A significant problem
for infrared astronomy is that water absorbs infrared radiation
extremely well. This is analogous to why a microwave oven very
quickly heats the cheese on a pizza, but not its crust. Cheese
contains more water and fat than the crust. Water molecules in
the cheese absorb the energy of the microwaves, vibrating and
moving about quickly. The cheese gets hot, finally melting. This
is good for pizza-lovers, but not infrared astronomers.
Even though infrared
radiation can easily travel billions of kilometers through
the universe, it has nearly zero chance of reaching the
surface of the earth, since the water in our atmosphere
quickly absorbs it. Thus, infrared astronomers build their
telescopes on the peaks of high mountains such as a Hawaii
volcano or a high-plateau in the Chilean Andes, launch infrared
observatories into the stratosphere (upper atmosphere) by
balloon, or into space by rocket.
The Canadian infrared astronomy community uses all three
opportunities: the JCMT
is an infrared telescope in Hawaii, which is funded by the
UK, the Netherlands, and Canada. The BLAST
project is an infrared camera on a high altitude balloon.
Also, Canadian astronomers can apply for time on an infrared
space observatory such as Spitzer
or, in the future, Herschel.
