Researchers have used the Chandra X-Ray Observatory to understand just how large supermassive black holes can get by performing a very detailed census of the mysterious objects. These are the gigantic black holes, with millions of times the mass of our Sun, that sit at the centre of almost every galaxy. The largest of them reach 100 million solar masses and gained this weight early - then they ran out of material to consume. The smaller holes, between 10 and 100 million solar masses, have been more frugal with the gas and dust they consume, and continue to grow to this day.

From the big to the small, physicists want to know it all. But what good is this knowledge unless you can bring it together and make something of it? Michael Mallary in his book Our Improbable Universe connects quarks to the likelihood of a deity and makes a lot of it. Sometimes rambling but always pertinent, his musings on subjects as diverse as multi-universes and the good fortune of having fissile material in the Earth's mantle makes for a very interesting and thought provoking read.

Scientists working with the Mars Exploration Rover Spirit believe it's discovered another rock that was affected by liquid water in the past. Dubbed "Peace", the rock contains more sulfate salt than any other rock Spirit has examined so far. Normally this sulfur is at the surface of the rock, but Peace has this material deep inside too. The scientists have two theories for how these sulfates formed, but both involve large amounts of liquid water.

The European Space Agency's Mars Express spacecraft took this image of the central region of the Valles Marineris. This 4,000 km (2,500 mile) long gash in the surface of Mars was probably created when the relatively nearby Tharsis bulge rose up from volcanic activity to a height of more than 10 km (6 miles). A similar situation exists here on Earth (on a smaller scale), at the Kenya rift in east Africa.

Now who put that "Valentine" up there in the stars? Although the splendid IC 1805 will be lost to this week's Moon, there will be no shortage of things to view as we explore selenography with dorsa, mountains, impact craters and "hidden" surprises! With plenty of history as well as lunar features to tantalize all observers, we'll begin the week with a day of "love", and learn to love the Moon and all its amazing details by week's end. So get out your telescopes...

Because here's what's up!

There should be relatively safe orbits within the swirling gas and dust of a newly forming solar system that could allow planets to gain mass without being destroyed. This is according to a new simulation developed by astronomers from the University of Indiana. They built a simulation that showed how gravitational instabilities form which can bring planets together quickly. New theories of planetary formation predict that large gaseous planets, like Jupiter and Saturn, need to hurry up and form before their material is blown away by the growing star.

Astronomers from Carnegie and Caltech have pinpointed the exact location of the first gamma-ray burst detected by NASA's Swift observatory on December 23, 2004. The team used the telescopes at Las Campanas Observatory in Chile to watch the fading afterglow of the explosion in the constellation of Puppis. Three more bursts were detected in January, and they have also been studied by various telescopes around the world. Researchers are hoping they can use these intense explosions as a kind of flashlight, to illuminate distant objects which are normally too dark to study.

The massive Ariane 5-ECA finally lifted off on Saturday, carrying two satellites into orbit, and demonstrating that the launcher is ready for business. The rocket blasted off from Europe's spaceport in French Guiana at 2103 GMT (4:03 pm EST), and deployed its payloads about 90 minutes later. The primary payload was the Spanish XTAR-EUR military communications satellite, but it was also carrying Sloshsat, a satellite designed to measure how liquids behave in microgravity. The Ariane 5-ECA can carry up to 10 tonnes to geostationary transfer orbit.

Amateur photographer John Chumack took this picture of Spiral Galaxy NGC-253, which is located in the constellation of Sculptor. The telescope was a Takahashi Epsilon 250mm and ST8XE CCD camera, on a Software Bisque Paramount ME, taken on Mount Joy, New Mexico, New Mexico Skies Resort. John operated the telescope remotely from Dayton, Ohio using Arnie Rosner's Rent-A-Scope setup. John has been imaging the sky for 2 decades, and has an amazing collection of pictures at his website: Galactic Images. If you're an amateur astrophotographer, visit the Universe Today forum and post your pictures, we might feature it in the newsletter.

By tracing back the family tree of cyanobacteria, a researcher from Washington University in St. Louis believes these tiny organisms began life in fresh water, not salt water as most biologists theorized. Cyanobacteria use light, water and carbon dioxide to produce oxygen and biomass, and they probably got their start 2 billion years ago in fresh water, and then evolved to survive in saltier environments.

The massive Ariane 5-ECA rocket is ready for its second flight this weekend, after its first attempt ended in destruction back in 2002. The 50m (160 ft) tall rocket is capable of carrying more than 10-tonnes into geostationary orbit. On this second test flight, the ECA is equipped with two satellites: the Spanish XTAR-EUR military communications satellite and SloshSat, which will see how fluids work in orbit. If everything goes well, the ECA should lift off from the Kourou spaceport in French Guiana on Saturday.

Researchers from the Georgia Institute of Technology have uncovered a surprising link between air pollution levels over land, and the growth of phytoplankton in the ocean. These tiny, but hardworking, aquatic plants carry out half the Earth's photosynthesis, and are responsible for removing tremendous quantities of carbon dioxide from the atmosphere. Normal dust storms produce iron which the phytoplankton can't use, but when it's modified by sulfur dioxide pollution, the iron becomes soluble and can trigger phytoplankton growth.

The inner planets in our solar system are largely made of rock, which are formed from silicon. But in a different solar system, with a different distribution of minerals, planets could be mostly formed from carbon instead. Inside these planets, where the heat and pressure are intense, this carbon would form layers of diamonds. Small versions of these planets fall to Earth all the time, in the form of carbonaceous chondrite meteorites, which contain different carbon compounds, such as carbides, organics and occasionally even diamonds.

Astronomers have known for a few years now that there's a direct connection between the size of a galaxy and the supermassive black hole that lurks at its centre. Until recently, they haven't been sure why this relationship exists. A new computer simulation from the Max Planck Institute has shown that growing black holes release a blast of powerful energy that actually regulates the amount of star formation in the galaxy. The bigger the galaxy, the longer this takes to happen, so the black hole can become larger.

This photograph of Mimas, one of Saturn's moons, shows a head-on view of its largest crater Herschel - making it look like the Death Star from the Star Wars series of movies. Mimas is only 398 kilometers (247 miles), so the impact that formed this crater probably nearly destroyed the moon. Herschel is 130 kilometers wide (80 miles), and has a tall central peak similar to many craters on our own Moon. Cassini took this image on January 16, 2005 at a distance of only 213,000 kilometers (132,000 miles).

Born February 15, 1564, Galileo Galilee was a scientist, philosopher, mathematician, professor, optician, musician, painter, and father of three. Despite all these accomplishments, it is easy to conceive that - like many amateur astronomers of today - one of his greatest loves was to turn eye and telescope upon the wonders of the night sky. In this article by Astro.Geekjoy's Jeff Barbour we retrace a few of his steps and come to a deeper insight into the kinds of questions driving his personal quest for understanding.

Radio telescopes around the world listened for signals from Huygens to measure wind speeds on Titan as the probe descended through its atmosphere last month. The telescopes discovered that winds on Titan are very weak near the surface, and then increase in intensity with altitude. Huygens passed through winds going nearly 435 kph (270 mph) at an altitude of 120 km (75 miles). Cassini was originally supposed to make these measurements, but there was a configuration problem with one of its receivers.

NASA has released new colour images of Saturn's northern hemispheres taken by Cassini - and the Ringed Planet is looking a little blue. This blue colour of Saturn's atmosphere is probably linked to the cloud-free nature of the upper atmosphere, but imaging scientists still aren't really sure. Icy moon Mimas is set against the image, and a few large craters are visible on its surface. This image was taken on January 18, 2005, when the spacecraft was approximately 1.4 million kilometers (870,000 miles) from Saturn.

NASA's Spitzer Space Telescope has found the dusty disc of planetary material surrounding an extremely low-mass brown dwarf. The failed star, called OTS 44, is only 15 times the mass of Jupiter, and is located 500 light-years away in the Chamaeleon constellation. Previously, the smallest brown dwarf known to have such a disc was twice as massive. Astronomers are now wondering if a habitable world could form around such a small, dim dwarf.

Astronomers from Penn State and Caltech have found the smallest extrasolar planet yet, orbiting a pulsar 1,500 light-years away. The small planet - the fourth discovered around this pulsar - has 1/5th the mass of Pluto, and orbits approximately the same distance as the asteroid belt orbits the Sun. The pulsar is spinning quickly, and gives off pulses of radiation at a very regular rate. Fluctuations in the pulses can then be used to calculate the orbits of planets going around them down to the size of large asteroids.