Outpacing All Expectations of Its Expansion Rate
Johns Hopkins University Applied Physics Laboratory | 2019 Apr 25
New measurements from NASA’s Hubble Space Telescope confirm that the Universe is expanding about 9% faster than expected based on its trajectory seen shortly after the big bang, astronomers say.
- This is a ground-based telescope’s view of the Large Magellanic Cloud, a satellite galaxy of our Milky Way. The inset image, taken by the Hubble Space Telescope, reveals one of many star clusters scattered throughout the dwarf galaxy. (Credit: NASA, ESA, Adam Riess, and Palomar Digitized Sky Survey)
The new measurements, published April 25 in Astrophysical Journal, reduce the chances that the disparity is an accident from 1 in 3,000 to only 1 in 100,000 and suggest that new physics may be needed to better understand the cosmos. ...
In this study, Riess and his SH0ES (Supernovae, H0, for the Equation of State) Team analyzed light from 70 stars in our neighboring galaxy, the Large Magellanic Cloud, with a new method that allowed for capturing quick images of these stars. The stars, called Cepheid variables, brighten and dim at predictable rates that are used to measure nearby intergalactic distances.
The usual method for measuring the stars is incredibly time-consuming; the Hubble can only observe one star for every 90-minute orbit around Earth. Using their new method called DASH (Drift And Shift), the researchers using Hubble as a “point-and-shoot” camera to look at groups of Cepheids, thereby allowing the team to observe a dozen Cepheids in the same amount of time it would normally take to observe just one.
With this new data, Riess and the team were able to strengthen the foundation of the cosmic distance ladder, which is used to determine distances within the Universe, and calculate the Hubble constant, a value of how fast the cosmos expands over time. ...
Latest Hubble Measurements Suggest Disparity
in Hubble Constant Calculations is not a Fluke
ESA Hubble Science Release | 2019 Apr 25
Mystery of the Universe's Expansion Rate Widens with New Hubble Data
NASA | GSFC | STScI | HubbleSite | 2019 Apr 25
Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination
of the Hubble Constant and Stronger Evidence for Physics Beyond ΛCDM ~ Adam G. Riess et al
- arXiv.org > astro-ph > arXiv:1903.07603 > 18 Mar 2019, 27 Mar 2019 (v2)
Measurement of the Hubble Constant ~ W. D'Arcy Kenworthy, Dan Scolnic, Adam Riess
- Astrophysical Journal 875(2):145 (2019 Apr 20) DOI: 10.3847/1538-4357/ab0ebf
- arXiv.org > astro-ph > arXiv:1901.08681 > 24 Jan 2019, 11 Mar 2019 (v2)