51 Pegasi b, about 50 light-years from Earth in the constellation of Pegasus, was discovered in 1995 and was the the first confirmed exoplanet to be found orbiting an ordinary star like our Sun. It is the archetypal Hot Jupiter -- a class of planets similar in size and mass to Jupiter but orbiting much closer to their parent stars.

Since that landmark discovery, more than 1,900 exoplanets in 1,200 planetary systems have been confirmed, but 51 Pegasi b now has another "first" - it has been directly detected in visible light.

Astronomers have found evidence of a giant void that could be the largest known structure in the universe. The “supervoid” solves a controversial cosmic puzzle: it explains the origin of a large and anomalously cold region of the sky. However, future observations are needed to confirm the discovery and determine whether the void is unique.

In 2004, astronomers examining a map of the radiation leftover from the Big Bang (the cosmic microwave background, or CMB) discovered the Cold Spot, a larger-than-expected unusually cold area of the sky. The physics surrounding the Big Bang theory predicts warmer and cooler spots of various sizes in the infant universe, but a spot this large and this cold was unexpected.

Now, a team of astronomers led by Dr. Istvan Szapudi of the Institute for Astronomy at the University of Hawaii at Manoa may have found an explanation for the existence of the Cold Spot, which Szapudi says may be "the largest individual structure ever identified by humanity."

Astronomers and planetary scientists have been waiting with bated breath for the first detailed close-up images of Ceres, the solar system’s largest asteroid. Now, with NASA’s Dawn spacecraft approaching closer each day, tantalizing new color imagery has revealed new details of the geological processes that formed Ceres.

New Horizons will soon reach Pluto, and is expected to find new moons and possibly a ring system. Could it find a moon of a moon? Or a moon with rings?

As we search for an answer, we will find out about why our Moon finds it hard keep a satellite at all, even just for a few years, and why an early satellite released by Apollo 16 unexpectedly crashed into the Moon. Also we'll chase up an intriguing puzzle about Saturn's moon Rhea.

Let's start with our own Earth / Moon system. Why is the Moon's orbit stable - and why can't our Moon have moonlets, or can it?

A team of astronomers studied the simultaneous collision of four galaxies in the galaxy cluster Abell 3827 and could trace out where the mass lies within the system and compare the distribution of the dark matter with the positions of the luminous galaxies.

Although dark matter cannot be seen, the team could deduce its location using a technique called gravitational lensing. The collision happened to take place directly in front of a much more distant, unrelated source. The mass of dark matter around the colliding galaxies severely distorted spacetime, deviating the path of light rays coming from the distant background galaxy -- and distorting its image into characteristic arc shapes.

It is galaxy season in the northern hemisphere, with Ursa Mayor at the zenith during the night and the Virgo cluster as high as it gets. And if you have ever put your eye on the eyepiece of a large telescope aimed at a far galaxy, you will agree it is quite an experience: you get to see light that traveled for tens or even hundreds of millions of years before reaching your pupil, crossing sizable portions of the universe to make a quite improbable rendez-vous with your photoreceptors. 

Titan, Saturn's largest moon, is one of the most Earthlike places in the solar system. 

It has a thick, hazy atmosphere and surface rivers, mountains, lakes and dunes, which is why the Cassini-Huygens is studying it. But sometimes new data bring new mysteries, such as the seemingly wind-created sand dunes spotted by Cassini near the moon's equator, and the contrary winds just above.
Not all exoplanets are going to be habitable, many will be just the opposite. Astronomers have measured the temperature of the atmosphere of an exoplanet with unequaled precision and determined we won't be vacationing there any time soon. By crossing two approaches, using the HARPS spectrometer and a new way of interpreting sodium lines, researchers have been able to conclude that exoplanet HD 189733b is showing infernal atmospheric conditions, with wind speeds of more than 1,000 kilometers per hour and a temperature 3,000 degrees. 
How fast the universe has been expanding since the Big Bang is something of a puzzling question. It wasn't that long enough that we didn't know it was accelerating at all, and a new study finds the acceleration of the expansion of the universe might not be as fast as thought.

The currently accepted view of the universe expanding at a faster and faster rate, pulled apart by an unknown force labeled under the umbrella term 'dark energy', is based on observations that resulted in the 2011 Nobel Prize for Physics. But observations based on uniform type Ia supernovae - cosmic "beacons" - may actually fall into different populations.

That's like comparing 100-watt light bulbs only to find out they vary in brightness.