How Far Back In Time Can We Possibly Look With James Webb Telescope?

The Hubble Space Telescope has discovered Earendel, which means morning star, which is the most distant star ever discovered. We wouldn’t typically be able to observe Earendel, which is 50 times the mass and millions of times brighter than the Sun.

We can see it because the star is aligned with a huge galaxy cluster in front of it, whose gravity bends the star’s light, making it brighter and more focused – effectively producing a lens.

Why Do We See Distant Past When We Look At Distant Objects In Space?

When we look at distant objects, astronomers see into the distant past. Because light travels at a constant speed, the distance between us and an object determines how long it takes for the light to reach us.

When we examine the light of a star, we are gazing at light that was released 12.9 billion years ago – this is referred to as the lookback time. Only 900 million years have passed since the Big Bang. However, due to the tremendous expansion of the universe during the time it took this light to reach us, Earendel is now 28 billion light years away.

Is James Webb Capable Of Observing The Distant Past?

Now that Hubble’s successor, the James Webb Space Telescope (JWST), is operational, it may be possible to discover even earlier stars; however, there may not be many that are well aligned enough to produce a “gravitational lens” that humans can observe.

The objects must be extremely brilliant in order to see further back in time. The most massive and brilliant galaxies are the farthest things we’ve observed. The brightest galaxies are those that include quasars, which are luminous objects driven by supermassive black holes.

Prior to 1998, the farthest identified quasar galaxies had a lookback time of around 12.6 billion years. The Hubble Space Telescope’s improved resolution raised the lookback period to 13.4 billion years, and we expect the JWST to improve this to 13.55 billion years for galaxies and stars.

Why Do We Need To Observe Stars At The Cosmic Dawn?

The cosmic dawn began a few hundred million years after the Big Bang, when stars began to form.

We’d like to be able to observe the stars at the cosmic dawn since it would corroborate our theories about the formation of the cosmos and galaxies. However, a new study implies that we may never be able to observe the farthest objects in as much detail with telescopes as we would like – the universe may have a basic resolution limit.

Why Is It Important To Look Back In Time?

JWST’s major purpose is to figure out what the early universe was like and when the first stars and galaxies were formed, which is estimated to be between 100 million and 250 million years after the Big Bang. And, fortunately, we can learn more about this by looking back further than Hubble or the JWST can.

Why Can’t We See Beyond The Cosmic Microwave Background?

Although we can see light from 13.8 billion years ago, it is not starlight because there were no stars at that time. The cosmic microwave background (CMB), which is radiation left over from the Big Bang and formed only 380,000 years after our cosmic beginning, is the furthest light we can see.

Before the CMB, the universe included charged particles like positive protons (which, combined with neutrons, make up the atomic nucleus) and negative electrons, as well as light. The charged particles scattered the light, turning the universe into a hazy soup. The universe cooled as it expanded, and the electrons finally joined with the protons to form atoms.

This is because the atoms had no charge, unlike the soup of particles, light was no longer scattered and could travel in a straight line through the universe. This light has traveled throughout the universe till it reaches us now.

As the universe expanded, the wavelength of light lengthened, resulting in microwaves, which humans now observe. The CMB is a consistently visible light that may be observed throughout the sky. The CMB can be found everywhere around the galaxy.

Why Can’t We See Light From the Previous Era?

We can’t see light from previous eras since it was scattered and the universe was opaque, therefore the CMB light is the furthest back in time that we have seen.

However, it’s possible that we’ll be able to see beyond the CMB in the future. We won’t be able to do it with light; instead, gravitational waves will be required. These are strewn over the fabric of spacetime. If any developed in the obscurity of the very early universe, they might have made it to us today.

The LIGO detector discovered gravitational waves from the merger of two black holes in 2015. Perhaps the next generation of space-based gravitational wave detectors, such as Esa’s Lisa satellite telescope, which is scheduled to launch in 2037, will be able to peer into the very early cosmos before the CMB formed 13.8 billion years ago.

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