Hubble Space Telescope

Discussion in 'Hobbies & The Great Indoors' started by hobbit, Oct 31, 2007.

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  1. The HST has an interesting site and provides a regular newsletter . Today the NL has a photo of two galaxies performing a ritual that will probably result in one consuming the other . Makes the local cup final look a bit ordinary eh ! Breath-taking

  2. Glad it's not this galaxy! That would surely bugger the Stock markets and raise the price of oil.
  3. Consider your stock markets buggered. So what if its 3 billion years away, $128 a barrel sound ok?


    We live in the Milky Way Galaxy, a collection of gas, dust, and hundreds of billions of stars. About two million light years (20 billion billion kilometers) away lies the Andromeda Galaxy, a spiral galaxy similar in size and shape to our Milky Way. Current measurements suggest that, in about three billion years, the Milky Way and Andromeda galaxies may collide. What will happen? The stars in the galaxies, our Sun included, will probably not hit each other, but the galaxies' mutual gravity will probably pull, twist, and distort them until, about a billion years later, a new elliptical-shaped galaxy is born.
  4. Puts everything else into perspective doesn't it. I've always suspected that I was irrelevant in the grand scheme of things - now I know it!
  5. Pun intended?
  6. Yes, sorry about that
  7. I have had always found it amusing that the so called experts that pop up now and then to tell us no other intelligent? life form exists in the universe.

    And amusing that they call the human species on this planet intelligent!! while tallking on the F------ mobile phone while I am backpacking down a country lane :threaten: .

    I miss my Charlie G.
  8. chieftiff

    chieftiff War Hero Moderator

    There are 2 (probably) at least in our Galaxy.

    Taken from Wiki and latest estimates of the values for Drake's equation.

    This section attempts to list best current estimates for the parameters of the Drake equation.

    R* = the rate of star creation in our galaxy

    Estimated by Drake as 10/year. Latest calculations from NASA and the European Space Agency indicates that the current rate of star formation in our galaxy is about 6 per year.[2]
    fp = the fraction of those stars which have planets

    Estimated by Drake as 0.5. It is now known from modern planet searches that at least 10% of sunlike stars have planets, and the true proportion may be much higher, since only planets gas-giant size and larger can be detected with current technology.[3]
    ne = the average number of planets (satellites may perhaps sometimes be just as good candidates) which can potentially support life per star that has planets

    Estimated by Drake as 2. The same paper by Marcy, et al.[3] notes that most of the observed planets have very eccentric orbits, or orbit very close to the sun where the temperature is too high for earth-like life. However, several planetary systems that look more solar-system-like are known, such as HD 70642, HD 154345, or Gliese 849. These may well have smaller, as yet unseen, earth sized planets in their habitable zones.
    On the other hand, in recent years, the Rare Earth hypothesis, which posits that conditions for intelligent life are quite rare, has advanced a set of arguments based on the Drake equation that the number of planets or satellites that could support life is small, and quite possibly limited to Earth alone; in this case, the estimate of ne would be infinitesimal.
    fl = the fraction of the above which actually go on to develop life

    Estimated by Drake as 1.
    In 2002, Charles H. Lineweaver and Tamara M. Davis (at the University of New South Wales and the Australian Centre for Astrobiology) estimated fl as > 0.13 on planets that have existed for at least one billion years using a statistical argument based on the length of time life took to evolve on Earth. Lineweaver has also determined that about 10% of star systems in the Galaxy are hospitable to life, by having heavy elements, being far from supernovae and being stable themselves for sufficient time.[4]
    fi = the fraction of the above which actually go on to develop intelligent life

    Estimated by Drake as 0.01.
    Some estimate[citation needed] that solar systems in galactic orbits with radiation exposure as low as Earth's solar system may be more than 100,000 times rarer, however, giving a value of fi = 1×10-7.
    fc = the fraction of the above which are willing and able to communicate

    Estimated by Drake as 0.01.
    L = the expected lifetime of such a civilization for the period that it can communicate across interstellar space.

    Estimated by Drake as 10,000 years.
    In an article in Scientific American, Michael Shermer estimated L as 420 years, based on compiling the durations of sixty historical civilizations. Using twenty-eight civilizations more recent than the Roman Empire he calculates a figure of 304 years for "modern" civilizations. It could also be argued from Michael Shermer's results that the fall of most of these civilizations was followed by later civilizations which carried on the technologies, so its doubtful that they are separate civilizations in the context of the Drake equation. Furthermore since none could communicate over interstellar space, the value of L here could also be argued to be zero.
    The value of L can be estimated from the lifetime of our current civilization from the advent of radio astronomy in 1938 (dated from Grote Reber's parabolic dish radio telescope) to the current date. In 2007, this gives an L of 69 years. However such an assumption would be erroneous. 69 for the value of L would be an artificial minimum based on Earth's broadcasting history to date and would make unlikely the possibility of other civilizations existing. 10,000 for L is still the most popular estimate
    Values based on the above estimates,

    R* = 6/year, fp = 0.5, ne = 2, fl = 0.33, fi = 0.01, fc = 0.01, and L = 10000 years
    result in

    N = 6 × 0.5 × 2 × 0.33 × 0.01 × 0.01 × 10000 = 2

    It is worth noting that the uncertainty in the revised equation is determined primarily by the last 3 factors, fi, fc, and L. If any of these are far smaller than assumed above, as some have argued, then the average number of civilizations willing to communicate may be much less than one. On the other hand non-communicative (possibly xenophobic) civilizations could number in the hundreds, expansionistic civilizations that do not communicate could nontheless eventually come into contact with our own species especially if expansion increases L.

  9. Sorry Chieftiff,

    Whilst the argument you give above is impressive, we all know that there are lots of other intelligent life form bearing planets - we've all seen them on Star Trek, Star Wars etc. And nearly always in colour, so it must be true.
  10. I always thought this one, , reported last April looked promising.

  11. And they're always green, with a cracking set and a furry bikini, and gagging to get it on behind the purple rock with dashing space captains. :thumright:

    Besides which, ChiefT, care to estimate the odds of us being the ONLY sentient life in the universe? I mean, Drake takes care of all the single cellular stuff on Mars and all, but really, you dont need a Taylor approximation to know that somewhere out there, Slartibardfast awaits.......
  12. always PoL??? Hmm your definition of eternity and mine must be quite different ... ;) perhaps there is an anomaly in the space-time continuum, somewhere roundabout Chippenham possibly :w00t:
  13. the bloke in the bike shop did it 'ages' ago :)
  14. IF
    You are in a space ship travelling at nine tenths the speed of light towards another space ship travelling at nine tenths the speed of light towards you. Then what is the closing speed of both spacecraft considering that nothing can travel faster than the speed of light! :ufo:
  15. I submit Trowbridge as a better example of incongruity :thumright:
  16. Seaweed

    Seaweed War Hero Book Reviewer

    With regard to other life-forms, with 0.25 quintillion stars(think that's the last figure I saw) the probability of earth's history having repeated itself somewhere seems quite high! Let us humbly remember that we have only been a species for a dogwatch compared to the 13.7 billion years age of the universe or the 3.5 billion of the solar system, have only farmed for about 9000 years, had writing for about half that (Cadmus sowing the dragons' teeth!), and didn't create a signal that could possibly have been read from outside the earth until a century ago.

    (Of course more knowledgeable people may like to fine tune these numbers but I doubt they are far out).

    So: two thoughts:

    Given the rate of increase of our rate of technological development, what sort of tools may be at our disposal in (say) a couple of centuries' time?

    And if we do ever receive an apparently intelligent signal from elsewhere in space, what are the chances that the 'people' that sent it are very long gone?

    As it is, there do seem to be physical criteria that are prerequisites for 'intelligent' life to flourish into technology: for instance the control grip we have due to our opposable thumbs as well as a power grip, the capacity to comprehend and communicate abstractions, our ability to flourish across a wide range of climate and food supply, our physical ability to run, swim, jump, balance etc; our long period of childhood and learning ..etc etc - contributions welcome.
  17. The frequency of hydrogen is 22hz and the most common element in the universe. The SETI people tune in to that because intelligent civilisations would figure that if they know the frequency of hydrogen then other higher civilisations would as well and transmit on that frequency. I've tried but my DAB radio!
    With so much hydrogen around it's just as well that space is empty. Actually if there was oxygen about in enough quantity then space would be one great big blob of water!
    last one in is a girly!

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