Prof. Kip Thorne, who was awarded the 2017 Nobel Prize in Physics, held a lecture on May 23rd 2018 in Schio, a small town near Venice, Italy. Almost 900 people were there. The Professor talked about gravitational waves, how it was possible to discover them, the history of LIGO and the new era of multi-messenger astronomy.
On February 12th 2016, most of the papers around the world reported “Einstein was right!”.
Considering that science very rarely makes the headlines, something big must have happened… that was indeed the case: on February 11th, 2016 the discovery of gravitational waves* was announced. Their existence was predicted by Einstein’s theory of relativity, however the great physicists thought they were so hard to measure it was likely they would never be discovered – after all, we’re talking about very small measurements…
> Take 1 cm
> Divide it by 100 and you get the diameter of a human hair.
> Split the human hair a million times and you get the size of an atom.
> Divide the atom by 100,000 and you get the measure of its nucleus.
> Divide the atomic nucleus 1000 more times and there it is: that’s the precision required to detect the first gravitational wave.
No wonder Einstein supposed it would be almost impossible to detect gravitational waves – who could imagine we’d be able to pick up such feeble signals?
Luckily someone believed we could do it: Prof. Kip Thorne is one of these people.
Who’s Kip Thorne? He’s an Astrophysicist who got the 2017 Nobel Prize in Physics for his research on gravitational waves. He’s also known for his cooperation with Christopher Nolan for Interstellar, in order to make the film scientifically accurate. I won’t go into details about his biography, since there’s Wiki.
Well, dear friends around the world, we Italians living near Venice had the honour to attend a lecture on gravitational waves held by Professor Kip Thorne himself.
I have to say one of our local communities of amateur astronomers (Gruppo Astrofili di Schio) deserves all the credit: they managed to perfectly organize this event in a special location called Teatro Astra.
Prof. Kip Thorne said he’s accepted to hold just two non-academic lectures in his life, the second one being at Teatro Astra.
This considered, Astrofili di Schio really deserve a huge thank you for inviting him. Especially because it was really worth it: everything the Professor said was absolutely mind-blowing.
Prof. Kip Thorne started off by putting things into perspective: the gravitational wave that travelled through our planet in September 2015 had just reached the outermost region of our galaxy when the Neanderthals were roaming the Earth.
In case you’re wondering why the announcement of the discovery of gravitational waves came only in February 2016, that’s because the team wanted to be absolutely sure the signal was not a false positive.
These waves originated from two colliding black holes – the one being 30 times and the other 35 times more massive than our Sun.
Gravity is the weakest of the four fundamental forces, so you’ll need massive objects to detect gravitational waves.
The event happened about 1 billion light years away from Earth.
The simple fact that we, little creatures, are capable of detecting signals so far in space and time really blows my mind. And this is the reason why I get a little bit emotional every time I look at those shiny dots in the sky we call stars.
The Professor pointed out, however, that observing light (i.e. electromagnetic waves) and detecting gravitational waves are two distinct processes – basically, because their nature is completely different.
Electromagnetic waves travel through space and time, while gravitational waves are spacetime itself being stretched and squeezed!
Moreover, electromagnetic waves are easily absorbed and dispersed, while gravitational waves are not. Also, unlike EM waves, they cannot be seen at all, not even with the most sophisticated telescopes.
So how did we come up with the right tools to discover gravitational waves?
Just like anything human beings create, it all started out with an idea.
The origin of a Noble Prize
Einstein theorised the existence of gravitational waves in 1916, however the idea of testing the theory came to Joseph Weber quite a few years later.
Prof. Weber spoke about this to Kip Thorne in 1963, while they were both sojourning in Les Houches, France (according to Prof. Thorne, one of the best places for a physicist to spend the holidays).
Unlike Einstein, the two physicists had additional information on which to base their reasoning: they were aware of the existence of black holes and technology had made giant leaps forward since the early 1900s.
Prof Thorne also explained how we got to the discovery of gravitational waves in September 2015: everything started out in 1966, when the Professor put together his research group at Caltech.
As an aside, he even admitted labelling Rainer Weiss’s project of gravitational wave detector as ‘not promising’ in one of his first papers – while it’s actually the basic model used for today’s gravitational wave detector**.
He certainly didn’t forget to mention the many experiments the group carried out throughout the 80s, which led to the building of LIGO. He also pointed out how difficult it was to get funds during the 90s and he expressed gratitude to Barry Barish and his important job in coordinating 50 people in the team (1200 today).
Where are we now?
Prof. Thorne couldn’t stress enough how remarkable the discovery of gravitational waves was, particularly in terms of what we’re going to do with it. It actually made it possible to open up the doors to a new era in astronomy, i.e. multi-messenger astronomy!
In August 2017, we detected the gravitational and electromagnetic wave coming from the collision of two neutron stars (a phenomenon called kilonova).
Unlike black holes, which do not emit light (otherwise they wouldn’t be called ‘black’, would they?), the detection of electromagnetic and gravitational waves at the same time gave us a new tool to better understand the universe. Like a sort of astronomical Rosetta Stone comparing the “new” and “old” way of doing astronomical research.
That’s exactly as important as it seems!
What about the future of Gravitational Waves?
I have to say, that was the most mind-blowing part of his speech.
We’re all looking forward to 2020, when the upgraded Advanced LIGO comes into action: the revamped LIGO will allow us to see 27 times more than we can see now!
It will be possible to detect gravitational waves around:
– neutron stars orbiting each other
– black holes tearing apart neutron stars
– supernova cores
… And we expect surprises!
If Prof. Kip Thorne says so, I guess we should believe him.
In addition to that, the equipment will be revised even further during the 2020s, getting 15 times more sensitive by 2030.
New projects and new technologies will allow us to understand the structure of black holes and maybe to see what’s inside. We could even be able to see the dynamics of spacetime – almost as if we were looking at our own universe from another dimension!
If this happens, I can’t wait to see reality exceed science fiction.
Words of wisdom
Almost 900 people were at Teatro Astra with me and I guess each and every one of us had at least one question to ask Prof. Thorne.
Given the short time available, the President of Gruppo Astrofili gathered in advance some questions from the pupils of the local school.
Answering one of these questions, he told us about the night in which he got the phone call from the Swedish Academy.
He was told he wouldn’t be surprised to know they decided to give the Nobel Prize in Physics to him, Rainer Weiss and Barry Barish for contributing to the discovery of gravitational waves.
Prof. Thorne confirmed he wasn’t surprised at all, in fact (smiling) he said he was expecting it!
However, at the same time, he was very disappointed with their choice: he believes it’s unfair to award the Nobel Prize to three physicists only, while over one thousand people all around the world made this discovery possible.
The Academy justified this decision by saying the Prize is a symbol meant to inspire everyone to achieve great things. Their opinion is that it’s easier to see yourself following the path of one individual rather than a group.
On the contrary, Prof. Thorne pointed out it is important to tell everyone that the best achievements are possible only when people work as a team.
I couldn’t agree more. It was a humble thing to say, and a life lesson.
Sometimes our own ego pushes us so hard it makes us forget that cooperation is the most efficient way to go further.
As humans, we’ve always shown we can overcome our own limits. People have rarely made breakthroughs as individuals, though.
I think this should not be underestimated.
In the end he was asked what piece of advice he could give to a young boy or girl who’d like to start a career in science. His answer was simply to find a work “that’s like play”!
He admitted his job is not always easy, but he clearly said the reason why he kept going is because it’s so much fun.
It is a common misconception to think about scientists as sort of cold data analysts, while it is just the opposite.
After all, we can only reach our goals if we’re passionate about what we do.
It was nice to see young boys and girls ask Professor Thorne for an autograph as if he were a Rock star.
We don’t often realise how important people like him have been to the progress of humanity.
Electricity for our smartphones, the medicines we take when we’re ill, means of transport that take us to places our legs would never reach… We take these things for granted, but, if we think about it, we have the privilege of having them because of some people’s primordial curiosity.
I’m not saying we should thank scientists and scientists only if today we live healthier and longer lives than our ancestors – in fact I do believe Art is one of the best ways for us to improve our lives.
However, I think we should be more grateful to men and women of science than we (as a society) generally are.
Scientific reasoning made us live long and prosper.
* I won’t spend much time talking about what gravitational waves are and how it was possible to detect them, because the world wide web has plenty of articles to offer: my favourite is this one by Phil Plait, who is always a joy to read.
** actually, Rainer Weiss received the 2017 Nobel Prize in Physics together with Barry Barish and Kip Thorne. Well, everybody makes mistakes!