In order to explore the dark energy, the Dark Energy Spectroscopic Instrument (DESI) at Berkeley Lab has created largest and most detailed ever 3D map of the ब्रम्हांड by obtaining optical spectra from millions of galaxies and quasars. The idea is to measure the effect of dark energy on the expansion of the ब्रम्हांड by accurately measuring the expansion history over the past 11 billion years, through measurement of the position and receding velocity of about 40 million galaxies.
Until late nineties, it was thought that expansion of the ब्रम्हांड following Big Bang about 13.8 billion years ago, should slow down due to gravitational attraction between galaxies, stars and other matter in the cosmos. However, on 8 January 1998, astronomers of सुपरनोवा Cosmology Project announced the discovery that Universe’s expansion is actually speeding up (instead of slowing down). This finding was soon confirmed independently by the High-Z Supernova Search Team.
For about a century, the ब्रम्हांड was thought to be expanding as a result of Big Bang. The discovery that the expansion of the ब्रम्हांड is actually accelerating means something else must overcome gravitational attraction and drive the acceleration of Universe’s विस्तार।
‘Dark’ energy is thought to drive the acceleration of Universe’s expansion. ‘Dark’ means lack of knowledge. Very little is known about the dark energy, however, it is known that the mysterious dark energy constitutes about 68.3% of the mass energy content of the ब्रम्हांड (the rest 26.8% is made up of dark matter, which clusters gravitationally but does not interact with light and the remaining 4.9% constitutes the entire observable ब्रम्हांड including all the ordinary regular matter that we all are made up of).
This is one aspect about the ब्रम्हांड that remains largely unknown to science today.
बर्कले लैब में डार्क एनर्जी स्पेक्ट्रोस्कोपिक इंस्ट्रूमेंट (DESI) को डार्क एनर्जी का पता लगाने के लिए डिज़ाइन और कमीशन किया गया है। DESI का मुख्य लक्ष्य डार्क एनर्जी की प्रकृति का अध्ययन करना है। समय के साथ इसका ऊर्जा घनत्व कैसे विकसित होता है और यह पदार्थ के समूहन को कैसे प्रभावित करता है? ऐसा करने के लिए, DESI दो ब्रह्माण्ड संबंधी प्रभावों को मापने के लिए अपने मानचित्रों का उपयोग करता है: बेरियन ध्वनिक दोलन और रेडशिफ्ट-स्पेस विकृतियां।
In the last seven months of operation, DESI has prepared the largest and most detailed 3D map of the ब्रम्हांड to date. The map shows locations of about 7.5 million galaxies up to a distance of 10 billion light-years. In the next five years, DESI will log 35 million galaxies covering almost one third of the observable ब्रम्हांड.
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स्रोत:
लॉरेंस बर्कले राष्ट्रीय प्रयोगशाला। समाचार विज्ञप्ति - डार्क एनर्जी स्पेक्ट्रोस्कोपिक इंस्ट्रूमेंट (DESI) ब्रह्मांड का सबसे बड़ा 3D मानचित्र बनाता है। 13 जनवरी 2022 को पोस्ट किया गया। पर उपलब्ध है https://newscenter.lbl.gov/2022/01/13/dark-energy-spectroscopic-instrument-desi-creates-largest-3d-map-of-the-cosmos/
