March 7 - Launch of Another Space Telescope

nPosted on March 7, 2019

Key Points

First, there was Galileo’s early-1600s telescopes. Even though they were not even as good as today’s super cheap (under $30) amateur scopes, Galileo’s telescopes helped
nrevolutionize astronomy and humanity’s worldview – or, we might say, cosmic view!
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nFor one thing, Galileo’s observations furthered the idea that the Earth was not the center of the universe.
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Above, Saturn as Galileo may have seen it.
He wrote that Saturn seemed to have “ears.”

Below, Jupiter as Galileo may have seen it.
He was able to see Jupiter’s four largest moons.

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Above, what Saturn looks like through a small
modern amateur telescope. You can see that the
“ears” are actually rings.

Below, what Jupiter looks like through a modern
amateur telescope.

nThen there were all the increasingly large, increasingly powerful Earth-based telescopes that improved our view of our galaxy and other galaxies – and that led to the Big Bang Theory.
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nAnd then there was the Hubble Space Telescope. All of a sudden, with a telescope above the Earth’s constantly-moving atmosphere, we had access to amazing photos of beauty and strangeness…
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What’s strange about this photo is that almost everything we see
here – every fuzzy blob and every speck of light – is a far-away
galaxy with maybe 100 billion stars in each and every galaxy!!!

(Actually, galaxies range in size from “small” to gigantic,
with our own Milky Way having about 300 billion stars.)

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nSome other space telescopes include the Chandra X-Ray Observatory (launched in 1999) – which observes soft X-rays –
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n– and the Spitzer Space Telescope (launched in 2003) – which observes infrared radiation.
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nThese telescopes have been important in studying black holes and star-forming regions and more.
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nOn this date in 2009, NASA launched the Kepler Space Telescope in order to discover Earth-size planets orbiting other stars. In nine years of operation (the telescope was retired when its fuel was depleted, in October of 2018), Kepler observed more than half a million stars and detected 2,662 planets.
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nIt’s important to note that the method of data collection meant that Kepler could only discover planets that happen to have orbits we see as edge-on – because as they pass in front of their host stars, we can detect the dimming of the star. If we are looking “down” onto a planetary system and the planet never passes between its sun and our telescope, couldn’t spot it with Kepler.
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When we say “edge on” – we are looking at a stellar
system from a direction which sometimes shows
one or more planets crossing in front of the star, as above.

When we are looking “down” on a stellar system,
we never see planets crossing in front of their star.
It’s as if we are looking at one of those stellar
system diagrams seen below.

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In the same way, spiral galaxies look very different
when seen edge-on (as in the photo above)
or when we look “down” on them (as in the photo below).

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Using the data from Kepler, scientists have been able to estimate around 40 billion rocky Earth-size planets within our galaxy! That counts exoplanets (planets that aren’t in our solar system) that are circling red dwarfs as well as those circling Sun-like stars; the number shrinks to around 11 billion Earth-size exoplanets that are circling Sun-like stars.

Still – 11 billion!! Wow!
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nOf course, these are just estimates based on our current limited data. But if they are accurate, there is a good chance that the nearest rocky Earth-like planet may be only 12 light years away!
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nHere are some exciting artist renditions of landscapes some of these exoplanets may offer:
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nThe next step in space telescopes may be NASA’s James Webb telescope, set to launch in March 2021. I can hardly wait!
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nHere‘s a great short video called “This Is Not What Space Looks Like.”
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nAnd here is a science-based visualization of 500 of the exoplanets discovered before October 2015 (including many gas giants, not just the rocky Earth-like ones) – a pretty cool poster, methinks!
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