Perpendicularity

Mercury will reach its greatest elongation - greatest distance from the sun - on April 21, 2025. Look east at dawn. It'll disappear from the morning sky in May. The post Look for Mercury farthest from the morning sun now first appeared on EarthSky.

Learn about the Oort cloud, a vast area beyond the inner solar system that is believed to contain icy objects arranged in a spiral shape.

Messier 77 is a well-known, relatively nearby, bright spiral galaxy with a supermassive black hole at its center.

My new article, "Quantum Entanglement of Optical Photons: The First Experiment, 1964–67," is intended to convey the spirit of a small research project that reaches into uncharted territory. The article breaks with tradition, as it offers a first-person account of the strategy and challenges of the experiment, as well as an interpretation of the final result and its significance. In this guest editorial, I will…

We would only see a fourth dimensional alien if it invaded our three-dimensional reality.

In the search for more efficient and sustainable energy generation methods, a class of materials called metal halide perovskites have shown great promise. In the few years since their discovery, novel solar cells based on these materials have already achieved efficiencies comparable to commercial silicon solar cells.

With the confirmation of gravitational waves less than a decade old, scientists are barreling ahead with new detectors to pick up ever more elusive ripples in spacetime

MIT Picower Institute scientists describe a new technology, called "multiline orthogonal scanning temporal focusing" (mosTF), that improves the clarity and speed of using two-photon microscopy to image synapses in the living brain.

How to do wall squats, a lower body gear-free exercise is a great starting point before moving on to heavyweight lower training.

Submillimeter wavelength radio observations of the Southern Ring Nebula have identified that it's actually a double ring, shaped by the interactions of three stars.

According to astronomers' best models of black hole evolution, the magnetic fields in the accretion disk need to be strong enough to push the accreting plasma around.

The start of spring is officially here. Here's everything to know about the season change, along with dates to mark on your calendar.

But they can look wildly different on other worlds.

The AR3590 solar region has grown to become the is the largest sunspot of the solar cycle and can be seen with eclispe glasses. The region was already a...

It turns out that rotating magnets can apparently create nearly physics-defying levitation.

Researchers at the University of Oxford in the UK have determined the true colors of Uranus and Neptune. They are much more similar than previously thought. The post True colors of Uranus and Neptune in newly processed images first appeared on EarthSky.

I'm currently writing a textbook on Electromagnetic Waves for my graduate optics students. I was reading up on zero refractive index materials for a chapter section and thought it would be fu…

Dec. 9 marks two years since the launch of the Imaging X-ray Polarimetry Explorer (IXPE), a joint NASA-Italian Space Agency mission to study polarized X-ray light – and the geometry and inner workings of the ultra-powerful energy sources from which it emanates.

On today's date in 1835 a newspaper claimed a famous astronomer had found life on the moon. The Great Moon Hoax was widely read and believed. The post The Great Moon Hoax of 1835: Would you have believed it? first appeared on EarthSky.

All you need to see one of the year's best meteor showers is a clear, dark sky—and patience