Menorcan Alicia Sintes has spent decades, hoping that her science and physics can discover a phenomenon that when the surface of a neutron star is only a few millimeters high, “bumps” will appear. The tiny asymmetry in the star is enough to meet its needs, because it rotates thousands of times per second to produce an effect equivalent to that of ocean waves, but in the structure of space-time it is a gravitational wave.Kind of specific Time-space waveBorn from the wild rotation of a neutron star, it is Saintes’ dream.
Not yet implemented. However, many other gravitational waves have been detected during the five years of existence of the International LIGO Advanced Observatory. Hinters said: “It’s very fascinating.” He said that he will repeat it often in this interview. “Gravitational wave astronomy has pioneered another way of observing the universe, which will help answer thousands of questions and discover new phenomena that we can’t even imagine today.” Scientists and LIGO from the University of Balearic Islands The members added.
This week’s cooperation Ligao/Virgo Scientists announced an unexpected discovery of this type: The mass of a black hole is 142 times that of the sun, making it the largest black hole ever discovered. In addition, its birth (as observed by LIGO) occurred after the merger of two rare black holes (especially one of them), which is actually a “bug” in the catalog, which is an astronomical object, Its existence cannot be foreseen by theory.
Why did this discovery cause such a sensation?
We discovered a very interesting event, first of all because the merger of black holes led to the largest black hole we have, and we have never observed such an event. Then, because it made us reconsider our understanding of how black holes formed, it forced us to re-examine the model of star collapse.
When was it discovered?
We made an observation on May 21, 2019-yes, we spent a year analyzing the data-but it didn’t happen then, it was 7 billion years ago. Considering that the universe is 14 billion years old, this happened in the middle of its existence. At that time, the solar system did not exist, and there were no planets… It was fascinating. This is the most distant event we have detected so far.
Why does this discovery imply that they must modify the theory?
So far, all black holes we have observed have two types: stellar black holes, which have a mass of up to 100 times the mass of the sun; and supermassives, which are located in the center of the Milky Way galaxy and have a mass of 100,000 or more. We discovered 142 solar quality holes in the medium range for the first time. This is a new class. It is too large to be formed by the collapse of stars. This is how stellar black holes are formed.
However, the mystery also involves the parent black hole, which is one of 66 solar masses and the other is 85 solar masses.
Sintes is a tenured professor in the field of theoretical physics at the University of Balearic Islands and the head of the UIB Gravitational Physics Group. /Courtesy photo
Please explain how to form a stellar black hole.
When a very large star dies, a supernova explosion occurs, and then a black hole appears, which can hold up to 65 solar masses. If the original star is really very large, more than 200 solar masses, the model says that it will not have a supernova after death, but directly form a black hole, but it must be very large, exceeding 120 solar masses. Therefore, these models do not know how to explain the formation of black holes with solar masses between 65 and 120. The 66 depreciation rate of the adjusted model can still be explained. But 85 is more difficult.
Then, you have to look at models that describe star death and star collapse. But it could also be 85 solar masses, or a combination of both, which themselves are the product of the merger of two older black holes.
In other words, they are second-generation black holes.
That is. This discovery opened the door to some very good new explanations. It raises many questions, more interesting than those raised by covid-19.
They spent a year analyzing the data. Are they wrong?
will not. Before releasing the test results, we will analyze them and analyze them again, especially in unusual events like this.Also a few months ago jobs The signals observed with the telescope may correspond to our events, and the signals in the sky will correspond to what we see. If it is confirmed, there will be a lot to say.
Do you mean that the electromagnetic radiation emitted during the merger of two black holes will be detected?
By detecting gravitational waves, we are opening a new window for the universe, which is a new astronomical method.As a telescope [que detectan radiación electromagnética] They observe the same phenomenon as us, which is very exciting, and it provides us with a lot of information.This is what happened to us for the first time in 2017 and we can see Two neutron stars With many musical instruments, this is beautiful.
What happened now?
The data does not add up completely. They used a telescope to observe a flare from the accretion disk of a very distant galaxy. The flare is consistent with our direction detection, regardless of distance. But the error bar is large, so it may be large.
How many people participated in this discovery?
There are about 2,000 people in the LIGO/VIRGO cooperative organization, so it is impossible to determine how many people are involved in this particular work. This is a chain and everyone is important. It would be impossible without the work of the person who calibrated the instrument. I can say that UIB researchers Sascha Husa and David Keitel participated in the review of the article introducing this work, and the model developed at this university has been used with other groups to interpret the signal. .
Alicia Sintes and her partner Sascha Husa, also from UIB. /Courtesy photo
For a long time, the detection of gravity waves has been regarded as utopia. How many has been detected since LIGO went online?
Since 2015, in just five years, more than 60 have been detected. Every year is revolutionary. We will release the list of observations shortly until March last year, when the deadline for the event ended prematurely due to the flu pandemic.
It also affected them.
Of course, like everyone else. One of my doctoral students, Rodrigo Tenorio, went to the United States to work for three months, and only stayed on the detector for two weeks.
When can it be reopened?
Well, the next observation period is early 2022.
It is closed between observation periods for improvement. For example, increase the laser power, improve the vibration isolator…
What can be observed due to the improvement of the instrument?
We are just the beginning of what we can discover! This is a pop-up field that will answer many questions and open other questions. I have been waiting for twenty years to detect the gravitational waves generated by the rotation of neutron stars, pulsars in our own galaxy.
Does a rotating star produce gravitational waves?
So far, we have only observed waves produced by binary systems. A spinning neutron star may produce one, although it will be fainter. This happens only when the surface of a star with a diameter of about 12 kilometers is asymmetric. A small one is enough, almost only one millimeter high.
It would also be great to be able to observe the cosmic background of gravitational waves: we will see gravitational waves generated in the early universe when the universe was less than one millisecond, the so-called Planck time. Fascinating.