Radio telescopes: probing space

Subject : Science and technology

Section: Space technology

Concept :

A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light).
The word telescope now refers to a wide range of instruments detecting different regions of the electromagnetic spectrum and in some cases other types of detectors.

Radio Telescope

A radio telescope is a specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky.
Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency portion of the electromagnetic spectrum emitted by astronomical objects, just as optical telescopes are the main observing instrument used in traditional optical astronomy which studies the light wave portion of the spectrum coming from astronomical objects.
Unlike optical telescopes, radio telescopes can be used in the daytime as well as at night.
Since astronomical radio sources such as planets, stars, nebulas and galaxies are very far away, the radio waves coming from them are extremely weak, so radio telescopes require very large antennas to collect enough radio energy to study them, and extremely sensitive receiving equipment.
As the atmosphere is transparent for radio waves, radio telescopes in space are of most use for Very Long Baseline Interferometry; doing simultaneous observations of a source with both a satellite and a ground-based telescope and by correlating their signals to simulate a radio telescope the size of the separation between the two telescopes.
Observations can be of supernova remnants, masers, gravitational lenses, starburst galaxies, and many other things.

Square Kilometre Array- world’s largest radio telescope

The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, with eventually over a square kilometres (one million square metres) of collecting area.
The scale of the SKA represents a huge leap forward in both engineering and research & development towards building and delivering a unique instrument, with the detailed design and preparation now well underway.

SKAO

It is a new intergovernmental organisation dedicated to radio astronomy and is headquartered in the UK.
At the moment, organisations from ten countries are a part of the SKAO.
These include Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, the Netherlands and the UK.

Significance of SKA telescope

The telescope, proposed to be the largest radio telescope in the world, will be located in Africa and Australia whose operation, maintenance and construction will be overseen by SKAO.
Some of the questions that scientists hope to address using this telescope include the beginning of the universe, how and when the first stars were born and the life-cycle of a galaxy.
It would explore the possibility of detecting technologically-active civilizations elsewhere in our galaxy and understanding where gravitational waves come from.
As per NASA, the telescope will accomplish its scientific goals by measuring neutral hydrogen over cosmic time, accurately timing the signals from pulsars in the Milky Way.

SARAS-3 Radio Telescope

SARAS is a niche high-risk high-gain experimental effort of Raman Research Institute.
SARAS aims to design, build and deploy in India a precision radio telescope to detect extremely faint radio wave signals from the depths of time, from our “Cosmic Dawn” when the first stars and galaxies formed in the early Universe.