NASA's Roman Space Telescope will see at least 100 times more sky at once than Hubble and James Webb, helping scientists study invisible dark matter, dark energy and search for thousands of exoplanets

NASA’s Nancy Grace Roman Space Telescope has begun its journey into space after launching aboard a SpaceX Falcon Heavy rocket on August 30. The spacecraft lifted off at 7:26 a.m. EDT from Launch Complex 39A at NASA’s Kennedy Space Center in Florida and separated from the rocket’s second stage about 31 minutes later.

Roman will now travel towards the Sun-Earth Lagrange Point 2, roughly one million miles from Earth, where it will begin preparing for its five-year science mission. Scientists expect the observatory to change how they study some of the biggest unanswered questions about the universe.

Roman will see a much bigger part of the sky

Roman’s biggest advantage comes from its unusually wide field of view. Its primary mirror measures 2.4 metres across, similar in size to Hubble’s, but its Wide Field Instrument can capture an area of sky at least 100 times larger than Hubble can see at once.

That difference will allow Roman to survey enormous stretches of the universe instead of focusing on relatively small sections. NASA expects the telescope to measure light from as many as a billion galaxies during its mission, producing an enormous amount of data for astronomers.

Hubble and James Webb can examine individual galaxies, stars and other objects in remarkable detail. Roman will take a different approach by repeatedly scanning huge areas and looking for patterns across billions of cosmic objects.

It will look for the invisible matter shaping the universe

One of Roman’s major goals involves dark matter, a mysterious substance that scientists cannot directly see.

Dark matter does not emit, absorb or reflect light like ordinary matter. Scientists instead detect its influence through gravity, including the way its gravity bends light from distant galaxies.

Roman will use this effect, known as gravitational lensing, to create detailed maps of how matter is distributed across the universe. By studying how galaxies appear distorted by intervening matter, scientists can work out where large concentrations of invisible dark matter exist.

These observations could help researchers understand how galaxies and larger cosmic structures formed and evolved over billions of years.

Roman will investigate dark energy

The telescope will also tackle another major cosmic mystery, dark energy.

Scientists know that the expansion of the universe has accelerated over time, but they still do not know exactly what drives that acceleration. Roman will survey huge populations of galaxies and cosmic structures to track how the universe expanded through different periods of its history.

Those observations could help scientists determine whether dark energy behaves like a constant feature of the universe or changes over time. Either result could provide important clues about the fundamental physics governing the cosmos.

The telescope will also search for thousands of exoplanets

Roman will not limit its mission to distant galaxies and cosmology. It will also search for planets outside our solar system.

The observatory will monitor enormous numbers of stars and use gravitational microlensing to detect planets. When the gravity of a foreground star bends and magnifies light from a more distant star, a planet orbiting the foreground star can create a brief additional change in that light.

NASA expects Roman’s microlensing survey to monitor around 100 million stars and discover roughly 2,500 planets.

The telescope also carries a Coronagraph Instrument, which will block some of the glare from stars and demonstrate technology that could help scientists directly study planets and planet-forming discs around other stars.

Roman will work alongside Hubble and James Webb

Roman will not replace Hubble or James Webb. Instead, the three observatories will give scientists different ways to study the universe.

Roman will scan enormous areas and identify galaxies, planets and other objects that deserve closer attention. Scientists can then use Hubble or Webb to examine selected targets in much greater detail.

This combination could prove particularly useful for studying rare cosmic events. Roman’s huge surveys can identify unusual objects across vast areas of sky, while other telescopes can zoom in on the most interesting discoveries.

NASA says Roman’s wide field of view and rapid survey capabilities will allow it to study billions of galaxies, investigate planets beyond our solar system and examine objects ranging from nearby cosmic bodies to galaxies near the edge of the observable universe.

A new way of looking at the universe

Roman’s importance will not simply come from producing bigger or sharper space images. Its strength lies in how much of the universe it can examine at once.

The telescope will combine a wide field of view with infrared observations to survey huge cosmic populations, map invisible dark matter, investigate the expansion of the universe and search for planets that other methods may miss.

With the spacecraft now on its way to its final orbit, scientists will spend the coming months preparing its instruments before Roman begins its major surveys. Its first scientific results could give researchers an unprecedented view of how galaxies, planets and the universe itself have changed across cosmic time.