The Universe expanding faster than it did in the past, hints Hubble
For over a century now, scientists have known that the universe is constantly expanding. During studies into the early state of the Universe, in the era after the theorized Big Bang, the cosmos was shown to be expanding at a certain speed.
However, recent studies into the current state of the Universe has shown that is now expanding at a much faster rate than before. Astronomer, Edwin Hubble first observed that every distant galaxy they could measure appeared to be drifting away from Earth—and the farther they were, the faster they receeded.
In recent times, using the Hubble Space Telescope, astronomers have continually measured the expansion rate of today’s universe but mysteriously, the number measured by the Eurpoean Space Agency’s Planck Spacecraft recorded a 9 percent increase in the current expansion of our universe in comparison with the early universe.
Though, astronomers at the time remarked that the disagreements in the results were a fluke—placing the odds at 1 in 3,000. However, in a recent study, scientists have refined the Hubble measurements, noting that today’s universe is expanding faster than it was in the past, reducing the odds of a mistake to 1 in 100,000. This points to an anomaly and now, astronomers are battling to discover its cause.
Astronomy has been studied for many centuries now and with these recent developments, more and more scientists would delve into the subject. However, for those who have keen interest in astronomy, knowing critical terms is important. It helps to educate one on the vast wonders of this complex universe as it is the first step in acquiring the kind of advanced knowledge of our universe that is needed to understand our place in it.
Author G. Cyr published Astroglossary: Revised Edition a highly comprehensive and easily understandable astronomy reference book that acts as an invaluable source of information for all terms needed to understand modern astronomy, while also giving readers a deeper appreciation of our universe.
With astronomers now faced with this befuddling discovery, the journey to unravelling this mystery would require indepth understanding of the workings of the Universe.
The Hubble Constant is a measure of how fast a galaxy is moving in comparison to how far away it is. This method for measuring cosmic expansion has been become a tradition, set down by pioneers in this field. By just looking at Cepheid variables—which are stars that change their brightness on rhythmic, presictable timescales—astronmers are able to measure distances.
Harvard astronomer, Henrietta Swan Leavitt is credited with being the first person to discover that the intrinsic brightness of one of these stars has a direct connection to the time it takes to cycle from dim to bright.
Since distant stars appear dimmer, astronomers can now use the timing of the star’s cycle and its brightness to measure its distance. This information was used by Edwin Hubble to make one of his very first measurement of his constant. Now, astronomers like Nobel Laurete Adam Riess are using the Hubble Telescipe to achieve the same thing, but with a much greater accuracy.
In a newly released paper, which has been approved for publication in the Astrophysical Journal, Riess led a team called SH0ES (Supernovae H0 for the Equation of State), to pin down the Hubble constant to unprecedented precision.
The result of their observations showed that the earlier measurements of the Hubble Constant in the nearby universe were accurate—coming as a surprise to Riess and his team because it confirmed earlier disagreements with the Planck telescope.
The spacecraft measures fundamentals about the early universe, mapping the cosmic microwave background and calculating the ratio of dark matter, dark energy, and normal matter.
Riess’ measurements however, is not unique as it matches a host of other measurements from today’s universe. In similar fashion, for the first few hundred thousand years after the Big Bang, Planck’s numbers are backed up by other measurements of the early universe.Thus, it is highly unlikely that either of them would change at this point.
“This is not just two experiments disagreeing,” Riess explained in a press release. “We are measuring something fundamentally different. One is a measurement of how fast the universe is expanding today, as we see it.”
“The other is a prediction based on the physics of the early universe and on measurements of how fast it ought to be expanding. If these values don’t agree, there becomes a very strong likelihood that we’re missing something in the cosmological model that connects the two eras.”
The disparities in these two numbers are constantly pointing to the fact that our early universe behaved a lot differently than it is today, in terms of expansion.
However, while dark energy is still deeply misunderstood, it is best described as the energy that causes expansion, starting from the Big Bang’s first outward rush to the unusual movement astronomersare witnessing today.
Since dark energy is an integral part of the standard cosmological model, itis possible that it worked in an unusual manner, leadingto a rise in the universe’s expansion at some point after the Big Bang. Riess suggests “dark radiation” like neutrinos hold the key as they are particles that travel at nearly the speed of light but rarely interact with normal matter.
Whatever the case may be, Riess notes that astronomers would need to accept that these two numbers are genuinely different. Rather,they should shifttheir focus on finding a resolution by creatingmore accurate models of our universe.