Session 3 of #Humanists2021 is go – featuring astrophysicists @SteveSmartt & @Liv_Boeree. The talk is on humanity's place in the universe – a perpetually fascinating subject. We're excited to hear @SteveSmart's insights into the science! 
@SteveSmartt @Liv_Boeree @stevesmart As humanists, creation myths no longer satisfy our need to explain the world, says Stephen. We look to the evidence and the science – which is constantly progressing forwards, he says, as he covers the history of astronomy all the way back to the Enlightenment.
But we essentially do the same thing as we did in the Enlightenment. We observe the universe to the best of our ability. From Galileo to super-powered NASA telescopes – the fundamental scientific principles remain.
Pictured: 10,000 galaxies. It's the deepest exposure of the sky ever taken. It's called Hubble Ultra-Deep Field. The photo was assembled by combining 10 yrs of NASA Hubble Space Telescope photographs taken of a patch of sky.
Mind blowing: @SteveSmartt introduces the The Sloan Digital Sky Survey, which portrays a very real 'slice of the universe'. It's the most detailed three-dimensional maps of the Universe ever made.
@SteveSmartt introduces redshift: an increase in the wavelength, & corresponding decrease in the frequency and photon energy. Objects with more redshift are further away. We've been measuring this for over 100 years and it gives us an idea of how fast the universe is expanding.
The last 100 years has seen a revolution in how we see the universe. Visible optical light is a very small window to see through the universe through. Today, we have mapped out the sky by looking through different windows (wavelengths).
This however, is one of the most peculiar wavelengths, and it's the strongest evidence for the big bang. The cosmic microwave background is electromagnetic radiation which is a remnant from an early stage of the universe, also known as relic radiation.
A great talk on our cosmic origins! Thank you @SteveSmartt. As with many of our talks, we've only just scratched the surface, but it's astounding to think how humanity has been able to reach these conclusions.
What philosophical implications does the rarity of 'Earth-like' planets have? asks @Liv_Boeree. @SteveSmartt responds: 'It gives us an impetus to take care of this planet, this precious place.'
If you can have one questioned answered, what would it be? asks @Liv_Boeree, @SteveSmartt responds: 'I'd have the question of "What is dark matter?" answered. It's bothered everyone for such a long period of time! And, I suspect it will revolutionise physics.'
Q&A: Into what place or space are the galaxies expanding to? A great question! Stephen gives the 'expanding balloon' analogy. 👇
phys.org/news/2013-11-u…
phys.org/news/2013-11-u…
Q&A: Do you believe in time travel? 'Not for beings like us, but it might be possible for very small particles. Stephen responds with the theory of Quantum Entanglement. @SteveSmartt will be answering #Humanists2021 questions via twitter! Thank you!
wired.com/2011/01/timeli….
wired.com/2011/01/timeli….
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