Small dust particles in a disk of gas around a young star, according to current models, gradually coagulate during the first million years until kilometer-sized objects are formed. These ...

Cambridge, MA An exploding star known as a Type Ia supernova plays a key role in our understanding of the universe. Studies of Type Ia supernovae led to the discovery of dark energy, whi...

Moon's craters, together with samples of the surface returned during the Apollo program, tell the story of impacts from two different populations of small bodies. The first rocky collect...

Quasars are among the most energetic objects in the universe, with some of them as luminous as ten thousand Milky Way galaxies. Quasars are thought to have massive black holes at their c...

This movie of the March 6, 2012 X5.4 solar flare was captured by the Atmospheric Imaging Assembly instrument aboard NASA’s Solar Dynamics Observatory in the 171 Angstrom wavelength. The S...

Daniel Eisenstein is investigating the universe, using galaxies as his ruler, seeking to understand the cosmos' large-scale structure and confirm theories about the dark energy that drive...

A "super-Earth" is an exoplanet (a planet around another star) whose mass is between about two and ten Earth-masses. Planets larger than this are closer to Uranus and Neptune in size (an...

An ultra-luminous X-ray source (ULX) emits more radiation in the X-rays than do a million suns at all wavelengths. ULXs are rare: Most galaxies, including our own Milky Way, have none, a...

Cambridge, MA Our solar system contains three types of planets: rocky, terrestrial worlds (Mercury, Venus, Earth, and Mars), gas giants (Jupiter and Saturn), and ice giants (Uranus and N...

The formation and development of the solar system, long a topic of study for philosophers and scientists, is today often used as a case study for the formation and development of planetar...