Exploring the early universe with NASA's Roman Space Telescope

Researchers in particle physics are trying to determine what happened in the very first second of the universe. The events of the initial instant are vital to issues in particle physics today.
Elma Henshaw
Nancy Grace Roman Space Telescope's element assembly wheel
Nancy Grace Roman Space Telescope's element assembly wheel

NASA's Nancy Grace Roman Space Telescope/Flickr 

Cosmologists extrapolate the universe's present-day expansion backward in time to learn more about the early universe's conditions. According to a popular theory, roughly 13.8 billion years ago, all of the matter and energy in the cosmos was confined to a singularity with infinite temperature and density. The Big Bang states that when the universe was roughly 10-34 of a second old, it experienced an expansion known as inflation. At this time, space burst forth, expanding faster than light.

After this, space continued to expand, although at a slower rate. It is thought that the Higgs field began to operate at around 10-12 seconds after the Big Bang, giving elementary particles mass.

Today, astronomers combine mathematical models with observations to Fobetter understand the universe's history and what occurred in the first moments after the big bang.

This information helps them to determine the nature of the universe—and could even explain how it will eventually end.

Some researchers in particle physics are trying to learn more about what occurred in the very early period of the universe's formation. The events of that initial instant are related to many vital issues in particle physics today.

For around 380,000 years, the universe was still too hot even for light to shine. TInflation'simmense heat and force from inflation generated a dense plasma soup of protons, neutrons, and electrons that scattered light. After this, matter cooled enough to allow atoms to form, generating a transparent, electrically neutral gas. This produced a flash of energy whose traces remained as cosmic background radiation, but as no stars had yet formed, the universe was again in darkness.

It was another 400 million years before the first stars and galaxies began to form.

Scientists have been able to go far back in time to study the early cosmos using large telescopes. What they have found, however, has often brought up more questions than answers.

The Roman Space Telescope

The Nancy Grace Roman Space Telescope, originally the Wide Field Infrared Survey Telescope, is a cutting-edge observatory that will provide essential insights into the mysteries of dark energy, find planets outside our solar system, and address various other astrophysics and planetary science issues.

The Roman Telescope will be one of the most essential instruments for researching the cosmos. The telescope's Wide Field Instrument will provide a field of view estimated 100 times greater than the Hubble infrared instrument. It will measure light from a billion galaxies over the Missi and, as well as perform a microlensing survey of the inner Milky Way, which is estimated to yield more than 2,600 new exoplanets.

At the same time, its Coronagraph Instrument will perform high-contrast imaging and spectroscopy of individual nearby exoplanets. The mission will be able to produce infrared pictures that are much clearer than those produced by the Hubble Space Telescope. More data is anticipated to be gathered by the spacecraft than by any previous NASA astrophysics mission.

How the Telescope will unravel the Mysteries of the early universe

A new simulation demonstrates how powerful the upcoming Nancy Grace Roman Space Telescope will be when it is completed. According to NASA, the Telescope will "rewind the cosmic clock" and give scientists a new perspective on space. This could aid scientists in their quest to comprehend how the universe changed from a sea of tightly packed particles to the galaxy-rich universe we observe today. The Telescope won't launch until around May 2027 and can potentially revolutionize astronomy since it can photograph enormous swaths of space in a single frame. Roman can picture a portion of the sky in 63 days that would take the Hubble Space Telescope 85 years to image —a great illustration of this increased observational capability.

It is now known that the atoms and light in the universe make up only around five percent of the total mass of the cosmos. The rest is composed of dark matter and dark energy.

The Roman Telescope could aid researchers in investigating the cosmos' biggest mysteries, including studying dark matter and energy. Researchers studying the universe's expansion initially thought that gravity would slow it as time passed. However, Hubble's observations showed that the universe's expansion has sped up over time. Different theories were proposed to explain this, and although we still don't know the correct explanation, the solution has been named dark energy.

Exploring the early universe with NASA's Roman Space Telescope
An Illustration of a planet's energy

What are dark energy and dark matter?

Very little is known about dark energy and dark matter. Because their effects on the universe can be observed, scientists have found that dark energy makes up roughly 68 percent of the universe, and dark matter makes up about 27 percent. The rest, including everything our sensors and all ordinary matter, have ever observed, is "normal" matter.

There are more unknowns than knowns about dark energy and dark matter. It is known that dark energy influences the universe's expansion. Other than that, nothing more certain is known, although several possible explanations exist.

The idea is that dark energy is a property of space. Albert Einstein was the first to realize that empty space is different from nothing. In one theory, Einstein proposed a cosmological constant that allows seemingly empty space to possess its energy. Because the energy is a property of space itself, more of this energy would appear as space expands. This could explain why the universe speeds up as it expands.

However, nobody knows why this cosmological constant should exist in the first place, much less why it would explain the universe's observable acceleration.

According to NASA, a different theory for dark energy is that it is a dynamical energy fluid or field that fills all of space but has an opposite effect on the universe's expansion to that of matter and regular energy. This theoretical field was given the name "quintessence" by some theorists in honor of the fifth element proposed by Greek philosophers as the material that fills the region of the universe beyond the terrestrial sphere. However, if quintessence exists, we still don't know how it works or why it exists.

A third theory is that "empty space" is filled with particles continuously forming and disappearing. However, physicists have been unable to get the math on this to work out.

The Roman Space Telescope will aid astronomers in analyzing the acceleration of the universe's expansion and provide more information about dark energy.

According to Caltech, the Roman Space Telescope's Primary Dark Energy Science Objective is to test possible explanations of the universe's accelerating expansion, including Dark Energy and modifications to Einstein's gravity. The telescope will collect data that will measure the expansion history of the universe and the growth of large-scale structure (the clustering of galaxies and their associated halos of dark matter in the universe) using three complementary techniques:

  • Using the peak brightness of Type Ia supernovae to measure expansion history.
  • Measuring the distribution of dark matter structures through their effect on the light from distant galaxies (weak gravitational lensing).
  • Using primordial sound waves' imprint on galaxies' clustering to measure expansion history.


Planets outside of our solar system are known as exoplanets. Thousands have been found in the last two decades, many using NASA's Kepler Space Telescope. These planets range significantly in size, characteristics, and orbit. The exoplanets can be categorized into: Gas giant, Neptunian, super-Earth, and terrestrial.

Of course, NASA and other organizations are also explicitly hunting for a planet the size of Earth that orbits a sun-like star in the habitable zone and can support life. But even without finding ET, researchers can learn much about our galaxy by studying these planets.

For example, data from NASA’s Kepler spacecraft showed that planets ranging in size between 1.5 and 2 times the diameter of Earth are rare. Some researchers have proposed that this size represents a sort of limit. Planets that reach this size attract thick hydrogen and helium gas atmospheres and balloon up into gas giants. At the same time, planets smaller than this limit are either too minor to hold an atmosphere or, if they orbit close to their stars, they have their atmospheres stripped away.

More information about exoplanets could help explain this and other mysteries and give us a better understanding of how planetary systems form.

To do this, Roman will use a method called microlensing. This takes advantage of gravitational lensing - an observational effect that occurs when a large mass warps the fabric of space-time. This causes light to curve as it travels through the warped space-time.

If the alignment between stars is incredibly close, the nearer star can act like a natural cosmic lens, magnifying light from the background star. Planets orbiting the lens star can produce a similar effect on a smaller scale, which will be detectable by the telescope. If an exoplanet is orbiting a star, the star will become much brighter due to the effects of gravitational lensing. The telescope can then detect this.


The Roman Space Telescope will be a vital instrument for the scientific community. After processing and transmission to the Roman archive, all Roman data will become available to the public. Also, scientists worldwide can utilize the observatory to explore the universe in their ways, from the closest exoplanets to clusters of distant galaxies, by submitting ideas through a competitive competition.

The Roman Space Telescope will serve as a multipurpose mission by developing a variety of cutting-edge technologies, providing a broad view of the cosmos, and assisting in the resolution of some of the astrophysics' most important questions, such as how the universe came to be as it is now and what will be its ultimate fate.

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