Blackholes are a breakdown in the equations of spacetime. This means both space and time no longer behave the way we would expect of them. Today we explore the breakdown in time around blackholes and what it means to interact with the event horizon, or the place where time appears to stand still.
Further Reading/Consumption:
Black holes & time warps: einstein’s outrageous legacy — kip thorne.
Your Daily Equation #31: BLACK HOLES: And Why Time Slows Down When You Are Near One — https://youtu.be/qph51qUgwgU
What happens to you if you fall into a black hole? — https://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/fall_in.html.
Physics Beyond the Event Horizon — https://knotphysics.net/black-holes
Do you know what the Earth’s atmosphere is made of? You’d probably remember it’s oxygen, and maybe nitrogen. And with a little help from Google you can easily reach a more precise answer: 78% nitrogen, 21% oxygen and 1% Argon gas. However, when it comes to the composition of exo-atmospheres—the atmospheres of planets outside our solar system—the answer is not known. This is a shame, as atmospheres can indicate the nature of planets, and whether they can host life.
As exoplanets are so far away, it has proven extremely difficult to probe their atmospheres. Research suggests that artificial intelligence (AI) may be our best bet to explore them—but only if we can show that these algorithms think in reliable, scientific ways, rather than cheating the system. Now our new paper, published in The Astrophysical Journal, has provided reassuring insight into their mysterious logic.
Astronomers typically exploit the transit method to investigate exoplanets, which involves measuring dips in light from a star as a planet passes in front of it. If an atmosphere is present on the planet, it can absorb a very tiny bit of light, too. By observing this event at different wavelengths—colors of light—the fingerprints of molecules can be seen in the absorbed starlight, forming recognizable patterns in what we call a spectrum. A typical signal produced by the atmosphere of a Jupiter-sized planet only reduces the stellar light by ~0.01% if the star is Sun-like. Earth-sized planets produce 10–100 times lower signals. It’s a bit like spotting the eye color of a cat from an aircraft.
Astronomers may have seen the light from two black holes smashing into one another for the first time ever.
Black holes are completely dark and therefore invisible to light-detecting telescopes. So far, the only way astronomers have been able to “observe” black holes colliding is by detecting the resulting gravitational waves.
A group of researchers has outlined a surprisingly simple method for recreating the conditions near a neutron star, a breakthrough that could lead to new unimagined scientific discoveries revolving around the mysterious role of antimatter, a report from New Atlas explains.
The team of physicists designed a device, detailed in a paper in the journal Communications Physics, that fires two lasers at each other. The result is that the energy from the two lasers is simultaneously converted into matter, in the form of electrons, as well as antimatter, in the form of positrons.
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Everything we do as living organisms is dependent, in some capacity, on time. The concept is so complex that scientists still argue whether it exists or if it is an illusion. In this video, astrophysicist Michelle Thaller, science educator Bill Nye, author James Gleick, and neuroscientist Dean Buonomano discuss how the human brain perceives of the passage of time, the idea in theoretical physics of time as a fourth dimension, and the theory that space and time are interwoven. Thaller illustrates Einstein’s theory of relativity, Buonomano outlines eternalism, and all the experts touch on issues of perception, definition, and experience. Check Dean Buonomano’s latest book Your Brain Is a Time Machine: The Neuroscience and Physics of Time at https://amzn.to/2GY1n1z.
TRANSCRIPT: MICHELLE THALLER: Is time real or is it an illusion? Well, time is certainly real but the question is what do we mean by the word time? And it may surprise you that physicists don’t have a simple answer for that. JAMES GLEICK: Physicists argue about and physicists actually have symposia on the subject of is there such a thing as time. And it’s also something that has a traditional in philosophy going back about a century. But, I think it’s fair to say that in one sense it’s a ridiculous idea. How can you say time doesn’t exist when we have such a profound experience of it first of all. And second of all we’re talking about it constantly. I mean we couldn’t get, I can’t get through this sentence with out referring to time. I was going to say we couldn’t get through the day without discussing time. So, obviously when a physicist questions the existence of time they are trying to say something specialized, something technical. BILL NYE: Notice that in English we don’t have any other word for time except time. It’s unique. It’s this wild fourth dimension in nature. This is one dimension, this is one dimension, this is one dimension and time is the fourth dimension. And we call it the fourth dimension not just in theoretical physics but in engineering. I worked on four dimensional autopilots so you tell where you want to go and what altitude it is above sea level and then when you want to get there. Like you can’t get there at any time. GLEICK: Einstein or maybe I should say more properly Minkowski, his teacher and contemporary, offers a vision of space-time as a single thing, as a four dimensional block in which the past and the future are just like spatial dimensions. They’re just like north and south in the equations of physics. And so you can construct a view of the world in which the future is already there and you can say, and physicists do say something very much like this, that in the fundamental laws of physics there is no distinction between the past and the future. And so if you’re playing that game you’re essentially saying time as an independent thing doesn’t exist. Time is just another dimension like space. Again, that is in obvious conflict with our intuitions about the world. We go through the day acting as though the past is over and the future has not yet happened and it might happen this way or it might happen that way. We could flip a coin and see. We tend to believe in our gut that the future is not fully determined and therefore is different from the past. DEAN BUONOMANO: If the flow if time, if our subjective sense of the flow of time is an illusion we have this clash between physics and neuroscience because the dominant theory in physics is that we live in the block universe. And I should be clear. There’s no consensus. There’s no 100 percent agreement. But the standard view in physics is that, and this comes in large part from relativity, that we live in an eternalist universe, in a block universe in which the past, present and future is equally real. So, this raises the question of whether we can trust our brain to tell us that time is flowing. NYE: In my opinion time is both subjective and objective. What we do in science and engineering and in life, astronomy, is measure time as carefully as we can because it’s so important to our everyday world. You go to plant crops you want to know when to plant them. You want to know when to harvest them. If you want to have a global positioning system that enables you to determine which side of the street you’re on, from your phone you need to take into account both the traditional passage of time that you might be familiar with watching a clock here on the Earth’s surface, and the passage of time as it’s affected by the… Read the full transcript at https://bigthink.com/videos/does-time-exist
When physicist Tyler Cocker joined Michigan State University in 2018, he had a clear goal: build a powerful microscope that would be the first of its kind in the United States.
Having accomplished that, it was time to put the microscope to work.
“We knew we had to do something useful,” said Cocker, Jerry Cowen Endowed Chair in Experimental Physics in the College of Natural Science’s Department of Physics and Astronomy. “We’ve got the nicest microscope in the country. We should use this to our advantage.”
A new analysis of the South Pole-based telescope’s cosmic microwave background observations has all but ruled out several popular models of inflation.
Physicists looking for signs of primordial gravitational waves by sifting through the earliest light in the cosmos – the cosmic microwave background (CMB) – have reported their findings: still nothing.
But far from being a dud, the latest results from the BICEP3 experiment at the South Pole have tightened the bounds on models of cosmic inflation, a process that in theory explains several perplexing features of our universe and which should have produced gravitational waves shortly after the universe began.
Physicists are interested in the big questions like “Where did we come from?” and “What is all this stuff?”. But the answers to some of these questions, just lead to more questions.
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When we look into the night sky, we see the universe as it once was. We know that in the past, the universe was once warmer and denser than it is now. When we look deep enough into the sky, we see the microwave remnant of the big bang known as the cosmic microwave background. That marks the limit of what we can see. It marks the extent of the observable universe from our vantage point.
The cosmic background we observe comes from a time when the universe was already about 380,000 years old. We can’t directly observe what happened before that. Much of the earlier period is fairly well understood given what we know about physics, but the earliest moments of the big bang remain a bit of a mystery. According to the standard model, the earliest moments of the universe were so hot and dense that even the fundamental forces of the universe acted differently than they do now. To better understand the big bang, we need to better understand these forces.
One of the more difficult forces to understand is the weak force. Unlike more familiar forces such as gravity and electromagnetism, the weak is mostly seen through its effect of radioactive decay. So we can study the weak force by measuring the rate at which things decay. But there’s a problem when it comes to neutrons.