Featured series 
Tag: Harvard College Observatory (HCO)
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Science & Tech
Global warming is not so hot
Scientists at the Harvard-Smithsonian Center for Astrophysics took a look at how weather has changed in the past 1,000 years. They looked at studies of changes in glaciers, corals, stalagmites, and fossils. They checked investigations of cores drilled out of ice caps and sediments lying on the bottom of lakes, rivers, and seas. They examined…
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Science & Tech
Astronomers link gamma-ray bursts, supernovae
Gamma-ray bursts are incredibly bright flashes of high-energy radiation that likely signal the birth of black holes. Bursts occur at random locations scattered across the sky, and few last more than a minute, making them a challenge to study. A supernova is the explosion of a star at least eight times as massive as the…
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Science & Tech
Cool X-ray disk points to new type of black hole
Black holes are objects so dense and with a gravitational potential so strong that nothing, not even light, can escape the pull if it ventures too close. Black holes are invisible, yet the gas and dust falling into a black hole are heated to high temperatures and glow furiously. Scientists agree that there are at…
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Science & Tech
Harvard science historian publishes results of unprecedented 30-year census of Copernican masterpiece
First published in 1543, Nicholas Copernicus’ De revolutionibus orbium coelestium introduced the world to the concept of a sun-centered universe. In it, Copernicus detailed how the motions of the sun, moon, planets, and stars could be explained if the earth orbited the sun — a revolutionary idea. Starting in the 1970s, researcher Owen Gingerich began…
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Science & Tech
From cradle to grave
Astronomers have been using the Chandra X-ray Observatory and radio telescopes to observe two opposing jets of high-energy particles emitted following an outburst, first detected in 1998 by NASA’s Rossi X-ray Timing Explorer, from the double-star system XTE J1550-564. The X-ray jets, which require a continuous source of trillion-volt electrons to remain bright, were observed…
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Science & Tech
X-ray arcs tell tale of giant eruption
Scientists from the Harvard-Smithsonian Center for Astrophysics (CfA) report that two arc-like structures of multimillion-degree gas in the galaxy Centaurus A appear to be part of a ring 25,000 light years in diameter. The size and location of the ring suggest that it could have been produced in a titanic explosion that occurred about 10…
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Science & Tech
Even stars use sunscreen!
Mira variable stars are named after the red giant star Mira (omicron Ceti) in the constellation Cetus the Whale. Variable stars brighten, then dim, then brighten again. While astronomers have known of the existence of these dramatically changing stars for hundreds of years, the cause of their variability has been hard to identify. Now, two…
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Science & Tech
Chandra finds ghosts of eruption in galaxy cluster
Astronomers using NASA’s Chandra X-ray Observatory recently discovered relics of an ancient eruption that tore through a cluster of galaxies. The discovery implies that galaxy clusters are the sites of enormously energetic and recurring explosions, and may provide an explanation why galaxy clusters behave like giant cosmic magnets. Galaxy clusters are the largest known gravitationally…
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Science & Tech
Chandra captures Venus in a whole new light
Researchers using NASA’s Chandra X-ray Observatory have made the first X-ray images of Venus, Earth’s sister planet.
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Science & Tech
Chandra examines a quadrillion-volt pulsar
A pulsar is a rapidly spinning neutron star that emits massive amounts of radiation in rapid pulses that occur at regular intervals. A neutron star is created when the central part of a massive star collapses. The atoms in the star are crushed completely, and the electrons are jammed inside the protons to form a…
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Science & Tech
Chandra probes nature of dark matter
It’s one of the universe’s most enduring mysteries — what comprises the “dark matter” that scientists believe most of the universe is made of, but which humans have been unable yet to see? Scientists using the Chandra X-ray Observatory were able to precisely determine the distribution of dark matter in a distant galaxy cluster named…
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Science & Tech
Chandra catches Milky Way monster snacking
Researchers using the Chandra X-ray Observatory have, for the first time, observed the black hole at the center of our galaxy devouring material.
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Science & Tech
Chandra sees wealth of black holes in star-forming galaxies
Three independent teams of research scientists, including one from the Harvard-Smithsonian Center for Astrophysics, used NASA’s Chandra X-ray Observatory to find what they suspect are groups of mid-mass black holes in starburst galaxies. In a starburst galaxy, stars form and explode at an unusually high rate. The discovery could help explain the relationship among mid-mass…
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Science & Tech
Chandra reveals nest of tight binaries in dense cluster
Observations from a scientific team at the Harvard-Smithsonian Center for Astrophysics have revealed that an incredibly dense star cluster known as 47 Tucanae includes many binary stars. Most of the binary star systems in 47 Tucanae are systems in which a normal, Sun-like companion orbits a collapsed star, either a white dwarf or a neutron…
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Science & Tech
Chandra pinpoints edge of accretion disk around black hole
An object known as XTE J1118+480 is a black hole roughly seven times the mass of our Sun. XTE J1118+480 is locked in a close binary orbit with a Sun-like star. Recent observations by a team of scientists led by a researcher from the Harvard-Smithsonian Center for Astrophysics show an “accretion disk” around the black…
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Science & Tech
Gamma-ray astronomers detect “extreme” galaxies
Gamma rays from X-ray emitting galaxies seem to signal the existence of what astronomers are calling “extreme” galaxies. An international team of astrophysicists made the discovery of very-high-energy gamma rays, confirming the hypothesis of an Italian group that galaxies which emit strongly in the highest energy X-rays would also emit the most energetic gamma rays.…
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Science & Tech
Dark night sky tells us about structure and formation of solar system
The darkness of the night sky is one of astronomy’s great puzzles. An infinite universe uniformly filled with stars and galaxies should produce an infinitely bright night sky, Johannes Kepler concluded 400 years ago. So why is the sky dark? It has to do with the finite size of the Milky Way Galaxy and the…
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Science & Tech
Chandra X-ray Observatory helps put pieces together on gamma-ray bursts
Astronomers have long debated how gamma-ray bursts (or “GRBs”) originate. One theory contends that GRBs result when two “compact objects,” that is, neutron stars or black holes, collide and coalesce. Another theory speculates that a “hypernova,” a gigantic star collapsing on itself under its own weight, could cause these extremely energetic outbursts. An international team…
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Science & Tech
Chandra clinches case for missing-link black hole
Using NASA’s Chandra X-ray Observatory, scientists have zeroed in on a mid-mass black hole in the galaxy M82. This black hole – located 600 light years away from the center of a galaxy – may represent the missing link between smaller stellar black holes and the supermassive variety found at the centers of galaxies. The…
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Science & Tech
Cosmic ‘superbubbles’ bespeak toil and trouble
The merging Antennae Galaxies in constellation Corvus are producing massive bubbles of expanding X-ray-emitting gas at such astonishing rates that they are bumping into each other. Giuseppina Fabbiano, Andreas Zezas and Stephen Murray of the Harvard-Smithsonian Center for Astrophysics used NASA’s Chandra X-ray Observatory to capture in unprecedented detail this phenomenon. Fabbiano said that the…
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Science & Tech
Chandra discovers elusive ‘hot bubble’ in planetary nebula
A planetary nebula (so called because it looks like a planet when viewed with a small telescope) is formed when a dying red giant star puffs off its outer layer, leaving behind a hot core that will eventually collapse to form a dense star called a white dwarf. According to theory, a “hot bubble” is…
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Science & Tech
Cosmic pressure fronts mapped by Chandra
The collision of two giant clusters of galaxies has been imaged by NASA’s Chandra X-ray Observatory. For the first time, the pressure fronts in this system, which has been compared to a cosmic “weather system,” can be traced in detail. “We can compare this to an intergalactic cold front,” said Maxim Markevitch of the Harvard-Smithsonian…
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Science & Tech
Chandra finds “cool” black hole at heart of Andromeda Galaxy
A team of scientists from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., reported that the gas funneling into a supermassive black hole in the heart of the Andromeda Galaxy, designated as “M31,” is a “cool” million degrees Celsius. This unexpected result adds one more quirk to the strange behavior previously observed at the center…
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Science & Tech
Betelgeuse’s chromosphere beats like a human heart
For many years astronomers have known that the atmospheres of pulsating stars either expand or contract over time, but they have long puzzled over the question: “What physical mechanism drives these amazing dynamics?” Alex Lobel and Andrea Dupree of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge and Ronald Gilliland of the Space Telescope Institute…