15 years… that’s how long it took astronomers to hear our universe hum for the first time. They succeeded by using large telescopes and dead stars. Hundreds of scientists from all over the world have contributed to this major breakthrough. But what exactly have scientists discovered? How did they do that? And what does this mean for us? Science journalist Martijn Peters explains.
“The scientists have discovered gravitational waves,” Peters begins. “To be more specific, they’ve heard the echoes of it buzzing. A kind of background noise from our universe. Such a gravitational wave is a wrinkle in space-time that arises during extremely energetic and violent events in our universe. For example, the collision of two black holes. You can compare that collision a bit with throwing a stone into a pond. Those waves then travel through our universe at the speed of light.”
Albert Einstein predicted the existence of these gravitational waves as early as 1916, but it took nearly 100 years for scientists to observe them and prove their existence. “In 2015, astronomers observed such a gravitational wave for the first time. So what is so new about this discovery? Well, that was a short wave gravitational wave back then, just a few thousand miles long. So easier to observe. But now they’ve heard the hum of gravitational waves that are light-years across, the ones with long wavelengths.”
Read more below the image.
“When you know how gigantic our universe is, you might wonder why our universe isn’t a constant hum of gravitational waves caused by all sorts of things going on in it. The fact that we cannot observe this is because our earth is simply too small. You won’t detect those light-years-wide gravitational waves with the instruments we have now.”
And so the scientists came up with a genius idea. “They used dead stars, pulsars. These are neutron stars that rotate at lightning speed and emit light in the process,” Peters explains. “They are, as it were, gigantic lighthouses in our galaxy from which you know exactly when to expect a flash of light. But when such a ripple in space-time comes between us and the pulsar, it suddenly causes a change in the duration of the flashes.”
Read more below the image.
The scientists used dozens of those pulsars to build a gigantic telescope the size of our Milky Way that finally showed the fingerprint of those long-wavelength gravitational waves. “It is fantastic that with our ingenuity we can now listen to the symphonic orchestra of our universe with dead stars.”
“This new discovery opens up a whole new world for us. It gives us the opportunity to learn all kinds of new things about our universe, such as the life course of galaxies such as our Milky Way. Long-wavelength gravitational waves can be caused by a variety of events. From the merger of supermassive black holes to the rapid expansion of space after the Big Bang. In one fell swoop we now look at the universe in a completely different way.”
Mars through UV glasses: our red planet has never looked so alien
The search for extraterrestrial life is back in full swing. But how do scientists start such a thing? “Perhaps our view is much too narrow” (+)
LOOK. Shocking NASA video makes CO2 emissions visible
Free unlimited access to Showbytes? Which can!
Log in or create an account and don’t miss a thing of the stars.