Indian scientists recently detected what could be one of the universe’s farthest objects. The world’s highest Gamma-Ray Telescope, MACE, situated at Hanle in Ladakh has detected a ‘blast from the past’, well before the Earth and/or the Solar System were even born.

Scientists from the Bhabha Atomic Research Center, Mumbai part of the Department of Atomic Energy, have detected an explosion from a galaxy, of what is also called a Gamma Ray flare. They say it comes from a source eight billion light years away. The discovery, made on Republic Day this year, provides a new understanding of how the Universe is made.

A ‘light year’ is a measure of distance and not time. One light year means the distance covered by a ray of light or photon to travel in a year. Incidentally, a photon or a ray of light takes nearly eight minutes to travel from the sun to Earth, which is nearly 150 million kilometers away.

Scientists estimate that the Earth was formed some 4.5 billion years ago. Extrapolating from this finding, scientists suggest that this intense flare is at least 3.5 billion years older than even the time of the birth of the Earth.

Scientists from BARC report that ‘in a ground breaking observation, the Major Atmospheric Cherenkov Experiment (MACE) telescope located at Hanle has detected an intense gamma-ray flare from the distant quasar OP 313, also known as B2 1308+326’.

The scientists report that ‘it is approximately 8 billion light-years away from Earth. This means the light we observe today from OP 313 began its journey when the universe was less than half its current age!’ The finding has since then been observed by other Gamma Ray telescopes like those in Russia and the USA.

In the cold desert of Ladakh at Hanle is a telescope like no other, a special robotic eye in the sky to track some of the most energetic phenomenon like the birth and death of stars. Special instruments are required to study these exploding stars.

The Department of Atomic Energy established the Major Atmospheric Cherenkov Experiment or MACE a cutting-edge gamma-ray telescope for very high-energy astronomy. It is indigenously developed by the Bhabha Atomic Research Centre in Mumbai.

About 4,300 above sea level, in Ladakh’s Hanle, the massive telescope is always waiting for signals as India tries to decode some of the universe’s greatest mysteries such as black holes, supernovae and dark matter.

The MACE (Major Atmospheric Cherenkov Experiment Telescope) has a diameter of 21 meters, weighs 180 tonnes and has 356 mirror panels. It is the largest telescope in Asia and the highest in the world. It is armed with a high-resolution imaging camera that weighs about 1200 kg. It is being used to study black holes and dark matter.

Hanle, Ladakh:

It is a telescope like no other, a special robotic eye in the sky to track some of the most energetic phenomena such as the birth and death of stars. One needs very special instruments to study these exploding stars. India now holds the honour of having the world’s highest-altitude gamma ray telescope situated at 4,270 metres above sea level and it has the largest mirror in Asia.

The Department of Atomic Energy (DAE) established the Major Atmospheric Cherenkov Experiment or MACE. It is a cutting-edge gamma ray telescope for very high energy astronomy. It was developed by the Bhabha Atomic Research Centre (BARC), Mumbai and is installed at Hanle, Ladakh.

“Hanle is like heaven for gamma ray astronomers with its dark skies, low humidity and almost no air pollution,” said Dr AK Mohanty, chairman, Atomic Energy Commission and India’s nuclear chief.

He said another few more gamma ray telescopes could be built here, making Hanle the go-to place for global astronomers, some with international collaboration.

According to DAE, the MACE telescope, due to its high sensitivity, will be able to detect gamma rays from supernova remnants, pulsars and micro-quasars. It will also peep into the centres of distant galaxies hosting supermassive blackholes and will be able to discover the high-energy processes occurring around it. The MACE telescope will be used to search for dark matter in the universe and unravel its mysteries.

The event where locals participated in large numbers has been titled ‘Juley Cosmos’. “Juley” is a salutation used by Ladakhis, which the DAE says is made-in-India but made for the world. It is situated not far from the China border, some 250 km from Ladakh’s capital Leh.

The conceptualisation and design were carried out by the Astrophysical Sciences Division of BARC. The MACE telescope has been commissioned at Hanle, at an altitude of 4,270 metres above mean sea level. It is required to accurately position the large mechanical structure, having a 21-metre diameter reflector in less than three minutes. This requires careful selection of lightweight construction, approximately 175 tonnes, and simultaneously maintaining high strength and temperature endurance. Transport constraints in the Ladakh region restrict the size of sub-components to less than 2.5 metres.

Reflector surface measuring over 350 square metres (sqm) comprises highly reflective diamond-turned custom-built metallic mirror facets that are required to be aligned with an accuracy of 2 mm over parabolic surface. The camera at the focal point contains a number of photomultiplier tubes mounted with specialised assembly to enhance light collection efficiency.

Ultrafast backend electronics with nanosecond digitization electronics is optimised for low-power and -temperature operations. Extreme weather conditions restrict transport to six-eight months a year and affect the availability of trained personnel on site.

MACE is currently the largest Cherenkov telescope in Asia. It is the highest altitude observatory among similar facilities in the world. The site has been carefully chosen for its unique scientific advantages as Hanle offers extremely low light pollution required for gamma ray observations. The longitudinal advantage of its location enables MACE to observe sources invisible to other parts of the world.

MACE is 21 metres in diameter, 175 tonnes heavy, has reflector area of 356 sqm and 1,424 diamond-turned metallic mirror facets, 712 actuators, 1,088 photo-multiplier tubes, and 68 camera modules.

At the inauguration, Dr Annapurni Subramaniam, director of the Indian Institute of Astrophysics that is the host agency for the Indian Astronomy Observatory at Hanle, said, “The MACE telescope is an engineering marvel as it withstands the very high winds of Hanle.”

Even before its formal inauguration, the telescope produced high-quality work detecting gamma ray flares as far away as 200 million light years away and detected during observation on a freezing December night in 2022.  This high-altitude telescope is the world’s envy and India’s pride.