Our Solar System is old. Our best estimates from radiometric dating of meteorites suggest the Sun and its planets (including Earth) were forming some 4.6 billion years ago. The Universe itself appears to be some 13.8 billion years old based on its observed rate of expansion and the properties of Read more
Looking up in to the night sky it’s not difficult to see why the ancient Greeks believed that all the stars in the night sky were fixed on a celestial sphere revolving around the Earth and other planets. From our view on Earth the stars appear to be at a Read more
Zeta Reticuli, a dim binary system of Sun-like stars only 39.5 light years away in the little constellation of Reticulum is strangely well-known. Why is it so famous? This system was once identified as the home of the little grey-faced and black-eyed humanoids who allegedly abducted Barney and Betty Hill Read more
A new image from the European southern Observatory’s Visible and Infrared Survey Telescope for Astronomy (VISTA) telescope reveals the glowing clouds of gas and filaments of dust surrounding hot young stars in the stellar nursery known as NGC 6357. Infrared observations like this can reveal features that cannot be seen Read more
Audiences flocked to see James Cameron’s epic movie Avatar, the story of a disabled human who gets a chance to live a new life as a 3m tall blue-skinned humanoid alien from a world called Pandora. In the movie Pandora is a lush jungle-covered moon of a gas giant planet Read more
Radio astronomy is the study of the radio frequencies emitted from stars, galaxies and other celestial objects. Radio waves are produced naturally from lightning and astronomical objects, or are produced by man-made communication techniques and broadcasting technology.Many radio telescopes are located around the globe and have helped discover new types Read more
Our galaxy, the Milky Way, is vaster than we puny humans can imagine.A huge (100 000 light years across) spiral of stars and nebulae embedded in the tenuous interstellar medium , the Milky Way is a about a thousand light years thick apart from where it swells into the great Read more
The hunt for planets located outside of our own Solar System is not a new concept.Since 1995 scientists and astronomers have been aware of these distant worlds orbiting their host stars.The first exoplanet discovered was 51 Pegasi located in the constellation of Pegasus.To date over 3000 potential exoplanets have been Read more
This image of the reflection nebula Messier 78 (NGC 2068) includes the soft glow of submillimetre-wavelength (infra red) radiation from clouds of interstellar dust grains running through the nebula.Dense clouds of gas and dust like this are the birthplaces of new stars. M78 is found in Orion, and appropriately Read more
A globular cluster is made of hundreds of thousands or even millions of stars packed together in a pretty compact ball. The stars in globular clusters are old and there’s never any sign of new stars forming in them. Older stars are usually yellow, orange and red, so those colours Read more
Today Sirius, the brightest star in the night sky is an unmistakable blue-white in colour although it does twinkle a lot and can appear to change colour. However no one would think of describing it as red.It is thus a source of confusion that many ancient writers describe the star Read more
![Star types from left to right: a red dwarf, our Sun, a blue dwarf, and R136a1 (hypergiant). Where star sizes are measured by radius, from centre to surface, and where 1 solar radius is equal to that of our Sun (km) - R136a1’s radius is 35.4 times greater than the Sun [approximately 24.8 million km]. Credit: Author: ESO/M. Kornmesser](https://armaghplanet.com/wp-content/uploads/2012/03/image-of-star-types.jpg)
How big is the largest known star? Compared to planets, stars will always be the overall group winners in terms of superior size. When you look at the night sky on a clear night and away from city lights, you will see that there are stars of varying sizes and Read more
Beautiful colour images of nebulae grace astronomy books and websites and have spread to mainstream culture. They are now familar to the public but what are these gaudy celestial spectacles? So what is a nebula? Nebula is latin for ‘cloud’ so it is the word astronomers use to call Read more
A new image of the Omega Nebula reveals amazing detail in a cosmic landscape of gas clouds, dust and newborn stars. Captured by the Very Large Telescope (VLT) at the European Southern Observatory, this is one of the sharpest views of this stellar birthplace ever taken from Earth’s surface. Read more
What was the Star of Bethlehem? Recorded only in the Gospel of Matthew, this mysterious celestial object is said to have heralded the Nativity. For millennia stargazers have wondered what it may have been. Now when Jesus was born in Bethlehem of Judea in the days of Herod Read more
A clear night sky is a thing of beauty and wonder. Thousands of scattered stars twinkle in the darkness. What are the stars? How do they live and die? Could an exploding star cause disaster on Earth? Over the past century or so astronomers have by observation and calculation established Read more
The debris from a vast cosmic explosion, the Crab Nebula in Taurus is a well-known spectacle. But what is it and how was it formed? On 4 July 1054 AD Yang Wei-T’e (?-?), astronomer to the Chinese emperor, carefully recorded a ‘guest star’ in the constellation of Taurus. Yang Read more
A team of astronomers based at the European Southern Observatory have announced the discovery of more than 50 new exoplanets orbiting nearby stars. This is the largest number of such new worlds ever announced at one time. One of these planets may enjoy conditions favorable for life on its surface. Read more
Once planets orbiting other stars were unknown as they could not be directly observed. Several decades ago one astronomer was certain he had found the planets of a nearby star and his work seemed so painstaking that the astronomical community accepted their existence. Today they are forgotten. Whatever happened to Read more
Once exoplanets, worlds orbiting other stars, were the stuff of science fiction but now we know of literally hundreds of real alien planets circling other stars. Astronomers can infer and sometimes measure the statistics and properties of exoplanets and some are extreme! Here are some record-breaking alien worlds. The Read more
Globular clusters, tightly packed masses of stars are dazzling celestial spectacles as shown by this new European Southern Observatory image. This dramatic image depicts Omega Centauri, one of 200 or so globular clusters orbiting our Milky Way galaxy. This is among the first images taken by the VLT Survey Telescope Read more
Lying more than 4000 light years from our Solar System, the Lagoon Nebula (M8) is a place where new stars are forming. Researchers at the multinational Gemini South telescope are uncovering its secrets. This dazzling portrait of a section of the Lagoon Nebula (M8) was captured by astronomers Julia Arias Read more
NGC 6302 is a beautiful example of a planetary nebula formed when a bloated red giant star transformed into a tiny white dwarf, belching about half its mass into space in the process. This dramatic image looks like some vast cosmic eruption, and that impression is entirely correct. We’re looking Read more
Gleaned from NASA and Hubblesite.org, here are some facts you may not know about the Hubble Space Telescope (HST). 1. The HST’s history is longer than you might have thought, going back to just after World War II. In 1946, the astronomer Lyman Spitzer (1914-97) identified the main advantages Read more
To observers on Earth, the great bull of Taurus has a fiery red eye. This is Aldebaran, an old red giant star which dwarfs our Sun. Let’s have a closer look at the facts and fiction about this aging star. If you go out after dark on a winter’s Read more
Kepler-11 is an amazing, newly-discovered system of exoplanets. About 2000 light years from Earth, six planets orbit a star like our Sun. Each planet is bigger and more massive than the Earth. This whole planetary system is squeezed into a region slightly larger than Mercury’s orbit. This bizarrely shrunken Read more
The giant star Betelgeuse will soon perish in a titanic explosion. Could this happen in the mythical “doomsday” year of 2012? Could dying Betelgeuse take us with it? “Beetlejuice! Beetlejuice! Beetlejuice!” was the chant which summoned the obnoxious ghost played by Michael Keaton in Tim Burton’s 1988 movie. Keaton’s character Read more
Don Pollacco, a research astronomer at Queens University Belfast, came to Armagh Planetarium to give a fascinating talk on exoplanets in January 2011. Afterwards Dr Pollaco kindly chatted to me about his experiences. CJ: Thanks for a really interesting talk. So why did you get into astronomy? DP: I was Read more
NASA’s amazing Kepler planet-searching spacecraft has made a significant new discovery. Planet Kepler-10b is an inhospitable world but it is one of the smallest confirmed exoplanets yet found and may be the most Earth-like world discovered so far. The Kepler satellite looks for planets passing between their parent star Read more
The smallest stars in the galaxy are the red dwarfs. Recent research suggests they are more common than previously suspected. Tiny, cool and dim compared to the Sun, they may seem unimportant. But consider this: red dwarfs not only outnumber every other type of star in the Universe but will Read more
The extra-solar planet HAT-P-1b has baffled astronomers since it was discovered in 2006. The planet is puffed up much larger than theory predicts. HAT-P-1 has a volume nearly twice than of Jupiter’s yet it contains only half Jupiter’s mass. Most exoplanets so far discovered fall into the category of Read more
Cepheid variables are massive, pulsating stars, valued by astronomers for the precise link between their brightness and steady pulsation. Let’s look at the history of Cepheid variables and how recent discoveries about these stars shatter established theories of stellar evolution. Cepheid variable stars have been known since the 18th Read more
Could HIP 13044 b be the strangest exoplanet yet found? We are getting used to the discoveries of bizarre exoplanets but newly-discovered world HIP 13044 b not only survived the cataclysm of its star swelling into a red giant, but it also originally came from another galaxy! If you Read more
Using the Hubble Space Telescope, astronomers have been looking ten thousand years into the future of the vast globular cluster Omega Centauri. Nearly 16 000 light years from Earth, Omega Centauri is a vast globular cluster of several million stars. Omega Centauri might be the core of a dwarf galaxy Read more
Gorgeous! Spectacular! Awesome! What else can I say about this stunning Turneresque image of the Lagoon Nebula (M8)? A typical stellar nursery, M8 lies about 4300 light years (1320 parsecs) from Earth in the constellation Sagittarius. About a hundred light years (31 parsecs) wide, it is actually several times as Read more
What is light? Here’s an easy introduction to the electromagnetic spectrum all the way from radio waves to gamma rays. Before the modern era of technological astronomy, to know anything about the Universe beyond our planet we relied on light. We had to see planets, stars, and so on, to Read more
It is difficult to look at this Hubble Space Telescope image of the nebula NGC 2467 without thinking about what it would be like to fly through it. It is easy to imagine floating through a beautiful softly glowing mist, something like the Mutara Nebula, scene of Kirk and Spock’s Read more
Imagine that once the Sun sets, rather than a dark sky sprinkled with a few thousand dim stars, we had a sky blazing with ten thousand or so stars blazing brighter than Venus. How different would astronomy, mythology, everyday life be? Planets orbiting stars in the NGC 3603 Young Cluster Read more
Here’s how rainbows are made. Some 13.7 billion years ago, a mere millionth of a second after the Big Bang, the first hydrogen and helium nuclei condensed out of a hot, dense soup of quarks and gluons. It took another 380 000 years or so for conditions in the ancient Read more
That amazing instrument, the Hubble Space Telescope (HST), has just celebrated its twentieth anniversary since it was placed in orbit. Since then, (after a rocky start, remember that dodgy mirror?) it has revolutionised not only what we know about cosmology, star formation, exoplanets and so on, but also how we Read more
At first glance Gliese 710 is not a very distinguished star. A K7 class orange dwarf a bit more than half as massive as the Sun, it currently lies about 63 light years from us in the constellation Serpens. It is moving fast though and that is why one reason Read more
Around this time of year, go outside after 9pm on a clear night and look at the sky. Even if it is not quite dark a bright star will be visible in the south. This is Vega, the third brightest star in our sky (only Sirius and Arcturus are brighter). Read more
About 490 light years from our planet in the constellation of Monoceros lies a G type star designated COROT-7. A little smaller and dimmer than our Sun, this star is circled by at least two planets, one of which, COROT-7b, is the most similar exoplanet to Earth yet discovered. Read more
Some 150 light years from Earth in the constellation of Pegasus lies the star HD 209458 and its planetary system. The star is almost a clone of our own Sun, but one its planets is completely unlike anything in our Solar System. The exoplanet HD 209458b has a mass more Read more