Winter is over, and the famous winter season constellations that come with it have all but disappeared from our night skies. Summer is coming, and with it comes a different observing window to the cosmos. As it has been doing for the past 4.6 billion years, planet Earth continues to revolve around our parent star, oblivious to a species of intelligent beings gazing up from its plains to the heavens full of splendour above. With its movement around the sun, our planet inadvertently provides a slightly different perspective onto the universe every day.
For us members of this intelligent species on this tiny rocky planet, the summer months bring into view a splendour like no other. Sprawled across the sky in breathtaking fashion is a faint mist of white light, home to 400 billion stars and uncounted cosmic wonders. Behold, the galactic plane of the Milky Way ‒ our star’s repose in the vast emptiness of space.
A galaxy is, in simple terms, a massive collection of gas and dust in one, albeit large, region in space, which gives rise to incredulous numbers of stars and planets. A higher concentration of this material is found towards the centre of the galaxy, and therefore, a higher concentration of stars is also located in this area. Hence, the centre of the galaxy is brighter than its outer regions. In the summer months, the planet’s night side faces the centre of the galaxy, revealing all those cosmic objects located closer to our own galaxy’s centre than us.
From our tiny island in the Mediterranean Sea, the Milky Way core can be observed by looking towards the south. In the westernmost part of the famous constellation of Sagittarius, also referred to as the Teapot, the centre of the galaxy itself can be found. However, the galactic plane itself hosts hundreds of incredible formations that have taught us much of what we know and understand about how the universe works.
The Lagoon nebula, also found in the constellation of Sagittarius, is one of the brightest emission nebulae visible from Earth, easily visible with binoculars. Located about 4,000 light years from Earth, the nebula is one of the closest places to our home planet with active star formation. Close by, also in Sagittarius, the Trifid nebula, home to a cluster of some 3,000 young stars can be found.
In the Ophiuchus constellation, the Rho Ophiuchi cloud complex, covering about 4.5 by 6.5 degrees of sky, can be found. This cloud complex, also a star forming region, is classified as a dark nebula, with a large amount of dust present, resulting in a filamentous appearance. The cloud complex is also home to the first brown dwarf – a failed star – ever identified.
Stretching from Lyra to Centaurus, the brighter regions of the Milky Way offer a myriad of such objects in their midst. No telescope is necessarily required either, although a telescope with appropriate knowledge of how to use it is a great asset. Just a pair of binoculars may satisfy the expectations of many, being enough to make out many of the brightest parts of the galactic plane. Just viewing the summer night sky from a sufficiently dark location is already enough to make out some of the large scale structure of our home galaxy.
Josef Borg is a PhD student at the University of Malta’s Institute of Space Sciences and Astronomy, and president of the Astronomical Society of Malta.
Did you know?
• The Milky Way core is 26,000 light years away. Our sun orbits the Milky Way centre, along with the rest of the solar system, in an orbit with a diameter 52,000 light years wide. The sun takes around 225 to 250 million years to complete one orbit around the Milky Way, travelling at a speed of around 230km every second.
• At the centre of the Milky Way, a supermassive black hole holds it all together. What is at the Milky Way’s core? The answer: one of the strangest objects in the cosmos – a supermassive black hole. Weighing in at over four million times the mass of the sun, Sagittarius A* is the object around which all of the objects in the Milky Way orbit, and its gravitational effects contribute immensely in keeping the entire galaxy in its current state.
• We are in the relatively outer reaches of our own galaxy. At a distance of 26,000 light years from the core, our solar system is about half the span of the galaxy out from the centre (the galaxy is about 100,000 light years across). Our solar system is in one of the minor arms of the Milky Way’s spiral structure.
For more trivia see: www.um.edu.mt/think
• Apollo-era data reveal moon’s tectonic activity
When the Apollo astronauts deployed seismometers, they revealed that the moon quivers and shakes in many ways. Between 1969 and 1977, these instruments picked up all kinds of vibrations, most of which were linked to meteor strikes, tidal forces and thermal changes. But there were also 28 shallow, but surprisingly powerful quakes of unknown origin.
• Solar system ‘twin’ is missing its baby Jupiters
LkCa 15, a young sun-like star, has excited astronomers ever since early research seemed to reveal evidence of perhaps several planets forming in the disk of gas and dust around the star. LkCa 15 is about as old as our sun when Jupiter and Saturn took shape, so the findings promised fresh insights into solar system formation. However, recent observations with the Subaru Telescope in Hawaii have generated sharper images than ever before, throwing these previous discoveries into question.
For more science news, listen to Radio Mocha on Radju Malta and www.fb.com/RadioMochaMalta
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