The Neil Gehrels Swift Observatory is a NASA spacecraft with telescopes designed to study gamma ray bursts—the most powerful explosions in the universe, which result from supernova explosions during the formation of neutron stars and black holes.

The deaths of massive stars and the mergers of neutron stars and black holes can produce gamma-ray bursts—jets of particles moving in opposite directions at near-light speed that comprise the universe's most powerful explosions.

LIGO is part of the advanced gravitational wave detector network

Like the Laser Interferometer Gravitational-wave Observatory, Europe's Virgo Gravitational Wave Interferometer and Japan's Kamioka Gravitational Wave Detector reflect laser beams down perpendicular tunnels to detect gravitational waves in the patterns created by the recombined waves. Future observatories are expected to contribute to this network, further improving gravitational wave detections.

Watch an artist's impression of two neutron stars merging in a kilonova explosion

Such an event produces enough light to briefly outshine an entire galaxy and to produce characteristic gravitational wave and gamma-ray signals. On August 17, 2017, these signals were captured by the LIGO–Virgo and Fermi/INTEGRAL observatories, respectively, from a kilonova about 130 million light-years away.

The European Space Agency is building a space-based gravitational wave observatory

The Laser Interferometer Space Antenna will consist of three spacecraft forming an equilateral triangle that will trail Earth as it orbits the sun. Lasers will travel 2.5 million kilometers along the sides of the triangle between these spacecraft to detect massive objects undergoing mergers or inspiraling, as well as speculative phenomena (e.g., cosmic strings).

View a gallery of neutron stars and related phenomena captured by Chandra

Launched on July 23, 1999, the Chandra X-ray Observatory is one of NASA's "Great Observatories" and has captured high-energy astronomical phenomena, including neutron stars and their surrounding nebulae, which are composed of the outer stellar layers expelled by their predecessors. Data from other observatories, including Hubble, help produce spectacular composite images.

During Nancy Roman's tenure as the agency's chief of astronomy, NASA launched Stargazer—the first successful space telescope—as part of the Orbiting Astronomical Observatory program.

Throughout its 10-year mission to create a time-lapse of the universe, the Vera C. Rubin Observatory will generate 500 petabytes of data by taking an ultrawide, ultra-high definition image every 34 seconds.

Read about the dangerous comet behind the Perseids meteor shower

Every summer, Earth passes through the debris trail of the Swift-Tuttle comet, producing the spectacle of the Perseids meteor shower. The phenomenon is a glorious opportunity for amateur stargazers, but astronomers have long noted the comet's orbit...

The Nancy Grace Roman Space Telescope—the first major NASA space telescope named after a woman—is expected to survey 12% of the sky in 17 months, a feat that would take the Hubble Space Telescope over a thousand years.

The next generation of space-based observatories

How exactly does a space telescope come to be funded by NASA? NASA's most famous telescopes, like Hubble and James Webb, were once featured in the decadal survey–a once per decade survey run by the National Academy of Science that recommends which projects to support. This article and podcast covers which telescope designs are in contention to be part of NASA's next generation of space-based observatories.

In 1997, the Compton Gamma Ray Observatory identified 'positron geysers'—fountains of antimatter particles—emerging from near the center of the Milky Way.

How neutron stars serve as laboratories for testing Einstein's theory of gravity

Data from a 16-year study of an orbiting pair of spinning neutron stars showed that measurements of gravitational wave energy and the bending of light around the system were consistent with predictions made by general relativity to an accuracy of at least 99.99% across seven tests. (Some readers may experience a paywall.)

In 1974, a pair of neutron stars provided the first evidence of gravitational waves

Observations of a pulsar—a rapidly rotating neutron star that emits light—revealed it to be part of a system of two stars that orbited one another in a shrinking orbit, indicating gradual energy loss. Calculations showed that the changing orbit was consistent with gravitational waves predicted to carry energy away from such a system.

LIGO made the first detection of gravitational waves

On February 11, 2016, scientists at the Laser Interferometer Gravitational-Wave Observatory announced the confirmed detection of ripples in spacetime, which were produced from the collision of two black holes 36 and 29 times the mass of the sun. The detection confirmed that gravitational waves travel at the speed of light, as predicted by Albert Einstein in 1915.

The first image of Sagittarius A*—the supermassive black hole at the center of the Milky Way Galaxy—was revealed in 2022, almost 50 years after its discovery.

The next generation of gravitational wave detectors may include a triangular design

The Einstein Telescope will use three pairs of underground detectors—each with arms separated by 60 degrees—arranged in an equilateral triangle. The European observatory will work alongside the Cosmic Explorer, a pair of new US detectors, to provide an eightfold increase in sensitivity over LIGO and extend the current detection frequency range.

View a simulated demonstration of how the Nancy Grace Roman Space Telescope will survey large portions of the sky to capture in 90 minutes what took three years for the Hubble Space Telescope.

Observations of colliding neutron stars by the Laser Interferometer Gravitational-Wave Observatory in 2017 confirmed that gravity travels at the speed of light.

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

Neutron star collisions may be the universe's gold factories

In his last broadcast interview, Stephen Hawking comments on detecting gravitational waves from the collision of neutron stars. The event may serve as a new means of measuring cosmological distances and help identify revisions to general relativity.

Gravitational waves—ripples in the fabric of spacetime—are detected at LIGO by measuring how two lasers traveling down equally distant, perpendicular tunnels interfere with one another after they reflect back and meet.

Since 2017, Virgo has helped LIGO localize astronomical phenomena

The detector near Pisa, Italy, coordinates its experimental runs with those in Hanford, Washington, and Livingston, Louisiana. Scientists can triangulate the locations of celestial events that generate gravitational waves using signal arrival times, just as earthquake locations can be determined from measurements at three seismic stations.

The first image of a black hole was created from an international telescope network

The Event Horizon Telescope united radio observatories worldwide to image the supermassive black hole at the center of the Milky Way, known as Sagittarius A*. The team couldn’t transmit their massive dataset online, so they physically flew hundreds of terabytes of data to MIT aboard airplanes.

Infrared vision gives Webb telescope access to the oldest light in the universe

To peer into the universe’s earliest moments, the Webb had to solve several immense engineering challenges: deploying a massive sun shield, surviving extreme cold, and stabilizing ultra-sensitive instruments. The telescope’s mirrors can adjust themselves in steps 10,000 times smaller than a human hair.

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

Watch the director's cut of the award-winning documentary about LIGO

Production on the film began in August 2015, shortly before the facilities detected gravitational waves for the first time on September 14. Those interviewed, including future Nobel Laureates Kip Thorne and Barry Barish, provide their accounts of the discovery as events unfold in real time.

The first interferometric gravitational wave detector was invented in 1972

Robert Weiss completed the designs after his students asked about an earlier apparatus that used stretched aluminum cylinders to detect passing gravitational waves. Unfamiliar with general relativity and hoping to keep the course focused on experimental tests rather than mathematics, Reiss later asked his students to consider his device for homework. (Some readers may experience a paywall.)

What are pulsars?

Pulsars are neutron stars created as part of stellar evolution and emit radiation beams visible from Earth. These beams pulse like a lighthouse's light due to the star's rotation, creating periodic high-energy emissions. Pulsars were first discovered as radio sources; it was also discovered they emit gamma rays. NASA uses its Fermi Gamma-ray Space Telescope to retrieve and analyze data from pulsars.

View the Crab Nebula in different wavelengths of light to identify the structures surrounding the neutron star—a stellar remnant composed of tightly-packed neutrons.

Why starquakes may explain various phenomena associated with neutron stars

Fast radio bursts—repeated millisecond-long pulses of enormous energy from neutron stars—are emitted with a timing that resembles the earthquakes and aftershocks seen on Earth when geological activity releases energy from within the planet. Although pulsars should gradually spin more slowly as they lose energy from emitting jets of radiation, sudden increases may result from interior matter moving during starquakes.

Between 2002 and 2025, upgrades have increased LIGO's detection range tenfold

After the construction of Initial LIGO was completed in 1999, no gravitational waves were detected during operations between 2002 and 2010. Instrument redesigns and significant technological improvements brought about Advanced LIGO, which began observations in 2015. Continued upgrades between continuous laser runs have improved detection sensitivity and stability.

Over a decade before the launch of the Hubble Space Telescope, Nancy Roman oversaw the Orbiting Solar Observatory program, which launched eight spinning spacecraft into low Earth orbit to study the sun.

The twenty-year effort to design the Webb's optics

Since its located 1 million miles from Earth, the Webb space observatory has to be able to repair itself—no Space Shuttles can be dispatched with astronaut engineers to repair it. That's why over two decades teams reiterated, cross-checked, and hyper-optimized the Webb's observing surface. Their efforts produced the world's largest space-based optical surface that is peering billions of years back in time. Learn the wild engineering of the telescope here.

Invisible to direct observation, scientists determined the object at the center of the Milky Way—Sagittarius A*—was a supermassive black hole based on the orbits of fast-moving stars in the area.

NASA's Near-Earth Object Surveyor can detect asteroids coming from the sun

Telescopes directed at the sun or lacking heat shields may become damaged, limiting our ability to monitor potentially dangerous objects coming from that direction. The NEO Surveyor is built to overcome this problem and spot asteroids that reflect as little as 5% of incoming light.

Explaining pulsars, the cosmic clocks and lighthouses of the universe

As of 2023, over 3,000 of these rapidly rotating neutron stars have been discovered, which contain magnetic fields along which energized particles accelerate and emit light, including X-rays, gamma rays, visible light, and, most commonly, radio waves. The fastest of these, PSR J1748–2446ad, rotates 716 times per second, meaning its surface equator moves at about 24% the speed of light.

The Hubble Space Telescope uses curved mirrors to collect and focus light

Classified as a Cassegrain reflector, the observatory bounces incoming visible light and some infrared and ultraviolet light off a primary mirror with a diameter of 2.4 meters. The reflected light is directed to a secondary mirror, which reflects it through a tiny hole in the primary mirror and onto detectors.

The 2017 Nobel Prize in physics was awarded to LIGO's founders

Rainer Weiss, Kip Thorne, and Barry Barish won the award for their contributions to the detector a year after the discovery of gravitational waves was announced. Acknowledging the Nobel statutes limited the prize to no more than three people, Thorne stated, "our marvelous discovery is the work of more than a thousand."

Cosmic rays are evidence of incredibly powerful astronomical events—solar cosmic rays provide information about eruptions and flares on the sun's surface, while galactic cosmic rays shed light on dying stars.

Scientists monitor volcanoes with a suitcase-sized observatory called SKATE

Short for Setup for the Kinematic Acquisition of Explosive Eruptions, the device is left to record heat, sound and visual data while volcanologists remain at a safe distance. The $58,000 tool is the successor to the FAMoUS (Fast Multiparametric Setup) prototype.

Space telescope development was driven by a desire to bypass Earth's atmosphere

The most important figure in the effort to create what would become the Hubble Space Telescope was Lyman Spitzer, who first proposed a telescope in orbit in 1946. The nearly 50-year endeavor led to space-based observatories, which are not limited by Earth's atmosphere absorbing or distorting most wavelengths of light.

Asteroids are often unobserved until they are days away from Earth

Even those large enough to cause local or regional damage are too small, dim, and far away to be observed readily from cosmological distances. New tools, like NASA's NEO Surveyor telescope, aim to address gaps in detection systems.

Bray Falls' astrophotography gallery

Bray Falls is a deep sky photographer out of Phoenix, Arizona, using his own set-ups to capture dazzling images of nearby galaxies and much more. Check out his images here.

Type Ia supernovae—explosions caused by the remnants of low-mass stars being reignited—brighten and dim so consistently that they are used as cosmic rulers to measure distances across the universe.

The James Webb Space Telescope is rewriting what we know about the early universe

Thanks to its advanced infrared sensors and massive mirror, the James Webb Space Telescope can see farther back in cosmic history than Hubble, revealing galaxies formed just 500 million years after the Big Bang.

When they merge, black holes release multiple solar masses of energy

The energy emanates outward in the form of gravitational waves, which can be detected at observatories like LIGO. After merging, it is impossible to determine the characteristics of the two black holes that merged to create it.

How a pulsar's properties led to the discovery of the first exoplanets

In 1992, astronomers examining the radio waves emitted by PSR B1257+12 as it swept past detectors every 0.006219 seconds noticed occasional deviations at regular intervals. Further analysis revealed the existence of two planets beyond our solar system orbiting the neutron star, causing it to wobble and affecting pulsar timing.

Webb Telescope zooms in on Orion Nebula and finds planet pairs

The Webb telescope has trained its infrared cameras on the nearest star-forming nebula in our universe, the Orion Nebula. Its images revealed a never-before-seen phenomenon: dozens of pairs of planet-sized objects in binary orbit, seemingly floating...

Take a tour of The Planetary Society headquarters with Neil deGrasse Tyson

Led by Bill Nye, the Hayden Planetarium director examines the LightSail aircraft, observes historical artifacts, such as a Mars meteorite, and explores props from the "Cosmos" TV series, which was hosted by Planetary Society cofounder Carl Sagan.

The discovery of neutron stars by Jocelyn Bell Burnell, who was not awarded the corresponding Nobel Prize

During her doctoral program in radio astronomy at Cambridge University, Bell Burnell's first two observations of a neutron star were initially dismissed as interference by Antony Hewish, her advisor. He and Martin Ryle, head of the research group, were jointly awarded the Nobel Prize in physics, the first awarded for astronomical research.