TMT Construction Proposal - Thirty Meter Telescope

What is the nature and composition of the Universe
Ordinary matter can generally be detected directly, from the light emitted by
stars, from radiation emitted by hot gas in galaxies and clusters, and by
absorption of light from background luminous sources. We can infer the
presence of dark matter from its gravitational attraction, which affects the
motion of galaxies and the propagation of light. In contrast, the gravitational
effect of dark energy is repulsive, manifested by an increase in the rate of
expansion of the Universe. A census of these components reveals the
surprising result that normal matter accounts for only a small fraction of the
composition of the Universe– the rest is dominated by dark energy and dark
matter. Closely related to the question of the composition of the Universe, is its
dynamical history. The inflationary period that produced the observable
Universe is believed to have been driven by a form of dark energy – a scalar
field. Incredibly, the earliest moments of the Big Bang, involving physics on the
smallest scales, can be probed by observations of the large scale structure of
the Universe.
Fig 2-2: Composition of
the Universe.
When did the first galaxies form and how did they evolve
By looking into space to greater and greater distances, we are able, thanks to the finite speed of light, to see
further and further back into the past. To see the very first stars and galaxies we must look over enormous
distances, some 13 billion light years. So far these objects remain beyond the reach of present telescopes. At
lesser distances, moving forward in time, we see galaxies interacting dynamically and forming stars. But it is
not yet clear how this produces the diversity of galaxy types that are seen today.
What is the relationship between black holes and galaxies
There is now overwhelming evidence that black holes exist, and that black holes with as much as a billion times
the mass of the Sun occupy the centers of galaxies. But, we don’t know when or how these supermassive
black holes formed, or how they fit into the overall picture of galaxy formation and evolution.
How do stars and planets form
Stars form within molecular clouds, by a combination of complex physical processes. What determines when
these clouds form stars What determines the masses of these stars What fraction have planetary systems
There are many questions we are just beginning to explore.
What is the nature of extra-solar planets
The exoplanets detected so far are gas giants like Jupiter and Neptune. They were discovered because their
large mass noticeably perturbs the motion of the host star. Surprisingly, many are found very close to their host
star. As the higher temperatures from near proximity would prevent such planets from forming, it seems they
must have migrated inward after first forming at greater distances. We believe that smaller terrestrial planets
exist, but these cannot be detected with present telescopes. Are such planets common Can they survive the
disruption that would result from migration of the massive planets Do they have atmospheres like Earth
Is there life elsewhere in the Universe
If terrestrial planets exist, are conditions conducive to the development of life Each star has a habitable zone,
where a planet would have a surface temperature comparable to Earth’s. If, as expected, exoplanetary systems
have populations of small icy bodies like comets, it is possible that water and organic molecules could have
been delivered to such planets by impacts. If life then develops, it might be detected by signatures of biological
activity in planetary atmospheres.
2.1.3 The required tools
To answer these and many other questions, advances in technology are needed. The greatest progress will
come from combined studies at many different wavelengths using ground and space-based facilities. Several
major new telescopes will begin operation in the next decade, including the James Webb Space Telescope
(JWST) and the Atacama Large Millimeter Array (ALMA). Soon to follow will be the Square Kilometer Array
(SKA). By providing powerful new capabilities at optical, infrared, microwave and radio wavelengths, these
facilities will open new frontiers. Yet they alone will not be sufficient. Much as the resolution of the Hubble
Space Telescope was complemented by the greater light gathering power of the Keck 10-meter telescopes,
these upcoming facilities will require a complementary large-aperture ground-based telescope to provide high
spatial and spectral resolution observations in the optical and infrared. In fact, a revolution in technical
capability now makes ground-based telescopes even more effective. Adaptive optics (AO) systems allow the
largest optical-infrared telescopes on Earth to achieve higher resolution than telescopes in space, which
TMT Construction Proposal 6