Stellar corpses can show us a universe in nanohertz code that we have never seen
Our body glows in the dark. In fact, it glows in the dark and in full sunlight, only our eye is not capable of detecting it. Luckily, we have developed technology to capture these elusive particles of light and translate them into something we can actually perceive. That is, for example, what night cameras do. They capture the light emitted by objects simply because they have a temperature (the moderate version of when something glows red hot). Some of our telescopes do the same, like the famous James Webb, which is capable of capturing the infrared, but even so, there is a lot of the universe that remains invisible to us. Light, for example, is not capable of showing us the first moments of the expansion of the universe, because it was still too dense to allow photons (particles of light) to travel through it. It is then where multi-messenger astronomy appears and, specifically, gravitational waves.
Light is not the only wave that crosses the cosmos bringing us information about its confines. Einstein already theorized the existence of gravitational waves, deformations of the very fabric of space-time that undulated like the wave that occurs when we shake the sheets on our bed. They are invisible waves, but we have been perceiving them thanks to very special telescopes for some years now. The fact is that, like light, we cannot detect them in their entire spectrum, not even with these telescopes.
Or, at least, that was what we thought, because a new scientific study has managed to expand the color palette with which we observe the universe. Now we can detect a type of gravitational waves that, until now, were “invisible” in practice.
Light waves are not always visible, the light that our eye captures belongs to what we call the “electromagnetic spectrum”, they are waves, like waves on the beach. Well, when these “waves” are separated by the appropriate distance, our eye captures them and we call them “visible spectrum”. All the colors we know are there. But, if the “waves” of light started to get closer to each other, we would have ultraviolet, X-rays and finally gamma rays. If they move away (which makes them less energetic), we reach infrared, which is what we emit, the same type of light with which the information from the remote to the television travels or the one used by elevators to open their doors if something happens.
If they move further away we will have microwaves and radio waves that we use, respectively, for those two technologies: microwaves and radios.
Well, gravitational waves can also be imagined as “waves” that are more or less close to each other and for now we are only good at capturing a specific frequency, large frequencies, but for a very specific reason. Although all asymmetric objects produce gravitational waves when they move, they are very weak. We need those objects to be truly huge so that their waves have the intensity that our technology can pick up, and that means talking about black holes and neutron stars.
The problem is that there is a relationship between the mass of an object and the frequency of its gravitational waves (how close their “waves” are), and these massive objects produce waves that are very far apart: very low frequencies, but this is another matter. problem. Without going into details, gravitational wave telescopes (interferometers) have to measure more than the distance between the “waves” of the wave they want to detect, so either by intensity or by wavelength , we are limited to both sides. However, that limitation is disappearing.
A group of researchers has published an article about it in the journal Research in Astronomy and Astrophysics. In it they explain that they have been observing 57 pulsars in regular periods for 41 months. To give us an idea, a pulsar is like a space lighthouse, a tremendously dense star corpse that rotates on itself at dizzying speeds, on the order of almost a thousand times per second. With each turn, its light flickers, and that change in brightness is surprisingly regular, like clockwork. Well, when a gravitational wave passes through a pulsar, it’s as if space-time (and what’s in it) stretches and contracts, like walking past a carnival mirror. It changes our size, and therefore, from our perspective, the blinking of the pulsar also changes its speed. This is how they have been detecting gravitational waves with a frequency much lower than what we have detected so far, on the order of nanohertz.
If these results are confirmed, we would be before the first detection of this type of gravitational waves and, therefore, it is as if we had one more color with which to see the universe. There would be sources of information that until now went unnoticed. However, despite the reliability of the results and the quality of the journal, scientists must be cautious and other teams will need to analyze this or similar data before issuing any verdict. Science may have given us a new eye with which to enjoy the universe, but it is too early to tell.