Nighttime Titanium Oxide Snow Leaves Dayside Cloud-Free and Cooler

Travelers to the nightside of exoplanet Kepler-13Ab should pack an umbrella because they will be pelted with precipitation. But it's not the kind of watery precipitation that falls on Earth. On this alien world, the precipitation is in the form of sunscreen.

Ironically, the sunscreen (titanium oxide) is not needed on this side of the planet because it never receives any sunlight. But bottling up some sunlight protection is a good idea if travelers plan on visiting the sizzling hot, permanent dayside, which... Read more

Neutron Star Collision Cooks Up Exotic Elements, Gravitational Waves

When some people get in the kitchen, they create a delicious meal but leave behind a chaotic mess of splattered food and dirty dishes. Cosmic cookery can be just as messy. While a star can create chemical elements as heavy as iron within its core, anything heavier needs a more powerful source like a stellar explosion or the collision of two neutron stars.

Colliding neutron stars can yield gold, plutonium, and a variety of other elements. Theoretically, they also generate gravitational waves as they spiral... Read more

The Comet that Came in from the Cold

A solitary frozen traveler has been journeying for millions of years toward the heart of our planetary system. The wayward vagabond, a city-sized snowball of ice and dust called a comet, was gravitationally kicked out of the Oort Cloud, its frigid home at the outskirts of the solar system. This region is a vast comet storehouse, composed of icy leftover building blocks from the construction of the planets 4.6 billion years ago.

The comet is so small, faint, and far away that it eluded detection. Finally, in May 2017, astronomers using the... Read more

An Asteroid That Split in Two 5,000 Years Ago Is Spouting a Comet Tail

Astronomers categorize the minor bodies in the solar system according to their location and physical composition. Comets are a loose collection of ice and dust that fall in toward the Sun from beyond the orbits of the major planets, and grow long tails of dust and gas along the way. Asteroids are rocky or metallic and are relegated to a zone between Mars and Jupiter. But nature isn't that tidy. The Hubble Space Telescope photographed a pair of asteroids orbiting each other that have a tail of dust, which is... Read more

Alien world traps most of the visible light falling into its atmosphere

Don't go looking for the proverbial black cat eating licorice in a coal bin on the planet WASP-12b. Twice the size of any planet found in our solar system, the world is as black as fresh asphalt. Unlike other planets in its class, WASP-12b has the unique capability to trap at least 94 percent of the visible starlight falling into its atmosphere.

The temperature of the atmosphere is a seething 4,600 degrees Fahrenheit, which prevents the formation of reflective clouds on the day side. The planet orbits so... Read more

Scorching "Hot Jupiter" Has a Stratospheric Layer

Only when we fly in a commercial jet at an altitude of about 33,000 feet do we enter Earth's stratosphere, a cloudless layer of our atmosphere that blocks ultraviolet light. Astronomers were fascinated to find evidence for a stratosphere on a planet orbiting another star. As on Earth, the planet's stratosphere is a layer where temperatures increase with higher altitudes, rather than decrease. However, the planet (WASP-121b) is anything but Earth-like. The Jupiter-sized planet is so close to its parent star that the top of the... Read more

The Tiny Moon Phobos Is Photographed During Its Quick Trip Around Mars

While photographing Mars, NASA’s Hubble Space Telescope captured a cameo appearance of the tiny moon Phobos on its trek around the Red Planet. Discovered in 1877, the diminutive, potato-shaped moon is so small that it appears star-like in the Hubble pictures. Phobos orbits Mars in just 7 hours and 39 minutes, which is faster than Mars rotates. The moon’s orbit is very slowly shrinking, meaning it will eventually shatter under Mars’ gravitational pull, or crash into the planet. Hubble took 13 separate exposures... Read more

Gravitational lens helps reveal "fireworks" in the early universe

When the universe was young, stars formed at a much higher rate than they do today. By peering across billions of light-years of space, Hubble can study this early era. But at such distances, galaxies shrink to smudges that hide key details. Astronomers have teased out those details in one distant galaxy by combining Hubble’s sharp vision with the natural magnifying power of a gravitational lens. The result is an image 10 times better than what Hubble could achieve on its own, showing dense clusters of brilliant, young stars that resemble cosmic fireworks.

Young, Dead, Compact, Disk Galaxy Surprises Astronomers, Offers New Clues to How Modern-Day Elliptical Galaxies Formed

Astronomers combined the power of a “natural lens” in space with the capability of NASA’s Hubble Space Telescope to make a surprising discovery—the first example of a compact yet massive, fast-spinning, disk-shaped galaxy that stopped making stars only a few billion years after the big bang. Researchers say that finding such a galaxy so early in the history of the universe challenges the current understanding of how massive galaxies form and evolve. Astronomers... Read more

Webb Telescope Guaranteed Time Observations Targets Announced

Mission officials for NASA’s James Webb Space Telescope announced some of the science targets the telescope will observe following its launch and commissioning. These specific observations are part of a program of Guaranteed Time Observations (GTO), which provides dedicated time to the scientists that helped design and build the telescope’s four instruments. The broad spectrum of initial GTO observations will address all of the science areas Webb is designed to explore, from first light and the assembly of galaxies to... Read more