Earth is on average ten times closer to Mercury than Jupiter, but missions to both planets can take a similar amount of time to reach their science orbits. Why is that? (…) The energy our spacecraft needs to shed is on a completely different scale to using brakes to slow down

An unexpected superconductor was beginning to look like a fluke, but a new theory and a second discovery have revealed that emergent quasiparticles may be behind the effect. (…) Two papers published in the journals Nature and Science described (…) a three-layer graphene sandwich with the “bread” sheets aligned and the filling

It could happen to anyone. Maybe you're out trying to find a new habitable planet for the human race, or maybe you're just on a long walk and you slip. Whatever the circumstances, at some point we all find ourselves confronted with the age-old question: what happens when you fall

Why do stars twinkle? Our atmosphere is to blame as pockets of slightly off-temperature air, in constant motion, distort the light paths from distant astronomical objects. Atmospheric turbulence is a problem for astronomers because it blurs the images of the sources they want to study. The telescope featured in this

Welcome! In this post, we’ll be taking a character-by-character look at the source code of the BioNTech/Pfizer SARS-CoV-2 mRNA vaccine. (…) Now, these words may be somewhat jarring - the vaccine is a liquid that gets injected in your arm. How can we talk about source code? This is

In squash, it exists a perfect killing shot which is almost impossible to catch. It occurs when the ball hit an edge of the court. In this situation the ball exits at very low speed and rolls along the wall or the floor. With Caroline Cohen and Philippe Brunet, we

(…) You may have seen such meme images before. They are always pure click-bait garbage: “95% of MIT graduates couldn’t solve this!”, where “this” is some inane, or ill-defined, or trivial brain teaser. This one is not. The meme is a clever, or wicked, joke. Roughly 99.999995% of the

Ok, so you can’t really fire a vacuum optimized engine at sea level… and this, really, is where aerospikes come in. The idea behind aerospikes is you allow the ambient air pressure to actually form the walls containing the flow of the exhaust so it’s always in nearly

Loud sounds can harm our ears, especially if the noise appears all of a sudden. It's because the so-called acoustic reflex has not enough time to take effect. A car manufacturer has studied this phenomenon because drivers got ear injuries after car accidents. How could it better protect them? The

In any conventional silicon-based solar cell, there is an absolute limit on overall efficiency, based partly on the fact that each photon of light can only knock loose a single electron, even if that photon carried twice the energy needed to do so. But now, researchers have demonstrated a method

Boston University researchers, Xin Zhang, a professor at the College of Engineering, and Reza Ghaffarivardavagh, a Ph.D. student in the Department of Mechanical Engineering, released a paper in Physical Review B demonstrating it's possible to silence noise using an open, ringlike structure, created to mathematically perfect specifications, for cutting

The Lewis–Mogridge position, named after David Lewis and Martin J. H. Mogridge, was formulated in 1990 and observes that as more roads are built, more traffic consequently fills these roads. Speed gains from some new roads can disappear within months, if not weeks. Sometimes, new roads help to reduce

A few days ago, near my office, there was a promotional event for some random brand of cookies. You could get a box for free, but only if you picked a winning ball in the mouth of a dragon statue. I lost, but a friend shared its cookies. While crunching

In probability theory, the multi-armed bandit problem is a problem in which a fixed limited set of resources must be allocated between competing (alternative) choices in a way that maximizes their expected gain, when each choice's properties are only partially known at the time of allocation, and may become better

Experiments suggest that exotic superconducting materials share a “strange metal” state characterized by a quantum speed limit that somehow acts as a fundamental organizing principle. (...)The hypothesis is that electrons in strange metals might be “dissipating as quickly as they can consistent with the [Heisenberg] uncertainty principle,” Hartnoll explained. The

Present an argument or formula which (even barely) predicts what the next prime number will be (in any given sequence of numbers), and your name will be forever linked to one of the greatest achievements of the human mind, akin to Newton, Einstein and Gödel. (...)Since the death of Riemann

As reported in 1756 by Johann Gottlob Leidenfrost, volatile liquids on hot solids form “gleaming drops resembling quicksilver”, a consequence of their levitation on a vapour cushion.This makes the drops spectacularly mobile, moving away as soon as they are deposited—an observation commonly attributed to gravity or surrounding airflows.

Surprisingly few software engineers and scientists seem to know about it, [even if] it is such a general and powerful tool for combining information in the presence of uncertainty. (...)You can use a Kalman filter in any place where you have uncertain information about some dynamic system, and you can

Recent CERN experiments have once again validated a prediction of the standard model. This is embarrassing for scientists, as they are looking for experimental clues of limits of the standard model. Standard model is known not to explain everything.More about these alternative models below (source Wikipedia). Physics beyond the

Pulling on a knitted scarf can stretch it to twice its length, even though the thread it’s knitted from hardly elongates. Knitting is a timeworn craft, at least a thousand years old, but no satisfactory account of the mechanics of its stretchiness exists.New theoretical work describes how individual

Benham's top, also called Benham's disk, is named after the English newspaper-man, amateur scientist, and toymaker Charles Benham, who in 1895 sold a top painted with the pattern shown. When the disk is spun, arcs of pale color, called Fechner colors or pattern-induced flicker colors (PIFCs), are visible at different

Despite numerous studies and 30-plus genomes under their belts, scientists are still struggling to nail down the defining traits of these tall, long-lived, woody plants.https://www.knowablemagazine.org/article/living-world/2018/what-makes-tree-tree HN discussion https://news.ycombinator.com/item?id=16792726