January 27, 2023

Scientists have revealed why a mysterious radio signal is transmitted from 9 billion light-years away

Scientists have detected a mysterious radio wave that started nine billion light years from Earth.

But before you get excited, this isn’t a sign that aliens are trying to contact us from another corner of the universe.

Instead, cosmologists from the Indian Institute of Science and McGill University say the signal was emitted by a star-forming galaxy 8.8 billion years ago.

Characteristics of the signal indicate that it came from hydrogen gas in a distant galaxy named “SDSSJ0826+5630”.

Scientists have detected a mysterious radio wave that started life nine billion light-years from Earth. Pictured: an image of a radio signal from the galaxy SDSSJ0826+5630

The radio wave in question was captured by the Giant Metrewave Radio Telescope in Pune (pictured), India, and had a wavelength of 48 cm

The radio wave in question was captured by the Giant Metrewave Radio Telescope in Pune (pictured), India, and had a wavelength of 48 cm

What is a “red transmission”?

As radiation travels through expanding space, its wavelength is stretched and frequency is reduced, through what is known as a “redshift”.

The magnitude of the redshift allows scientists to calculate when the waves are emitted.

“It’s the equivalent of looking back at a time of 8.8 billion years,” said Dr Arnab Chakraborty of McGill University.

Hydrogen is of great interest to physicists because it is the simplest element and one of the basic building blocks of the universe.

After the Big Bang, about 13.8 billion years ago, hydrogen spread throughout the universe in the form of fog from which the first stars and galaxies were formed.

Scientists are always looking for waves that can be traced back to this early hydrogen, to discover more about the formation of the universe.

The radio wave in question was captured by the Giant Metrewave Radio Telescope in Pune, India, and had a wavelength of 48 cm.

However, researchers from Montreal, Canada and Bangalore, India have concluded that this particular radio signal has already come to life with a wavelength of 21 cm.

Neutral hydrogen atoms emit waves with a characteristic wavelength of 21 cm and a frequency of 1420 MHz.

This enables them to pierce clouds of dust and cover great distances across the universe, some of which are eventually discovered by Earth-bound scientists.

But as this radiation travels through expanding space, its wavelength is stretched and its frequency decreases, through what is known as a “redshift”.

The redshift allows scientists to calculate how long it has been since the wave was emitted which, in this case, was when our galaxy was only 4.9 billion years old.

Gravitational lensing is where the gravity of a massive object amplifies electromagnetic radiation.  Massive objects like galaxies cause space-time to bend around them, and if they are in the path of light rays, the rays will have to take different paths to bend around them as well.  The rays then converge on the other side as one focused ray

Gravitational lensing is where the gravity of a massive object amplifies electromagnetic radiation. Massive objects like galaxies cause space-time to bend around them, and if they are in the path of light rays, the rays will have to take different paths to bend around them as well. The rays then converge on the other side as one focused ray

What is a “gravitational lens”?

Gravitational lensing is where the gravity of a massive object amplifies electromagnetic radiation.

Albert Einstein’s theory of relativity states that gravity is not a force, but rather a warp in spacetime due to the presence of mass or energy.

If you think of the elongated leaf as space-time, and the watermelon as a representation of mass, then dropping the watermelon on the leaf will cause the latter to curve around it.

As a result, bodies with less mass move towards the denser body along this curve, and it manifests itself in the form of a gravitational force.

Light is also affected by this bending, as the massive object in its path causes each ray to take a different path and bend around it.

Then all the rays converge at a focused point on the opposite side of the body as a single, magnified beam that can be easily detected by telescopes.

Signs of hydrogen in the outer reaches of the universe are notoriously hard to come by.

The waves produced by hydrogen atoms often have long, low-energy wavelengths, making them unlikely to survive the long trip to our telescopes.

To date, it was the oldest hydrogen emission ever detected 4.4 billion years age or old

But this last signal took advantage of a phenomenon called “gravitational lensing,” which focused the rays and allowed them to be detected.

Albert Einstein’s theory of relativity states that gravity is not a force, but rather a warp in spacetime due to the presence of mass or energy.

If you think of the elongated leaf as space-time, and the watermelon as a representation of mass, then dropping the watermelon on the leaf will cause the latter to curve around it.

As a result, bodies with less mass move towards the denser body along this curve, and it manifests itself in the form of a gravitational force.

The larger the object, for example a star, black hole, or galaxy, the more space-time warps and the stronger its gravitational pull.

Light is also affected by this bending, as the massive object in its path causes each ray to take a different path and bend around it.

Then all the rays converge into a single focused beam on the other side of the object that is easy to detect with telescopes.

Co-author Dr Nirupam Roy, from the Indian Institute of Science, said: ‘Gravitational lensing amplifies the signal coming from a distant object to help us look into the early universe.

'In this specific case, the signal is bent because there is another massive object, another galaxy, between the target and the observer,' said co-author Dr. Nirupam Roy.  This effectively magnifies the signal by a factor of 30, allowing the telescope to pick it up.  Pictured: An image of a foreground galaxy captured by the Hubble Space Telescope zooming in on the light from SDSSJ0826+5630

‘In this specific case, the signal is bent because there is another massive object, another galaxy, between the target and the observer,’ said co-author Dr. Nirupam Roy. This effectively magnifies the signal by a factor of 30, allowing the telescope to pick it up. Pictured: An image of a foreground galaxy captured by the Hubble Space Telescope zooming in on the light from SDSSJ0826+5630

In this specific case, the signal is bent by the presence of another massive object, another galaxy, between the target and the observer.

This effectively magnifies the signal by a factor of 30, allowing the telescope to pick it up.

Physicists have been able to gather information about hydrogen gas in the source galaxy from the signal.

In their paper published this month in Monthly Notices of the Royal Astronomical SocietyThey say the atomic mass of the gas in SDSSJ0826+5630 is about twice the atomic mass of stars visible from Earth.

They also hope that the discovery of such an ancient emission of hydrogen means more may be on the horizon, and results in a better understanding of the universe.

“A galaxy emits different types of radio signals,” said Dr Chakraborty.

Until now, it was only possible to pick up this particular signal from a nearby galaxy, which limits our knowledge of those galaxies closest to Earth.

But with the help of a naturally occurring phenomenon called gravitational lensing, we can pick up a faint signal from a record distance.

This will help us understand the formation of galaxies at much greater distances from Earth.

The study claims that aliens have not yet contacted Earth because there is no sign of intelligence here

If aliens really do exist, why haven’t they already tried to contact us?

The idea of ​​intelligent extraterrestrial life has long intrigued scientists and the public alike, with many theories as to what may or may not be out there in the depths of space.

A recent study has now offered a new explanation for why aliens haven’t visited our planet – because there is no sign of intelligence here.

In essence, they mean that we have only been sending detectable signals from space since the 1930s, so aliens have not had that long to receive or respond to the message.

Read more here