On March 18, 2021, a scientific study, tilled ‘the MUSE Extremely Deep Field: The cosmic web in emission at high redshift’, was published in the journal Astronomy and Astrophysics. As per the study, scientists have captured images of ‘cosmic web’ for the first time using a 3D spectrograph, called the Multi Unit Spectroscopic Explorer (MUSE) instrument, developed for Very Large Telescope (VLT), which is installed on the European Southern Observatory (ESO) at Chile. The image’s simulations established that light was coming from billions of dwarf galaxies. These galaxies are invisible and comprise of trillion of stars.
What is Cosmic Web?
Cosmic web, according to NASA, is the large-scale backbone of the cosmos which consists primarily of the mysterious substance, called, dark matter and gas on which galaxies are built. Cosmic webs are the building blocks of dark matter which cannot be seen but makes up the bulk of the Universe’s material. The web consists of the bright hydrogen gas filaments on which galaxies are created.
About the Discovery
The concept of existence of a web-like structure was introduced as early as 1985, in the Redshift Survey, conducted at the Harvard-Smithsonian Centre for Astrophysics. However, direct images of the web have never been available or observed. Only partial and indirect glimpses of web-like structures were caught by astronomers through quasars (quasi-stellar objects) whose powerful radiation acts like car headlights. Radiation of quasars show gas clouds along the line of sight. These regions, however, do not show the whole network of filaments where galaxies are created.
This was the first time a cosmic web has been observed directly and its images captured. This breakthrough came after eight months of observation of the Hubble Ultra-Deep Field and a year of data processing. The scientists pointed the telescope at a single region of the sky for more than 140 hours.
Implications of the New Findings
Ronald Bacon, a scientist at the Centre for Astrophysics Research in Lyon (CRAL) says, “After an initial period of darkness, the Universe erupted with light and produced a huge number of stars.” However, the question as to what caused the period of darkness to end is important. According to Emanuele Daddi (a researcher at Atomic Energy Commission), this discovery is fundamental and will help in understanding how galaxies were formed. It will have larger implications in understanding the origin of the Universe.
The Multi Unit Spectroscopic Explorer (MUSE) is an innovative 3D spectrograph for ESO’s Very Large Telescope (VLT). It has a wide field of view which provides simultaneous spectra of several adjacent regions in the sky. It is an efficient instrument for exploring of the Universe in three dimensions.
The European Southern Observatory (ESO) is an intergovernmental science and technology organisation in astronomy. It plays an important role in enabling important scientific discoveries and also promotes cooperation in astronomical research. The VLT is an array of four Unit Telescope, each with a main mirror measuring 8.2 metres in diameter and four movable 1.8 m diameter Auxiliary Telescopes.
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