The Science Behind The Thirty Meter Telescope


TMT will be three times as wide, with nine times more area, than the largest existing visible-light telescope in the world. This larger telescope will deliver sharper and deeper images than existing telescopes both on the ground and in space. These gains can only be realized if we correct the blurring effects of the Earth’s atmosphere with special adaptive optics. Maunakea is one of the best sites in the world for using adaptive optics to sharpen images, as the atmosphere over Hawaii is calm, steady, and most often free of clouds and weather. As a result, TMT will likely revolutionize our understanding of the universe and will help to ensure that Hawaii remains the global leader in astronomy.

Capabilities Provide By A Large Diameter Telescope

A large diameter telescope provides two new basic capabilities that are not available with existing ground based telescopes and that cannot be delivered by the small telescopes in space or planned for the future:

  1. Improved spatial resolution, as long as the distorting effects of the Earth’s atmosphere are corrected for with an adaptive optics system; and
  2. Increased sensitivity

Sharper images allow us to see smaller objects and more detail; thus TMT will provide three times better resolution and detail than other telescopes. One example of new science that can be achieved with TMT’s tripled resolution is finding planets around other stars in the “habitable zone,” where the separation between the star and the exoplanet is similar to Earth and that allows for liquid water on the planet’s surface. Many other areas of science that TMT will explore require finer spatial resolution than is currently available. TMT will have a high performance adaptive optics system from day one.

TMT will also deliver a huge increase in sensitivity or image depth, thanks both to the larger area of the telescope and the sharper images. Increased sensitivity will finally allow us to detect the faintest, most distant galaxies and the smallest stars and planets. High sensitivity also means the properties of stars and galaxies are measured more quickly, allowing more objects to be studied and more rare objects to be found. The sensitivity for standard forms of observations is proportional to the telescope’s diameter (D) multiplied by itself 4 times (DxDxDxD). Today, large telescopes are typically 8 meters in diameter; in comparison, the TMT will be 200 times more sensitive, up to 200 times faster or able to detect objects 200 times fainter.

Scientific Areas Enabled With A Larger Telescope

The TMT will be a general-purpose telescope, able to carry out different scientific investigations across many areas of astronomy, planetary science, and physics. The telescope will support a variety of instruments that work at different wavelengths of light (optical or infrared) and take images or spectral measurements. The instruments selected for early operations are versatile in nature.

A few key science areas that TMT will address far better than any existing facility include:

TMT will study very distant “standard candle” supernovae that are magnified by the strong gravity of nearby galaxy clusters. The properties of these supernovae will allow TMT to test competing theories of Dark Energy and to determine how Dark Energy and Dark Matter have governed the evolution of our universe over cosmic time.

The Evolution of the Structures in the Universe

TMT will be able to study the earliest galaxies that formed, when the universe was only a small percentage of its present age; galaxies containing stars comprised of raw materials from the Big Bang. TMT will also extend the studies of the shapes, dynamics, and chemistry of early galaxies – from 5 to 6 billion years ago and further back in time to almost 13 billion years ago, when the very first structures in the universe were forming. TMT will also study individual stars in our local group of galaxies at a volume nearly 100 times larger than currently possible. By resolving and studying these individual stars, we can determine how our Milky Way Galaxy and its nearest neighbors have grown, interacted, and possibly even merged (i.e. captured dwarf galaxies) over the history of the universe.

Super-Massive Black Holes In Galaxies; Their Birth and Their Relationship With Galaxies:

The growth of Super-Massive Black Holes in the centers of galaxies, with masses up to a billion times the mass of the Sun, is closely linked to growth evolution of the host galaxy. TMT’s increased spatial resolution will allow us to weight black holes down to 20 times smaller than is presently possible. This will extend our studies of the link between black holes and their host galaxies back to earlier cosmological times, with more than a 1000-fold increase in the number of systems where black holes can be weighed.

The Formation of Stars and Planets

Presently, the process of star and planet formation, from collapsing clouds of gas and dust, is poorly understood. TMT can provide high fidelity images and spectra at infrared wavelengths of individual stars even in the most crowded parts of the Milky Way and our nearest neighbor galaxies. The greatly expanded range of environments that TMT can probe will allow us to understand how stars and planets, large and small, form under conditions very different from our Sun’s neighborhood.

The Characteristics of Exoplanets and Whether There Is Life Elsewhere in the Universe

We now know most stars have planets around them and Earth-sized or terrestrial planets in the habitable zones of their host stars are common. Space-based and existing ground-based telescopes can barely begin characterizing the highest mass, highest temperature exoplanets, such as hot-Jupiters and lava planets, examples that are very different from the main population. Thirty Meter class telescopes will allow us to study the main population and to answer the important question whether terrestrial exoplanets have atmospheres similar to Earth’s. The study of the atmospheres of earth-like exoplanets can go further by looking for the existence of water and organic molecules, evidence of biological activity, and evidence of extra-terrestrial life in the molecules present in the atmosphere.Note: Regarding spelling of Maunakea, we use the spelling preferred by the UH Hilo Ka Haka ‘ula o Ke‘elikolani College of Hawaiian Language.