Astrochemists study the chemistry of other planets and stars by working with astronomers and geologists. They analyze the chemistry of atmospheres, elemental makeup of stars and asteroids. This involves studying the chemistry and any organic compounds that may be present on other celestial bodies both near and far, including young galaxies over 10 billion light years away. Much of what we are made of, including over 90% of our mass, originated from stardust created in supernova explosions that dispersed elements across the universe.

1. Emre Baki
Raffles World Academy

2.  Wherever matter is changing, chemists won't
be far behind!
 It's here on Earth, on the Moon, on Mars...
anywhere!
 Astrochemist work with astronomers and
geologists to study the chemistry of other
planets and stars.

3.  Chemistry of atmospheres
 Chemistry and elemental makeup of stars
 Chemistry and elemental makeup of asteroids
(those are easier to study because they come
close to Earth)
 Anything that might be on another body in
the Universe

4.  For thousands of years, Mars looked reddish when
viewed from Earth through telescopes
 Scientists figured out from samples that the rocks
and dust have a high level of iron (Fe). When the
iron oxidizes with any trace oxygen (O) in the
atmosphere, it turns red
 Scientists even believe that there still might be a
frozen layer of water (H2O) beneath the surface of
Mars.
 Every probe send to the planet gives huge amount
of information

5.  Almost every element on Earth was formed at the
heart of a star.
 Stars owe their light to the energy released by nuclear
fusion reactions at their cores.
 These are the very same reactions which created
chemical elements like carbon or iron - the building
blocks which make up the world around us.
 During a supernova, when a massive star explodes at
the end of its life,
 The explosion also disperses the different elements
across the universe, scattering the stardust which
now makes up planets including Earth.
Supernova
remnant. Image
credit: NASA

6.  If we know how many hydrogen atoms are in our
body, then we can say that the rest is stardust.
 Our body is composed of roughly 7x1027 atoms.
 4.2x1027 of them are hydrogen. Remember that
hydrogen is bigbang dust and not stardust.
 This leaves 2.8x1027 atoms of stardust. Thus the
amount of stardust atoms in our body is 40%.
 Most of the hydrogen in our body floats around in
the form of water. The human body is about 60%
water and hydrogen only accounts for 11% of that
water mass.
 We can conclude that 93% of the mass in our body
is stardust. Just think, long ago someone may have
wished upon a star that you are made of.

7.  You don't always have to send a probe.
 Astronomers at NASA's Spitzer Space Telescope have
detected organic compounds in very young galaxies.
 They found polycyclic aromatic hydrocarbons which are
ringed molecules made of hydrogen (H) and carbon (C) in
various arrangements.
 They used an instrument called an infrared spectrometer to
split up the infrared light that Spitzer detects.
 They found peaks in specific wavelengths that told them
organic molecules were present.
 The most amazing fact is that they were studying galaxies
that are 10 billion light years away.

9.  Basically, organic chemists study every
compound that has a carbon (C) atom in it
 Life on Earth is based on carbon compounds
 Other planets may have life based on silicon
(Si) or sulfur (S). Did you know that some
organisms can survive with reactions that
include hydrogen sulfide (H2S) instead of
water (H2O)?
 Scientists are looking at similar organisms at
the bottom of the ocean and in aquatic areas
without oxygen (anoxic)

10.  Deep under the Mediterranean Sea small
animals have been discovered that live their
entire lives without oxygen and surrounded
by ‘poisonous’ sulphides.
2010, The first metazoa living in
permanently anoxic conditions

11.  Encyclopedia.com (Astronomy):
http://www.encyclopedia.com/topic/astrono
my.aspx
 Wikipedia:
http://en.wikipedia.org/wiki/Astrochemistry
 Encyclopædia Britannica (Astronomy):
http://www.britannica.com/EBchecked/topic/
40047/astronomy