The expanding universe – cosmic dynamics

Musings, ,   1 comment  

The universe is expanding. For billions of years. How fast is the expansion? Measuring this rate is a big deal in physics. Why?

Gravitationally lensed supernova
Galaxy cluster PLCK G165.7+67.0 is shown, with the features of background, gravitationally lensed galaxies appearing behind it. The big orange arc at left, called “Arc 2,” contains the second-most distant type Ia supernova, and it was seen by JWST on repeat in all three images, as annotated here. Credit: B. Frye et al., ApJ submitted, 2023; Annotations: E. Siegel

• Big Think > “JWST’s first triple-image supernova could save the Universe” by Ethan Siegel (Sept 20, 2023) – A gravitationally lensed star named “Supernova H0pe” might refine measurement of the cosmic expansion rate.

The most direct method of measuring the expansion rate, by looking at more and more distant objects and tracking how quickly they appear to recede from us, consistently gives answers that are about 9% higher than the values we get from looking at signals imprinted in the very early Universe [cosmic microwave background].

In a new paper just submitted on September 13, 2023, Dr. Brenda Frye and collaborators spotted a type Ia supernova that appeared in triple: magnified and distorted by the gravity of a foreground galaxy cluster. It just might be the key to measuring, to greater precision and accuracy than ever before, exactly how the Universe truly is expanding.

1 comment on “The expanding universe – cosmic dynamics”

  1. Protostar outflows
    Image credit: ESA/Webb, NASA, CSA, Tom Ray (Dublin)

    How do stars form and evolve? Particularly stars like our Sun. Astronomers using the JWST are finding “cosmic eye candy” of (gas-and-dust shrouded) protostar dynamics.

    • Space.com > “Stunning James Webb Space Telescope image shows young star blasting supersonic jets” by Sharmila Kuthunur (September 14, 2023) – HH 211 is one of the youngest and nearest examples of a newer star spewing out matter.

    The jets, which are together called Herbig-Haro 211 (HH 211), live in an energetic pocket of space located about 1,000 light-years away from Earth in the constellation Perseus. In this region, a protostar is actively sucking in surrounding gas and dust to grow larger, but is meanwhile shedding material into space … And as those jets of material zoom through space… their interactions with interstellar matter [appear] as bright, colorful [gas] swirls.

    By studying data about HH 211 … researchers realized the jets from young stars are much slower and richer in molecules such as carbon monoxide, silicon monoxide and molecular hydrogen. This is in comparison to the faster jets that blast out of older stars. According to a recent study outlining the JWST’s observations …, that’s primarily because the shock waves surrounding the young star are not yet strong enough to shred the jets’ molecules into individual atoms.

Comments are closed.