The most mysterious (known) star in the universe

Sagittarius A* is a massive black hole at the center of our Milky Way galaxy

For years, it was known as a strong source of radio signals, but there wasn't enough data to adequately describe or identify it. Orbital movements of nearby stars would indicate it had 4.6 million times the sun's mass, proving it was a black hole.

There are likely millions of small black holes lurking undetected near us in space

Because black holes are so hard to spot directly, astronomers rely on models of galaxy and star evolution to estimate their population. A recent study used simulations and galactic data to show that about 1% of all matter in the universe is locked inside black holes.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

How do scientists study far away stars?

Astronomy is the only science that is purely observational: meaning, scientists can't study stars in a lab. Here's a breakdown of how modern researchers use new tools to understand objects billions of light years away. As it turns out, the rules of science allow us to identify, categorize, and experiment with phenomena light years away.

Quantum mechanics-based technology may explain the Fermi paradox

It describes the discrepancy between the high likelihood of life beyond Earth given the vastness of the universe and the lack of evidence for such life, since extraterrestrial civilizations have not communicated with us. However, quantum communication—a more information-dense and effective method than classical means—requires massive receivers and very narrow signals, which would easily miss Earth, making a lack of signals expected.

Fly through the deepest image of space ever taken by the Hubble Space Telescope

Taken over 11 days between 2003 and 2004, when the space telescope was aimed at a seemingly empty patch of the sky, the Hubble Ultra-Deep Field revealed about 10,000 sources of light, most of which are entire galaxies. This visualization expands the 2D image into a 3D view spanning 12 billion years.

The mystery of the expanding universe

One of the most surprising discoveries about our universe over the past century is that it's expanding. Even more surprising is that it’s speeding up, and scientists aren’t entirely sure why. The rate should be roughly dependent on the total energy contained in the universe, but calculations keep coming up short. Explore the so-called “Hubble Tension,” along with potential candidates to solve the riddle.

Dark matter may be one of many hidden particles that don't interact with light

Theoretical candidates, such as axions and supersymmetric WIMPs, may open the door to a new branch of particle physics that shapes the cosmos through gravity. Some of these particles may constantly pass through us but interact too weakly to be detected.

Cloud 9 is a dark-matter-dominated failed galaxy

Identified in 2023, the starless, gas-rich object is the first of its kind seen by astronomers and provides a window into the early stages of galactic formation without observations relying on visible matter as a proxy. The existence of such REHLICs, or Reionization-Limited-H I Clouds, was predicted by cold dark matter cosmological models.

Explore our favorite visualization of the immense scale of space, from an astronaut to the size of the observable universe

See how distant aliens could preemptively strike humanity

Could aliens destroy us from light-years away? The team at Kurzgesagt imagines the impact of a highly sophisticated alien civilization setting out to crush humanity and considers the real-world logistics for warfare conducted across the Universe.

Neutron stars, the remains of some massive stars after they explode in a supernova, are the densest directly observable objects in the universe.

The sun is not as exceptional as once believed, but it remains rarer than most stars

Once believed to be the center of the universe, the sun is a G-class star, the same category to which about 6% of the Milky Way's stars belong. However, the sun is younger than 85%, more massive than 95%, and more metal-rich than about 93% of all stars. Unlike the sun, half of all stars also exist in multi-star systems.

Neutron stars, the remains of some massive stars after they explode in a supernova, are the densest directly observable objects in the universe.

As of 2025, scientific evidence strongly supports 3I/ATLAS being a comet

Claims of alien technology would require the celestial object to transmit measurable technological signals, which were not detected by the world's largest fully steerable radio telescope. Previous telescope observations identified that 3I/ATLAS's chemical composition, structure, and orbital characteristics are consistent with those of an interstellar comet.

Evidence for a ninth planet in our solar system

Is there a massive ninth planet on the edge of our solar system? Many of our solar system's most distant objects tend to swing out in one direction, hinting at evidence for a previously unknown ninth planet potentially larger than Earth. This theoretical planet's orbital period is estimated to be roughly 20,000 years, revolving around the sun at a distance of 60 billion miles. Experts break down the evidence in this quick video.

Neil deGrasse Tyson explains wormholes and black holes

Much of the film Interstellar is centered on the existence of a wormhole and black hole, which happen to be two of the most perplexing things in the universe. Astrophysicist and StarTalk Radio host Neil deGrasse Tyson explains how wormholes and black holes work in real life in this two-minute video.

The most bizarre numbers in the universe

Even for math-y types, some numbers are incomprehensible. This article dives into several kinds of numbers more complicated than even irrational numbers with endless decimals like "pi" or Euler's number: Noncomputable numbers. Read the bizarre...

Gaia mapped two billion stars in the Milky Way

Using geometric parallax, the European Space Agency mission made position measurements accurate to 2.78 × 10⁻¹⁰ degrees, revealing large-scale galactic structure and dynamics. Remnants of ancient galactic mergers were also identified within the Milky Way.

There may be as many as 300 million potentially habitable planets in our galaxy

The estimate comes from a study using data from the Kepler space telescope—a project aimed at finding exoplanets—and considers exoplanets similar in size to Earth around sun-like stars. These have a greater potential to possess liquid water.

The Oort cloud, our solar system's theoretical icy shell

Recurring comets lead astronomers to believe they originate from an extremely distant, icy shell encapsulating the solar system. They call it the "Oort cloud," and this giant swarm of icy objects is as fascinating as it is is massive. Home of comets and a tremendous number of planetesimals, this NASA site introduces you to the Oort.

Ten underrated astronomy studies from 2022

The James Webb Space Telescope understandably received a lot of coverage in 2022. This astrophysicist wants to highlight ten major studies published last year you might have missed.

View a gallery of Einstein rings

As light from a distant galaxy spreads in all directions, rays that pass around a massive object, such as another galaxy, may be bent around it. If the massive object is positioned between the distant galaxy and our telescopes, we may observe this deflected light forming a ring around it.

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.

What we know about the mysterious colossal squid

The colossal squid, the world's largest invertebrate, remained hidden from human discovery until nearly a century ago. Explore the world of the enormous and mysterious creature, including its features, habitat, and scientific significance. You can even plan a visit to the Museum of New Zealand Te Papa Tongarewa and marvel at a real-life display.

View the transparency of Earth's atmosphere and how it blocks most forms of light

The gases that make up Earth's atmosphere block most harmful forms of electromagnetic radiation from reaching the planet's surface, except for some ultraviolet light. Their transparency to radio waves means this form of light can reach Earth's surface, which is why most radio telescopes are ground-based rather than space-based.

The missing continent that took 375 years to find

It took scientists 375 years to discover the eighth continent of the world, which had been hiding in plain sight all along. But mysteries still remain.

English cosmologist Stephen Hawking (1942-2018) jokes about alien sightings

"I am discounting the reports of UFOs. Why would they appear to only cranks and weirdos?"

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

One disco producer saw 'Star Wars' four times on its opening weekend and was so inspired that he recorded the album 'Star Wars and Other Intergalactic Funk,' which produced a chart-topping single.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

Explore fun facts from the USPS, including unique post office buildings, a stamp that traveled past Pluto, and more.

In 1963, a basement renovation in Turkey revealed a passageway to a hidden, multilevel underground city that once housed as many as 20,000 people

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

In 2009, the nation was gripped by the story of a missing young boy who was believed to be floating over Colorado in a homemade balloon, until it was revealed that he was at home the whole time.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

Waves off the coast of Nazaré, Portugal, can reach over 100 feet and are caused by the area's deep underwater canyon geography

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.