Its design lifetime was originally ~7.5 yrs.

The JWST design lifetime is about the same as Kepler's. (I wonder if we can use the Kepler operational lifetime figure above as a guideline for estimating approx how long the JWST might last?) Anyway, I don't think it'll be able to make the slightest 'dent' in making useful observations of 60 billion exo-planetary atmospheres(?) Well, we know it can't possibly do this by the transit detection method (due to the alignment geometry issue) ..

So, exactly what scientific use is a hypothesis which makes a prediction of:

This effect will be testable with the James Webb Space Telescope. All in all, the Milky Way is likely to be teeming with life.Who is it that is supposed to have said this in the article anyway? Was it only the author ('Shannon Hall'?)

Jens
2013-Jul-10, 09:36 AM
Maybe by that time, we could achieve beyond MW travel in partnership with ETI we have met along the way.

I kind see it this way. Either you can build a warp drive or you can't. If you can't, then we'll probably never get anywhere. If you can, then there are aliens teeming around us and no matter where we go we'll find them.