What powers the most luminous galaxies?

Galaxy-galaxy interactions have long been known to influence galaxy evolution. They are commonplace events, and a large majority of galaxies show signs of interactions, including tidal tails or other morphological distortions. ...

Habitable water world exoplanets

There are currently about fifty known exoplanets whose diameters range from Mars-sized to several times the Earth's and which also reside within their stars' habitable zone – the orbital distance within which their surface ...

Planetary nebula lasers

Astronomical masers (the radio wavelength analogs of lasers) were first identified in space over fifty years ago and have since been seen in many locations; astronomical lasers have since been seen as well. Some of the most ...

Unconfirmed near-Earth objects

Near-Earth objects (NEOs) are small solar system bodies whose orbits sometimes bring them close to the Earth, potentially threatening a collision. NEOs are tracers of the composition, dynamics and environmental conditions ...

Outflowing gas from galaxy supermassive black hole nuclei

Supermassive black holes at the nuclei of most galaxies, including our Milky Way, develop gradually as material accretes onto the seed black hole. The physical processes that drive this growth – the so-called feeding and ...

Does some dark matter carry an electric charge?

Astronomers have proposed a new model for the invisible material that makes up most of the matter in the Universe. They have studied whether a fraction of dark matter particles may have a tiny electrical charge.

Finding galaxies with active nuclei

The nuclei of most galaxies host supermassive black holes with millions or even billions of solar-masses of material. Material in the vicinity of such black holes can accrete onto a torus of dust and gas around the black ...

Is dark matter made of primordial black holes?

Astronomers studying the motions of galaxies and the character of the cosmic microwave background radiation came to realize in the last century that most of the matter in the universe was not visible. About 84 percent of ...

The gamma ray burst – supernova connection

A "core-collapse" supernova occurs when the iron core of a massive star collapses under the force of gravity and then rebounds, generating pressure waves and shocks that propagate outward. A superluminous supernovae is a ...

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