Webb Telescope Confirms: Universe is Expanding

WASHINGTON, Dec 9 (Reuters) - Fresh corroboration of the perplexing observation that the universe is expanding more rapidly than expected has scientists pondering the cause - perhaps some unknown factor involving the mysterious cosmic components dark energy and dark matter.

Two years of data from NASA's James Webb Space Telescope have now validated the Hubble Space Telescope's earlier finding that the rate of the universe's expansion is faster - by about 8% - than would be expected based on what astrophysicists know of the initial conditions in the cosmos and its evolution over billions of years. The discrepancy is called the Hubble Tension.  READ MORE...

Webb Telescope Shatters Records

The very first results from the James Webb Space Telescope seem to indicate that massive, luminous galaxies had already formed within the first 250 million years after the Big Bang. If confirmed, this would seriously challenge current cosmological thinking. For now, however, that’s still a big “if.”

Shortly after NASA published Webb’s first batch of scientific data, the astronomical preprint server arXiv was flooded with papers claiming the detection of galaxies that are so remote that their light took some 13.5 billion years to reach us. Many of these appear to be more massive than the standard cosmological model that describes the universe’s composition and evolution.

“It worries me slightly that we find these monsters in the first few images,” says cosmologist Richard Ellis (University College London).

Young, massive stars in newborn galaxies emit vast amounts of energetic ultraviolet radiation. As this light moves through expanding space for billions of years, the wavelengths stretch (redshift) all the way into the infrared – radiation that Webb’s instruments are sensitive to.

It takes careful spectroscopic measurements – either by Webb’s spectrometers or by the ground-based ALMA observatory that operates at even longer wavelengths – to precisely determine the redshifts, which tells you how far out into space — and thus how far back in time — you’re looking. But there’s a quick (albeit less reliable) workaround that gives a rough idea.

Neutral hydrogen atoms in intergalactic space absorb ultraviolet radiation at wavelengths shorter than 91.2 nanometers. For remote objects, this threshold also redshifts to longer wavelengths, into the infrared for the most distant galaxies. 

Since Webb’s near-infrared camera NIRCam takes measurements through a large number of filters, each covering a different wavelength band, a galaxy may be visible in some channels but not in others. The wavelength band in which the galaxy disappears roughly indicates its redshift, and the corresponding look-back time.  READ MORE...

More From the Webb Telescope

We previewed our uncrewed Artemis I mission to the Moon during a pair of briefings. On August 3, agency officials at our NASA Headquarters and at other NASA centers provided a “big picture overview” of the mission.

“Artemis I shows that we can do big things. Things that unite people, things that benefit humanity. Things like Apollo that inspire the world.” — Bill Nelson, NASA Administrator

That was followed two days later with a deeper dive into the mission’s timeline and operations from our Johnson Space Center. 

The agency is currently targeting no earlier than Monday, August 29, for the launch of the Space Launch System rocket to send the Orion spacecraft around the Moon and back to Earth. 

Artemis I will take place over the course of about six weeks to check out systems before astronauts fly aboard the spacecraft on Artemis II.

This image of the Cartwheel and its companion galaxies is a composite from Webb’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI), which reveals details that are difficult to see in the individual images alone.

This galaxy formed as the result of a high-speed collision that occurred about 400 million years ago. The Cartwheel is composed of two rings, a bright inner ring, and a colorful outer ring. 

Both rings expand outward from the center of the collision like shockwaves. Credit: NASA, ESA, CSA, STScI, Webb ERO Production Team.  READ MORE...