A schematic history of the universe, with time running left to right from the Big Bang to today. (Credit: NASA Science Team)
Gazing into the vast expanse of the universe, humanity has always pondered its origins, its evolution, and its potential for life beyond our own planet. The Thirty Meter Telescope is designed to answer some of the most profound questions in astronomy:
Cosmic composition: What is the nature and structure of the cosmos? What is dark matter and dark energy?
Galactic dawn: When did the first galaxies arise and how did they subsequently evolve?
Black holes and galaxies: What is the relationship between supermassive black holes and the galaxies they reside in?
Stellar and planetary birth: How do stars and planets form?
Worlds beyond our own: What are the characteristics of planets orbiting other stars?
Extraterrestrial life: Is there life elsewhere in the universe?
Many of the observing programs that will address these questions are outlined in the TMT Detailed Science Case. The Detailed Science Case is organized into science themes, science cases within each theme are developed by the members of the corresponding International International Science Development Teams, one for each science theme:
With its unparalleled sensitivity and precision, TMT will explore the very fabric of the cosmos, shedding light on the invisible forces and components — dark matter and dark energy — that shape our universe. Dark matter, which makes up most of the universe’s mass, can’t be directly observed, but its effects are everywhere. TMT will be able to map these effects in incredible detail, offering clues to the true nature of dark matter: studying substructures and the form of the central concentration in the mass distribution in dwarf galaxies and the structure of dark matter halos that surround galaxies.
The early universe holds some of the greatest mysteries in astronomy, and TMT will be pivotal in uncovering them. One of the most critical periods in cosmic history is the transition from the universe’s Dark Ages to the Epoch of Reionization — when the first galaxies formed and began to illuminate the universe. But how did these early galaxies emerge, and how did they transform the universe from darkness to light?
Supermassive black holes (SMBHs) are now understood to be at the heart of nearly every massive galaxy, including our own Milky Way. These enormous objects — millions to billions of times the mass of the Sun — are closely linked to the evolution of their host galaxies. The feedback or influence on the host galaxy from the SMBH during phases of black hole growth significantly impacts star formation and the gas content of galaxies. TMT’s high-resolution imaging and ultra-deep spectroscopy will revolutionize our understanding of supermassive black holes, from their formation and growth to their dynamic influence on galaxies across cosmic time.
Stars serve as cosmic time capsules, preserving the fossil record of galaxy formation processes. By studying how stars are spread out, how they move, how old they are, and what they are made of, we can learn a lot about how galaxies form and evolve over time. However, much remains a mystery due to the limitations of current telescopes in resolving individual stars and the ability to test theoretical models. TMT will bring unprecedented sensitivity, angular resolution, and astrometric precision to the investigation of stellar populations, allowing astronomers to study how galaxies form and evolve.
The life cycle of stars is intimately connected to the material floating between them — the interstellar medium. Stars are born from this gas and dust, and as they age and die, they enrich it with heavier elements forged in their cores. Understanding this complex relationship requires a detailed picture of how stars evolve, particularly how their mass and the amount of heavy elements they contain influence their lives. TMT observations will address how heavy elements spread inside stars, the evolution of massive stars deficient in metals (like those in the early universe), the formation of small stars in similarly metal-poor environments, and the nature of rare, extremely metal-poor stars. TMT will also help us pin down the relationship between a star's initial mass and what it becomes at the end of its life, how elements are created within stars, and even refine our understanding of the creation of lithium in the Big Bang.
TMT’s tremendous spatial resolution and sensitivity will allow astronomers to resolve individual young stars, even in distant stellar clusters, throughout the Local Group of galaxies and beyond. These observations will reveal how star formation depends on environmental factors, providing critical insights into the physical processes that shape stellar populations and influence galaxy evolution. TMT will use the high-dispersion spectroscopy and coronagraphic imaging and spectroscopy to study the disks around young stars, revealing the conditions that lead to planet formation.
One of the most thrilling scientific quests for TMT is the search for life beyond Earth. In just a few decades, astronomers have discovered thousands of exoplanets — planets orbiting stars beyond our solar system. These discoveries include a wide range of worlds, from hot Jupiters and super-Earths to gas giants and rocky planets. Yet, we are only beginning to explore the potential diversity of exoplanets and the possibilities of life on them. TMT will take the next giant leap in exoplanet science, enabling the full range of planets to be characterized, giving complete context for making detailed investigations of planets in the habitable zones of the nearest stars — regions where conditions may support liquid water and, possibly, life.
TMT will revolutionize our understanding of the solar system, uncovering the fundamental processes that have shaped planets, moons, and other small bodies. Despite advancements in planetary science, many key questions remain unanswered about how our solar system formed and evolved and how its diverse components interact today. TMT’s extraordinary sensitivity, high-resolution imaging, and wide wavelength range will enable complementary studies of solar system objects in unprecedented detail, in ways that space missions cannot.
TMT will be a game-changer in time-domain astronomy, a field that studies cosmic events as they unfold in real-time. These events such as supernovae, gamma-ray bursts, and neutron star mergers or processes such as the growth of supermassive black holes are unpredictable and often fleeting, requiring rapid and precise follow-up observations. TMT, with its adaptive queue and advanced instrument suite, will be perfectly positioned to respond to these targets of opportunity and measure the changing appearance of some of the most enigmatic phenomena in the universe.
