Hubble finds new figure for universe expansion rate

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The uncertainty of science: Using data from the Hubble Space Telescope astronomers have found evidence that universe’s expansion rate is faster than estimated in previous measurements.

The new findings show that eight Cepheid variables in our Milky Way galaxy are up to 10 times farther away than any previously analyzed star of this kind. Those Cepheids are more challenging to measure than others because they reside between 6,000 and 12,000 light-years from Earth. To handle that distance, the researchers developed a new scanning technique that allowed the Hubble Space Telescope to periodically measure a star’s position at a rate of 1,000 times per minute, thus increasing the accuracy of the stars’ true brightness and distance, according to the statement.

The researchers compared their findings to earlier data from the European Space Agency’s (ESA) Planck satellite. During its four-year mission, the Planck satellite mapped leftover radiation from the Big Bang, also known as the cosmic microwave background. The Planck data revealed a Hubble constant between 67 and 69 kilometers per second per megaparsec. (A megaparsec is roughly 3 million light-years.)

However, the Planck data gives a constant about 9 percent lower than that of the new Hubble measurements, which estimate that the universe is expanding at 73 kilometers per second per megaparsec, therefore suggesting that galaxies are moving faster than expected, according to the statement.

“Both results have been tested multiple ways, so barring a series of unrelated mistakes, it is increasingly likely that this is not a bug but a feature of the universe,” Riess said. [emphasis mine]

I should point out that one of the first big results from Hubble in 1995 (which also happened to be the subject one of my early published stories), the estimate then for the Hubble constant was 80 kilometers per second per megaparsec. At the time, the astronomers who did the research were very certain they had it right. Others have theorized that the number could be as low as 30 kilometers per second per megaparsec.

What is important about this number is that it determines how long ago the Big Bang is thought to have occurred. Lower numbers mean it took place farther in the past. Higher numbers mean the universe is very young.

That scientists keep getting different results only suggests to me that they simply do not yet have enough data to lock the number down firmly.



  • Localfluff

    Edwin Hubble’s own first estimate, in the early 1920s, was 500 km/pc/s. 73 or 500, same same in astronomical terms. They make statistical inferences from a sample of one (as long as it isn’t anthropicly introspective, although maybe everything can be nothing but?). But any increase of the estimate is a bit bad news for the JWST, I think, for its ambition to catch the light of the very first stars ever born. If it doesn’t see the first galaxies and super massive black holes, but only mature ones that must’ve spent a looong time to merge, it would be a conundrum larger than the universe. It wouldn’t be the first time that happens.

    I fully support the concentration of all available resources on forging unique items like the JWST, LIGO and Tolkien’s Ring of Power. A thousand minor missions wouldn’t be anything of a substitute for reaching deeper into the unknown. If one doesn’t detect gravitational waves, if one doesn’t detect neutrino, if one doesn’t see back to the time when God said: “Let there be light!”, then one misses some pretty fundamental pieces of the puzzle.

    The astronomer’s prayer, inherited from the astrologer’s prayer repeated ever since the birth of the first human being:

    Mirror mirror in the sky
    Tell me where we are and why
    Space black lord don’t be so shy
    All our eager eyes you spy

  • BSJ

    One story on this claims Dark Radiation may be responsible for the discrepancies.

    Why is it that every time the math doesn’t match the observation they have to invent something ‘dark’ to explain it?

    What would Galileo say?

  • Localfluff

    Galileo Galilei would say alot. He was a controversial talk-aloter. Not a conformist gender/climate science outreach person by today’s standards.

    And the solution to the conundrum is Dark Math.
    I discovered it while sleeping on the math lessons, it is all philosophically very clear to me now…

  • BSJ

    I gotta admit. That’s pretty funny!

    I meant Galileo the ‘observationalist’.

    The Pope said it’s “Celestial spheres that rule the Heavens”.

    Galileo said, “Nuh-uh look through my telescope”.

    The Pope said “No way! That’s dark magic” ]:-}

    Galileo said “I triple dog dare you!”

    Pope says “I burn you at the stake…”

    Galileo “OK, You win, for now ” :-(

  • e

    Why is it that every time the math doesn’t match the observation they have to invent something ‘dark’ to explain it?


  • Localfluff

    As I understand the history, Galileo was a good personal friend with the pope, at least until he started using a telescope (those wretched lenses that distort the light of God’s creation). But he was the kind of guy who sought controversy and fame. He got a house arrest. An almost symbolic action for the Church to retain some kind of authority. The Church never administered any punishments. It just gave theological advice to the Fürst (Prince), the worldly power, for him to give verdict about worldly things like human bodies.

    Just a few decades later, Newton in England thought it all through very well, and he got a royal funeral. Although (or maybe because?) he was a very disagreeable person as opposed to the talkative Galileo. That’s why Italy, after thousands of years of cultural leadership, was replaced by England and its mechanically powered world empire.

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