“I was speaking to a friend [who’s] an economic analyst, and his personal definition of a truth was when something’s 51%+ likely to happen… In science, do you ever truly accept anything as a truth, and if so, on what grounds do you typically decide its worthy of being called “true”?“
You might be used to the colloquial way we speak about things being true. It’s either true or it’s false. The truth is something that’s absolute, and something that’s untrue is either a lie, an ignorant statement, or something that’s simply not right. But in science, what we speak of as a scientific truth isn’t absolute at all.
All scientific truths are nothing more than provisional: they are our best approximations of reality. They have a range of validity over which they can be applied to give quantitatively correct predictions, and that range is finite and limited. Step outside of it, and you’ll find exactly where that scientific truth breaks down. When that happens, don’t despair, but rejoice!
“Now that the effect of vacuum birefringence has been observed — and by association, the physical impact of the virtual particles in the quantum vacuum — we can attempt to confirm it even further with more precise quantitative measurements. The way to do that is to measure RX J1856.5-3754 in the X-rays, and measuring the polarization of X-ray light.
While we don’t have a space telescope capable of measuring X-ray polarization right now, one of them is in the works: the ESA’s Athena mission. Unlike the ~15% polarization observed by the VLT in the wavelengths it probes, X-rays should be fully polarized, displaying right around an 100% effect. Athena is currently slated for launch in 2028, and could deliver this confirmation for not just one but many neutron stars. It’s another victory for the unintuitive, but undeniably fascinating, quantum Universe.”
If you think about empty space at a quantum level, you’ll find that it isn’t so empty, after all. Due to the inherent effects of quantum uncertainty, particle/antiparticle pairs pop into and out of existence continuously, including electrically charged particles. If you look at the quantum vacuum in the presence of a strong enough external magnetic field, the positive and negative particles, even though they’re only virtual particles, will move differently, and therefore will affect the real particles that pass through them differently than if there were no magnetic field. This leads to a real, observable signal that can be seen in space: around neutron stars!
“Korolev began designing the Soyuz spacecraft that would carry crews to the Moon, as well as the Luna vehicles that would land softly on the Moon, plus robotic missions to Mars and Venus. Korolev also sought to fulfill Tsiolkovsky’s dream of putting humans on Mars, with plans for closed-loop life support systems, electrical rocket engines, and orbiting space stations to serve as interplanetary launch sites.
But it was not to be: Korolev entered the hospital on January 5, 1966, for what was thought to be routine intestinal surgery. Nine days later, he was dead from colon cancer complications. Without Korolev as the chief designer, everything went downhill quickly for the Soviets. While he was alive, Korolev fended off attempted meddling from designers like Mikhail Yangel, Vladimir Chhelomei, and Valentin Glushko. But the power vacuum that arose after his demise proved catastrophic.”
On July 20th of this year, humanity will celebrate the 50th anniversary of the first human footsteps on the surface of another world: the Moon. Yet history could have been vastly different had one man in the Soviet space program, Sergei Korolev, not suddenly died. The mastermind behind Soviet rockets and most of the major successes of the 1950s and early-to-mid 1960s, Korolev had plans to have humans orbit the Moon in 1967 and land on it in 1968. It’s interesting to think that the USA didn’t take the lead as much as the Soviets lost it, and that’s largely due to the death of one man alone.
“If you have an astrophysical object that emits radiation, that immediately defies the definition of black: where something is a perfect absorber while itself emitting zero radiation. If you’re emitting anything, you aren’t black, after all.
So it goes for black holes. The most perfectly black object in all the Universe isn’t truly black. Rather, it emits a combination of all the radiation from all the objects that ever fell into it (which will asymptote to, but never reach, zero) along with the ultra-low-temperature but always-present Hawking radiation.
You might have thought that black holes truly are black, but they aren’t. Along with the ideas that black holes suck everything into them and black holes will someday consume the Universe, they’re the three biggest myths about black holes. Now that you know, you’ll never get fooled again!”
So, you thought you knew all there way to know about black holes? That if you get enough mass together in a small enough volume of space, you create an event horizon: a region from within which nothing can escape, not even light. So how is it, then, that black holes wind up emitting radiation, even long after the last particle of matter to fall into them has ceased?
How does one get this idea [for the proof of Sylvester’s Theorem]? The answer is: I don’t know! It is like asking: How did Michelangelo do this?
“There are many people who would love to see Pluto regain its planetary status, and there’s a part of me that grew up with planetary Pluto that’s extraordinarily sympathetic to that perspective. But including Pluto as a planet necessarily results in a Solar System with far more than nine planets. Pluto is only the 8th largest non-planet in our Solar System, and is clearly a larger-than-average but otherwise typical member of the Kuiper belt. It will never be the 9th planet again.
But that’s not necessarily a bad thing. We may be headed towards a world where astronomers and planetary scientists work with very different definitions of what attains planethood, but we all study the same objects in the same Universe. Whatever we call objects — however we choose to classify them — makes them no less interesting or worthy of study. The cosmos simply exists as it is. It’s up to the very human endeavor of science to make sense of it all.”
Next month will mark 13 years since the International Astronomical Union (IAU) officially defined the term planet and ‘Plutoed’ our Solar System’s (up-until-that-point) 9th planet. With an additional 13 years of knowledge, understanding, data, and discoveries, though, did they get the decision right?
“By measuring the distorted light from distant galaxies behind a galaxy cluster, scientists can reconstruct the total cluster mass. In every galaxy cluster, the majority of the mass is outside of the galaxies: there is a huge dark matter halo. The intracluster gas, however, may be distributed differently, as normal matter can collide and heat up, emitting X-rays. But individual stars, ejected from galaxies, should trace the same path as the dark matter. In a cosmic first, scientists measured this intracluster light, and found it traces out the dark matter perfectly.”
If you want to know where the dark matter is located in the Universe, you had to infer its presence and abundance by measuring the gravitational effects it had on space. When it comes to large-scale structures, like galaxy clusters, this often involved exceedingly difficult reconstructions involving gravitational lensing, and relied on serendipitous alignments of observable background structures. But a new study has concocted an alternative method that works extremely well: just measure the intracluster light from stars that have been ejected from the component galaxies.
We know that the speed of electromagnetic radiation can be derived from Maxwell’s equation[s] in a vacuum. What equations (similar to Maxwell’s – perhaps?) offer a mathematical proof that Gravity Waves must travel [at the] speed of light?
If you were to somehow make the Sun disappear, you would still see its emitted light for 8 minutes and 20 seconds: the amount of time it takes light to travel from the Sun to the Earth across 150,000,000 km of space. But what about gravitation? Would the Earth continue to orbit where the Sun was for that same 8 minutes and 20 seconds, or would it fly off in a straight line immediately?
There are two ways to look at this puzzle: theoretically and experimentally/observationally. From a theoretical point of view, this represents one of the most profound differences from Newton’s gravitation to Einstein’s, and demonstrates what a revolutionary leap General Relativity was. Observationally, we only had indirect measurements until 2017, where we determined the speed of gravity and the speed of light were equal to 15 significant digits!
“It took the creation of over 400 million ϒ(4s) particles to detect time-reversal violation directly, and this was accomplished by the BaBar collaboration back in 2012. The test for the reversal of initial and final entangled states is, to date, the only direct test ever performed to see if T-symmetry is conserved or violated in a direct fashion. Just as anticipated, the weak interactions violate this T-symmetry, proving that the laws of physics are not identical whether time runs forwards or backwards.
In particle physics, the gold standard for experimental significance is a threshold of 5-sigma. Yet BaBar physicists achieved a significance of 14-sigma: a remarkable accomplishment. The reason you’ve likely never heard about it? It was overshadowed by slightly bigger particle physics news occurring in the same year: the discovery of the Higgs boson. But this result maybe Nobel-worthy, too. The laws of nature are not the same forwards and backwards in time. After seven years, it’s time the world felt the impact of this discovery.”
Imagine you took a ball and threw it off of a tower, watching its trajectory as it flew through the air and eventually hit the ground. If you were to take that same ball and throw it with the right speed and angle from the ground, it would fly through the air and wind up exactly at the point it was launched from in the first example. It would, in fact, follow the exact same trajectory as if you video recorded the first throw and ran the video backwards in time. This is called time-reversal invariance, and it’s valid for Newton’s laws of motion. But it isn’t valid for all laws of physics!