A fresh analysis of data from Hubble Space Telescope and other observatories carried out by a team of astronomers from the UK has revealed that there are 2,000 billion galaxies in the Universe. The new count of galaxies is almost ten times more than the previous count.
In astronomy, a fundamental question most frequently asked is just how many galaxies are present in the universe, and astronomers estimate that the observable universe contains about 200 billion galaxies.
The detailed findings of the new study have been presented in a paper titled “The Evolution of Galaxy Number Density at Z < 8 and its implications”. In this study, the team led by Christopher Conselice of the University of Nottingham examined the images captured by the Hubble Space Telescope and other observatories. Researchers converted old Hubble pictures into 3D to make exact measurements of the “number of galaxies at different epochs in the universe’s history.” They used mathematical models to infer the existence of galaxies that can’t be observed by the current telescopes. The analysis led to conclusion that there must be an additional 90 percent of galaxies in the observable universe that are too faint and too far away to be observed with present-day telescopes.
Scientists are however working on creating more sensitive telescopes that would be able to spot these galaxies in future. The James Webb Space Telescope is one such telescope under construction, whose primary mirrors with a diameter of 6.5 m will dwarf Hubble’s mirrors with diameter of 2.4 m. James Webb Telescope will be installed at the L2 point, past the orbit of the moon. Comparatively, it will be a much better spot than Hubble’s orbit which is just 570 km from Earth. The Webb ‘scope will also be a better observer of infrared light, thanks to the shields installed on it to block the light.
“It boggles the mind that over 90 per cent of the galaxies in the universe have yet to be studied. Who knows what interesting properties we will find when we discover these galaxies with future generations of telescopes? In the near future, the James Webb Space Telescope will be able to study these ultra-faint galaxies,” Conselice said.
“These results are powerful evidence that a significant galaxy evolution has taken place throughout the universe’s history, which dramatically reduced the number of galaxies through mergers between them – thus reducing their total number,” Conselice explained.
Conselice believes the Webb Telescope will be able to observe the galaxies that his team infers in this study. The new telescope is scheduled to be launched in October 2018.
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