What can cause a ripple in both space and time? Neutron stars colliding. And what can observe that phenomenon? A two-mile-long laser.
Michell Thaller, the Assistant Director of Science Communication at NASA, wanted to talk to us about a heavy subject matter. Specifically, super-dense neutron stars that are so dense that they're only the size of New York City but carry the weight of the sun. And when they circle each other in orbit for long enough, they collide with enough force to send ripples in both space and time. Those ripples alone are strong enough to alter the course of light. In fact, just a few years ago a rare astronomical event occurred where you'd have seen a star "blink" for a few minutes on and off before disappearing for good. Scientists are able to detect these gravitational ripples thanks to a LIGO, or a Laser Interferometric Gravitational-Wave Observatory, which measures the refraction of light based on gravity waves. Oh, and one more thing: Albert Einstein correctly deduced that this phenomenon years before it was ever recorded. If you'd like to know more, visit NASA.
This discovery finally points to the source of Earth's precious heavy elements, also proves Einstein correct in more ways than one.
Last September, scientists at a special observatory announced that they detected a gravitational wave for the first time. The detection took place in September, 2015, but wasn’t announced until last year. The observatory is known as the Laser Interferometer Gravitational-Wave Observatory (LIGO). It registered ripples in space-time formed from the collision of two black holes. Apparently, the fabric of the universe ripples just as water does.
We’ve tired the electromagnetic spectrum when it comes to examining the universe. Now, astronomers are fiddling with a whole new aperture, gravitational waves. A little over 100 years ago, Einstein first predicted gravitational waves as something that would happen throughout space-time as a result of dramatic events. September’s announcement proved him right, although he himself thought we’d never be able to detect them, the results being so slight.
Officials at the National Science Foundation, LIGO, MIT, Caltech, and other institutions have now made a second groundbreaking announcement, the detection of gravitational waves from another astronomical event, the merging of two neutron stars. This latest signal was detected on Aug. 17. A neutron star is the remnant of a larger star whose core has collapsed. Usually, this is followed by a supernova, where the outer layer of the star blows off in a colossal explosion.
The neutron stars that merged were each 1.1 to 1.4 times the mass of our sun. An event of this magnitude only occurs once in 80,000 years, LIGO scientists say. The light emitted by this neutron star collision resulted in a “fireball,” which is an intense burst of gamma radiation. Such a fireball or kilonova creates the heaviest known elements, such as gold, platinum, and lead, and sends them careening throughout the cosmos.
See an animated clip of a neutron star collision here:
These are small, dense stars. One teaspoon worth would weigh more than 10 million tons, more than the entire population of Earth. As the core continues to collapse, the gravity inside gets so strong it fuses protons and electrons together, forming neutrons, hence the name. When two neutron stars merge, one of two things happen. Either an even bigger neutron star is born or a black hole is made. This event, now known as GW170817, created an ultra-dense neutron star.
Though it occurred approximately 130 million years ago, the resulting gravitational waves reached Earth last August, with the ripples arriving one second before the light did. This is the very first time scientists recorded an astronomical event through both light and gravitational waves.
Over 1,200 scientists from 100 institutions around the world work at the LIGO Scientific Collaboration. LIGO is comprised of two observatories, one in Hanford, Washington, and the other in Livingston, Louisiana. Each contains an instrument so sensitive it can detect a single ripple in space-time lasting just a fraction of a second. In addition to the LIGO detectors, the newly launched Virgo observatory in Italy helped to zero-in on the location of the explosion. Other such observatories are in the works for Japan and India, which will further help pinpoint an event’s location.
Each observatory consists of an L-shaped tunnel. Laser light is sent by mirror down each of them. When there are no gravitational fluctuations, the laser bounces back normally. But when there are ripples in space-time, it squeezes and pulls the beam which gives scientists a reading.
Artist concept of neutron star falling into its neighbor. Credit: NASA
Caltech’s David H. Reitze is the executive director of the LIGO Laboratory. In a press release, he explained the importance of the groundbreaking even. “This detection opens the window of a long-awaited ‘multi-messenger’ astronomy. It’s the first time that we’ve observed a cataclysmic astrophysical event in both gravitational waves and electromagnetic waves — our cosmic messengers,” Dr. Reitze said, “Gravitational-wave astronomy offers new opportunities to understand the properties of neutron stars in ways that just can’t be achieved with electromagnetic astronomy alone.”
The event also solidified another of Einstein’s predictions. Not only does it further confirm the existence of gravitational waves but that they travel at the speed of light. Its little wonder that the scientists who put together LIGO won this year’s Nobel Prize in Physics.
See the announcement of this historic event in astronomy here:
These scientists scooped up the Nobel by detecting a ripple in space-time.
Officials in Sweden have just announced the 2017 Nobel Prize in Physics. Three American scientists won for detecting, for the very first time, gravitational waves or ripples in space-time, which were first predicted by Einstein back in 1916. Rainer Weiss of MIT, and Barry Barish and Kip Thorne of Caltech were this year’s recipients.
Weiss will receive half of the 9 million Swedish kronor ($1.1 million), and Barish and Thorne will split the rest. Their employment of advanced theory and the fabrication of the unique LIGO instrument won them the prestigious award, according to officials at The Swedish Royal Academy of Sciences.
LIGO stands for Laser Interferometer Gravity-Wave Observatory. There are two such sites in the US currently, one in Louisiana and the other in Washington State. The reason they’re 1,000 miles (1,609 km) apart is to better detect gravitational waves emanating from space. A third observatory called Virgo just came online in Italy, to join the collaborative project. LIGO alone has thousands of researchers from 20 different countries. Weiss said to reporters at the event, "I view this more as a thing that recognizes the work of a thousand people, a really dedicated effort that’s been going on for — I hate to tell you — as long as 40 years.”
A LIGO observatory is comprised of two, 2.5 mile (4 km) long tunnels set perpendicularly, like a big L. When a gravitational wave passes over Earth, the space in the tunnel gets compacted in one direction and stretched in another. This tiny fluctuation can be detected by laser. The instrument is so sensitive, it picks up fluctuations in space-time thousands of times smaller than the nucleus of an atom.
One of the tunnels at Virgo. Credit: Virgo Collaboration.
Gravitational observatories were first conceived 50 years ago. In the mid-70s, the laureates came together to try to construct what is now LIGO. Weiss had already designed a laser-based interferometer by then. What was particularly advantageous in his model is it filtered out certain unwanted background noise.
Rather than a straight line, Einstein theorized that space is curved and that tension between large bodies, such as Earth and the sun, effectively bend space-time. With extremely massive events, like a supernova or a black hole collision, gravitational waves are sent rippling throughout the universe at the speed of light. Where Einstein went wrong is that he thought since these waves are so minuscule, we’d never be able to detect them.
While we’ve explored the universe through instruments that detect cosmic rays, neutrinos, and electromagnetic radiation, gravitational waves offer an entirely new aperture in which to view the cosmos. According to the announcement’s press release, “This is something completely new and different, opening up unseen worlds. A wealth of discoveries awaits those who succeed in capturing the waves and interpreting their message.”
The LIGO observatory was first set up in 1999. In 2014, it received an upgrade, making it much more powerful. It first captured a ripple in space-time in 2015. This was the aftereffect of two black holes colliding, each 30 times the mass of our sun. The result was an even bigger black hole. The event occurred 1.3 billion light-years away. One light-year is about 5.9 trillion miles (9.5 trillion km). Ariel Goobar of the Royal Swedish Academy of Sciences compared LIGO to “when Galileo discovered the telescope.”
Thorne, speaking to the Associated Press by phone, called the wave detection "a win for the human race as a whole.” He added, “These gravitational waves will be powerful ways for the human race to explore the universe." Meanwhile, Barish called it "a win for Einstein, and a very big one."
Virgo is an important piece, since it allows researchers to better determine the location of the origin of ripples in space-time. More gravitational observatories are now being built. Scientists believe such facilities may allow us to find crucial particles never before discovered, such as those which may only exist in the vicinity of black holes.
To learn more details about how a laser-based interferometer works, click here:
Physics finds no trace of God so far—but does it matter?
Can God exist out there in space-time? Do the laws of nature support the idea of a divine creator, or do they rule it out? At the moment, the existence of a god is a deep question for theologists and philosophers: it won't become a scientific question until there is evidence of God. With so much uncertainty, the question Bill Nye likes to focus on instead is: how would that knowledge change your life? Is who you are, with and without religion, two different versions of your self? The reality is that you don't need evidence of any god to live a good life. For Nye personally, he goes by the moral framework of "be responsible for my own actions, and leave the world better than I found it." That's probably the surest way to protect the life of the people and the earth that we have, whether or not it was made by higher power.
Bill Nye's most recent book is Unstoppable: Harnessing Science to Change the World.
Time is this wild fourth dimension in nature, says Bill Nye. We depend on its neat measurements for survival – but subjectively it continues to elude us.
Our brains are terrible clocks. An hour can pass like a few minutes, a day can drag on for what seems like two. Because of that, we’re not always sure that time is real – is it just a label we’ve stuck onto the observed patterns of our universe? We can’t see, feel, or hear time, we can only see its effect on us and on things over the course of our lives. Bill Nye believes its both subjective and objective – there is something definitively measurable to time, and yet it’s so mysterious to our brains. Nye thinks (or hopes) that in his lifetime, a new discovery will be made about the nature of time and space-time that gives us some more answers about this curiosity-inducing fourth dimension. Bill Nye's most recent book is Unstoppable: Harnessing Science to Change the World.
Bill Nye's most recent book is Unstoppable: Harnessing Science to Change the World.