In nabbing exoplanets that are precariously close to their stars, astronomers have discovered a shortage of one type of alien world. It's a predicted class of Neptune-sized world that orbits just a few million miles from its star, much closer than the 93-million-mile distance between Earth and the Sun. Dubbed "hot Neptunes," these planets would have atmospheres that are heated to more than 1,700 degrees Fahrenheit (hot enough to melt silver).

However, the mysterious hot-Neptune deficiency suggests that these planets are rare, or, they were plentiful at one time, but have since disappeared. In... Read more

November 16 marks the premiere of a unique film and musical experience inspired by the Hubble Space Telescope’s famous Deep Field image. It represents a first-of-its-kind collaboration between Grammy award-winning American composer and conductor Eric Whitacre, producers Music Productions, multi award-winning artists 59 Productions, and the Space Telescope Science Institute (STScI). Deep Field: The Impossible Magnitude of our Universe features a variety of Hubble’s stunning imagery and includes 11 computer-generated visualizations of far-flung galaxies, nebulas, and star clusters developed by... Read more

The explosive end to a massive star's life is one of the most powerful blasts in the universe. The material expelled by the violent stellar death enriches our galaxy with heavier elements, the building blocks of new stars and even planetary systems. Astronomers have diligently searched for the doomed progenitor stars in pre-explosion images. Studying these stars could help them in their quest to better understand stellar evolution.

Their quest has turned up a few pre-supernova stars. But the doomed stars for one class of supernova have eluded discovery: the hefty stars that explode as Type Ic... Read more

Like a fly that wanders into a flashlight’s beam, a young star’s planet-forming disk is casting a giant shadow, nicknamed the “Bat Shadow.” Hubble’s near-infrared vision captured the shadow of the disk of this fledgling star, which resides nearly 1,300 light-years away in a stellar nursery called the Serpens Nebula. In this Hubble image, the shadow spans approximately 200 times the length of our solar system. It is visible in the upper right portion of the picture. The young star and its disk likely resemble what the solar system looked like when it was only 1 or 2 million years old.

The term "HAZMAT" connotes danger. In this case, it's on a cosmic scale, where violent flares of seething gas from small, young stars may make entire planets uninhabitable. NASA's Hubble Space Telescope is observing such stars through a large program called HAZMAT — HAbitable Zones and M dwarf Activity across Time. This is an ultraviolet survey of red dwarfs — referred to as "M dwarfs" in astronomical circles — at three different ages: young, intermediate, and old.

Approximately three-quarters of the stars in our galaxy are red dwarfs. Most of the galaxy's "habitable-zone" planets orbit these... Read more

Our solar system has eight major planets, and nearly 200 moons. Though astronomers have to date found nearly 4,000 planets orbiting other stars, no moons have yet been found. That hasn't been for any lack of looking, it’s just that moons are smaller than planets and therefore harder to detect.

The Hubble and Kepler space telescopes found evidence for what could be a giant moon accompanying a gas-giant planet that orbits the star Kepler-1625, located 8,000 light-years away in the constellation Cygnus. The moon may be as big as Neptune and it orbits a planet several times more massive than... Read more

Imagine crushing more than 50,000 aircraft carriers into the size of a baseball. This describes neutron stars. They are among the strangest objects in the universe. Neutron stars are a case of extreme physics produced by the unforgiving force of gravity. The entire core of an exploded star has been squeezed into a solid ball of neutrons with the density of an atom’s nucleus. Neutron stars spin as fast as a blender on puree. Some spit out death-star beams of intense radiation — like interstellar lighthouses. These are called pulsars.

These beams are normally seen in X-rays, gamma-rays, and radio... Read more

The universe is so huge that it's estimated that a star explodes as a supernova once every second. Astronomers capture a small fraction of these detonations because they are comparatively short-lived, like fireflies flickering on a summer evening. After skyrocketing to a sudden peak in brightness, a supernova can take weeks to slowly fade away.

For the past decade astronomers have been befuddled by a more curious "flash-in-the-pan" that pops up and then disappears in just a few days, not weeks. It's called a Fast-Evolving Luminous Transient (FELT). Only a few FELTs have been seen in telescopic sky... Read more

When Galileo discovered Jupiter's moon Europa in 1610, along with three other satellites whirling around the giant planet, he could have barely imagined it was such a world of wonder.

This revelation didn't happen until 1979, when NASA's Voyager 1 and 2 flew by Jupiter and found evidence that Europa's interior, encapsulated under a crust of ice, has been kept warm over billions of years. The warmer temperature is due to gravitational tidal forces that flex the moon's interior — like squeezing a rubber ball — keeping it warm. At the time, one mission scientist even speculated that the Voyagers... Read more

In the 1400s, two power struggles were taking place quadrillions of miles apart. In England, two rival branches of the royal House of Plantagenet were battling each other for control of the country's throne. And, in a nebula far, far away, a cluster of stars was waging a real-life star wars, with the stellar members battling each other for supremacy in the Orion Nebula. The gravitational tussle ended with the system breaking apart and at least three stars being ejected in different directions.

Astronomers spotted two of the speedy, wayward stars over the past few decades. They traced both stars... Read more