LISTSERV - DAILY-ASTRONOMER Archives

2022-2023: XXX

Sunrise: 7:09 a.m.

Sunset: 5:40 p.m.

Civil twilight ends: 6:10 p.m.

Sun's host constellation: Virgo the Maiden

Moon phase: Waxing crescent (2% illuminated)

Moonrise: 8:28 a.m.

Moonset: 6:21 p.m.

Julian date: 2459879.21

"Talking about music is like dancing about architecture."

-Martin Mull

or -Frank Zappa

or -Elvis Costello

or -Thelonius Monk

or -George Carlin

or -Miles Davis

or -Laurie Anderson

or -Abraham Lincoln

or -William Shakespeare

or -Socrates

or -Herodotus

or -Anonymous

THE DAILY ASTRONOMER

Wednesday, October 26, 2022

Space Speed

Let's rewind the clock a bit.

Approximately 13.82 billion years ago, what we regard as OUR Universe took form out of an event dubbed "The Big Bang." (We'll delve far more deeply into this seminal event when we resume our "Egg to Apple" series next week.) This "bang" created space and caused it to first inflate and then expand. When astronomers such as Edwin Hubble (1889-1953), Vesto Slipher (1875-1969) and astronomer/priest Georges Lemaitre (1894-1966) first developed the Big Bang model, they logically presumed that material within the Universe would induce a dampening effect on that expansion. This assumption provided the basis for three different cosmological models: one in which the Universe expands forever; one in which the combined material causes the Universe to slow to a standstill; and lastly a Universe that stop, reverses and ultimately implodes in on itself.

Then, in the 1990, two astronomical research teams discovered, to everyone's astonishment, that this expansion not only not slowing down, but actually accelerating with time. Hence, the discovery of "dark energy," an unknown force deemed responsible for this acceleration. Astronomers still know precious little about this "dark energy," hence the word "dark," signifying our continued ignorance of it. What astronomers can know, and have measured, is the speed at which this expansion occurs. They can estimate this velocity by measuring the expansion between distant supernovae. A recent measurement, however, has given many cosmologists pause because it seems as though the cosmos is expanding far faster than previously assumed.

In a recent paper published in the Astrophysics Journal, a research team studied 1,550 supernovae, some of which were located just beyond the Milky Way and some were observed at the far reaches of the observable Universe. While results of these studies provided further evidence in support of the theory that three-fourths of the Universe consists of Dark Energy and one-fourth of matter -most of which is dark matter-, it did determine that the expansion speed is about 160,000 miles an hour. This speed is far greater than that measured by using the Cosmic Microwave Background radiation. Dillion Brout, co-author of this paper, stated that "potentially something is fishy with our understanding of the Universe."

As we mentioned in yesterday's DA pertaining to the lightest neutron star ever observed, more observations will be required to explain the discrepancy. Why the Universe should be expanding more quickly than previously believed remains a profound mystery. Of course, such mysteries drive scientific progress. We could be close to the advent of a new science, or, at least, a modification to the dark energy model.

We do know that the cosmos is growing faster than anyone would have believed. The ramifications of this higher speed remain unknown....for now.

To subscribe or unsubscribe from the Daily Astronomer:

https://lists.maine.edu/cgi-bin/wa?SUBED1=DAILY-ASTRONOMER&A=