From the early designs of astronomer Ibn al-Haytham
and Italian astronomer Galileo Galilei to the Hubble telescope and large radio
and infrared ground based telescopes, the history of the telescope has been
long, complex, and full of breakthroughs. Now new designs are aiming to
push the limits of telescopes beyond their capabilities and let them see
literally farther back in time.
Telescopes in their many forms detect electromagnetic radiation, which was
produced by celestial
bodies hundreds of millions, if not billions of years ago. The older
the radiation, the more it is scattered across the universe in many directions,
and thus the fainter it will appear. Thus, in order to pick up older
stuff the basic rule of thumb is the more power, the better.
Also valuable is implementing different telescope designs to
catch different types of electromagnetic radiation, as some celestial bodies
are prone to emit more of a certain type of ray, i.e. gamma rays or
infrared. Large-scale telescope designs generally fall into three
categories: reflecting telescopes (includes infrared and visible light
designs), radio telescopes, and high-frequency (gamma and X-ray) telescopes.
Some exciting new designs are being constructed and worked on that promise to
both enrich the variety of designs and pump of the power from the previous
generation. These designs take advantage of modern computer processing as
well as innovative physical designs. Many of these telescopes are going
to be towering giants, while others will be massive arrays of many smaller telescopes.
One of the new "young gun" telescopes is the James Webb Space Telescope (JWST),
which is scheduled
to launch in 2013 as a replacement to the aging,
yet venerable, Hubble. The telescope will be bigger than the
Hubble, with a tennis court sized sunshield and massive mirror (6.5 m in
diameter) that will unfold, once the telescope reaches its intended L2
orbit. The telescope is infrared optimized, but also offers strong
capabilities in the visual light range.
Meanwhile, smaller radio telescopes are combining their powers to form a
massively powerful network, which should have record setting resolution and
sensitivity when finished. The network combines telescopes across three
continents. It will combine the Atacam
Large Millimeter/Submillimeter Array (ALCA), located in Chile; the LOFAR network in Europe; and the Square Kilometer Array (SKA),
which is planned to be constructed in either Africa or Australia.
Finally, there are new designs for singular Extremely Large Telescope
(telescopes with dishes bigger than 20m in diameter) that should be under
construction soon. There are ten active ELT projects worldwide; none are
fully complete yet. However, Europe is forging ahead strongly, looking to
implement its E-ELT, the European Extremely Large
Telescope. The E-ELT will have a dish size of 40m and thanks to a 57M
€ grant from the European Union, will begin construction within three years.
These new telescope designs promises to help mankind see back to the start of
the reionization period. The reionization period is an important
cosmological event which occurred approximately 13 billion years ago.
While the early universe was hot and ionized, after cooling, protons and
electrons paired up into neutral hydrogen. The neutral hydrogen emitted
little light, despite being around 3,000K. The universe went largely
dark, then for millions of years. Then, hydrogen collapsed due to the
weight of gravity and began to form stars which reionized, producing visible
light. The period in which visible light began to be produced again is
called the reionization period. While no current telescopes have the
power to detect the faint traces from this period, these new designs hope to
begin to approach it as they travel back through time.
Forging ahead with these designs is a tremendously ambitious undertaking, but
one which will ultimately benefit all of mankind with a richer understanding of
our universe. The designs will require enormous funds and international
but the great deal of support they are receiving promises to make these dreams
a reality. It should be an exciting next decade for the cosmology and