There are not enough adjectives in the human language to
describe how immensely, inconceivably, indescribably vast the universe is. So
how can we expect to convey the beauty of the universe to those without the
time to dedicate their life to such pursuits if it requires us to warp our brains to succeed?
Why do I bring up this mind-warping task? Because that
is exactly what I had to do when I started working on my PhD. How could I
expect myself to study the universe without a true sense of the scale of it
all, and most importantly how could I do this without giving myself a planet
sized headache.
I was recently at the Rose Center for Earth and Space in
Manhattan, just a week before Sandy hit. In the center of the Rose Center is
the Hayden planetarium, an 87 foot diameter (23 meter) sphere suspended in the
center of a giant glass cube that makes up the fascade of the building looking
in from West 81st street. With the sphere as the central point the
exhibits are displayed around and below its rotund shell. One of these exhibits
is The Scales of the Universe, a 400 foot walkway around the glass edge of the
cube surrounding the Hayden Sphere. The
exhibit uses the Hayden sphere to take you on a journey from the smallest
atomic particle to the expanse of the universe giving you a physical scale to
wrap your mind around. Even then, with it placed in front of you the ability to
visualize the 87 foot sphere as a raindrop or an entire galaxy requires some
imagination.
Over the past year I have been studying exoplanets and their
atmospheres and desperately attempting to bring them down to an imaginable
scale. I am currently looking at the hot Jupiter HAT-P-1b using the Hubble
Space Telescope. The term hot Jupiter means that it is a very large planet
orbiting very close to its parent star which when given the numbers floats
solidly in the realm of the unimaginable. So where do you begin? Well I start
with the Earth. How many times the size of the Earth is a hot Jupiter sized planet?
Jupiter is in-fact just over 11 times the radius of the Earth, but HAT-P-1b is
1.225 times the radius of Jupiter; that is a further 2 ½ Earths. So having
dealt with the size we now have to take a look at the orbital distance from its
star. This is where the mind starts to boggle and we have to make our way in
towards the center of our solar system to the closest planet orbiting our Sun,
Mercury. Mercury’s orbit is almost 3 times closer to the Sun as the Earth,
giving it a maximum surface temperature of 700 degrees, but we are not quite
there yet. To get to the orbit of HAT-P-1b we have to go 8 times closer still
at an orbit 95% closer to the Sun than the Earth. To draw it on a landscape A4
piece of paper the Earth would be a the size of a full stop at one end with
HAT-P-1b a 1.5cm circle just 14mm away from the other end of the page that
marks the surface of the Star; and you wouldn’t even be able to see the dot
that would represent Mercury 11cm safely away from the star. If you look at the image below there is a scaled picture showing the size of HAT-P-1b in relation
to the Earth and its orbit in relation to that of the Earth and Mercury with a
zoom in needed on the orbit of HAT-P-1b. This shows just how close hot Jupiters are to their host star and helps explain the extremely hot environments detected for these exoplanets ~1500 K.
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| Total Solar Eclipse (c) NASA |
Nature offers us a unique opportunity to witness how scale
can really put things in perspective via a remarkable coincidence, the solar
eclipse. This occurs when the moon passes directly between us and the sun
blocking out its light. The Sun is 400 times the diameter of the moon and is
400 times as far away meaning that during a total eclipse the moon fits
perfectly over the disc of the sun revealing the shining corona of its extended
atmosphere. It is the equivalent of a pea orbiting a grape blocking out the
view of a human sized sphere over a block away.
So with a pinch of imagination and a tiny bit of patience
the universe can be broken down to the scale of the world around us, where
recognition and reasoning reside.
MORE...
There are so many different 'The Scale of the Universe' websites out there so if you are interested I have listed a few below.
Also if you are ever in the area make sure you check out The Rose Center for Earth and Space on W 81st, Manhattan, NYC or the Smithsonian Air and Space museum on the National Mall in Washington D.C
