After 15 years of collecting data using the world’s largest radio telescopes (and using a virtual observatory the size of our galaxy), researchers at the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) have unveiled an impressive find: the detection of a cosmic background (a murmur miraculously perceptible) of gravitational waves associated with the most violent events in the universe.
They have found out how to see the screen of the cosmos in which events of such a dimension took place, which until today have not even been narrated in mythology.
Where does the detected murmur come from?
According to the study authors, these subtle ripples to our technological ears may be caused by the merger of supermassive black holes (with masses up to billions of times that of our Sun) as they began to spin rapidly around each other. Another hypothesis suggests its formation during the universe inflation chapterabout a billion years after the Big Bang.
To identify them, scientists have relied on the effect nano tiny that produce some extraordinary cosmic objects: the press.
The pulsars are clocks extraordinarily accurate astrophysicists and serve as peculiar metronomes cosmic. They are remnants of dead stars that rotate at high speed, emitting a radio pulse with each turn. By spinning so quickly (and positioning itself in our line of sight), an observer on Earth perceives a beam that repeats thousands of times per second, allowing time to be measured with a precision greater than that of an atomic clock.
The fabulous finding has been that gravitational waves produce an inadmissible effect on them for a watchmaker: they slow down or advance their rotation.
Until 2015, objects in the cosmos were studied based on the electromagnetic radiation they emitted, in visible light, infrared or radio waves, among other components of the electromagnetic spectrum. Since then we are not only able to see them (electromagnetic waves) but also of hear to the stars, thanks to the detection of gravitational waves. now we can hear his murmur.
a magical moment
Scientist Maura McLaughlin (of the US network Pulsar Search Collaboratory), referred to the new discovery as a “magical moment.”
Although the scientific community was already aware of specific gravitational wave signals (such as those detected by LIGO and Virgo), this is now the first time that a cosmic background of gravitational waves has been recorded: a kind of whisper coming from all directions and associated with the most energetic events in the universe.
The consortium’s network of radio telescopes from Europe, North America, India, Australia and China Pulsar International Sync Matrix (IPTA) studied the ticking rates of 67 pulsars throughout our galaxy for 15 years and found slight variations in the timing of their radio pulses.
The consortium has shown that the tiny temporal variations found in these cosmic clocks (of up to a billionth of a second in more than 20 years) are due to the passage of low-frequency gravitational waves (and wavelengths of light-years). These distort the space between Earth and the pulsars themselves. As a consequence, radio pulses arrive at ground-based observatories earlier or later than expected. : the cosmic background of gravitational waves.
The importance of this new finding
For now, this international team has managed to measure the general background of gravitational waves, but it cannot distinguish one by one the sources that compose it. according to NASA explains«Detecting the background noise of gravitational waves is similar to listening to the hum of a large group of people talking at a party, but without distinguishing any particular voice.»
Hopefully in the not too distant future we will be able to distinguish each of these voices of the most primitive and violent universe (who knows if the ecological of the Big Bang). In the meantime, let’s enjoy this new find, a truly magical moment in the form of murmur cosmic.