Eye spy space
People have been staring at the heavens
since prehistoric times. They measured
the positions of the stars and watched
the movement of the Sun, Moon, and
planets across the sky. But there was a
limit to what could be learned with
the naked eye.
LICK TELESCOPE The James Lick
Telescope is an antique refracting
telescope built in 1888. It is the third
largest example of this type of telescope
in the world. It is in California and is
4,209 ft (1,283 m) above sea level.20TAKE A LOOK
MARS FROM HUBBLE This picture of
Mars was taken with the Hubble Space
Telescope. It shows the southern polar cap, the
orange deserts, and sheets of ice cloud.Optical telescopes can obtain images of far-
away planets and stars. Other telescopes
study the universe by capturing radio
waves, X-rays, and other types of radiation.SPACE
In order to avoid becoming ill
with altitude sickness, people
visiting mountaintop observatories,
such as Keck I and II, have to stop
and wait halfway up the mountain.
This allows their bodies to adapt to
the decrease in oxygen in the air.7 /^7