Sir Thomas Brisbane Planetarium

Our next feature is ‘X’ for ‘X-ray Astronomy’. ✨

When you open your eyes to your surroundings, light enters and reaches the retina, which detects light and dark, as well as colour. Your vision is limited though, with most people only able to detect red, green, and blue light, giving them a sense of the colour spectrum, from red to violet. The mix of those colours is what we call white light, and to scientists, it’s the visible spectrum. Your skin, however, can detect ultraviolet, and if it receives too much, you become sunburned. Then there’s infrared, which we feel as heat.

Light is part of the electromagnetic spectrum, which extends from gamma rays to radio waves, and by using different detectors, we can sample each part of the spectrum. Our atmosphere blocks gamma rays, x-rays, and the shorter wavelengths of ultraviolet, but allows visible light and some radio waves to pass through, and in 1932, the first detection of radio waves from space was made, by accident.

In 1948, the first observation of x-rays from the Sun was made, using captured and repurposed German V2 rockets to get above most of the atmosphere, and from the 1960s, satellite observations made it possible to do more widespread investigation of x-ray sources in deep space.

When most of us think of x-rays, we probably think of medical examinations, like looking at broken bones. Astronomers, however, study x-ray sources because the observations provide clues to very energetic processes, such as in very hot environments, or energetic particles being accelerated in a strong magnetic field around a pulsar, as in the Crab Nebula.

Discover more about our galaxy at the Sir Thomas Brisbane Planetarium: https://bnecouncil.cc/4sOcwCY



📸: NASA - National Aeronautics and Space Administration

Step into the stars at The Sir Thomas Brisbane Planetarium! Inside our fully immersive Cosmic Skydome you’ll experience space like never before, from breathtaking galaxies to unforgettable journeys through the universe.

🗓️ 16 Jun, Cosmic Collisions
🗓️ 20 Jun, The Dark Side of the Moon
🗓️ 21 Jun, Journey to the Stars

Book now to secure your spot under the stars: https://bnecouncil.cc/4ovl4yf

Our next feature is ‘W’ for ‘White Dwarf’. ✨

Stars come in a range of sizes and masses, from feeble red dwarfs to red supergiants. The smallest stars can be thousands of times fainter than the Sun, and about half the size of Saturn. While the largest supergiants can be millions of times brighter than the Sun, and over 1,000 times larger.

A white dwarf is a star that has stopped producing energy through nuclear fusion. Its own gravity has shrunk it to a very dense, compact object similar in size to Earth, and its active life is over. Then it begins the slow process of cooling down to a black dwarf. While the Universe isn’t yet old enough to have produced any black dwarfs, that’s what a white dwarf will become. Think of it like the glowing embers of a campfire, still hot but slowly fading away.

White dwarfs may have originally been as much as ten times the Sun’s mass, but the average one is only about half the Sun’s mass. However, there is a limit to a white dwarf's mass at about 1.44 times the Sun’s mass. If a white dwarf is orbiting another star, and that star becomes a red giant, it can expand enough for the white dwarf to pull material from it on to itself. When the extra material increases the mass of the white dwarf to more than 1.44 times that of the Sun, the still-hot dwarf can restart nuclear fusion, followed by a runaway fusion reaction that can destroy the dwarf in a Type 1a supernova event.

The nearest white dwarf to Earth is a companion to Sirius, the brightest night-time star. It can be hard to see due to the huge difference in brightness, as it’s about 10,000 times fainter than Sirius, and known as Sirius B. As for the Sun, it will swell and become a red giant over the next 5 billion years or so, perhaps becoming as large as Earth’s orbit. Then, after casting off its outer layers, it will become a white dwarf and start the long fade to darkness.

⭐ Fun fact! A cubic centimetre of white dwarf material would weigh between 10 kilograms and 10 tonnes.



📸: NASA - National Aeronautics and Space Administration

The darker the sky, the brighter the stars! Stare up at our night sky this month and discover our Astro Highlights:

🌑 9 and 10 June: Look into the night sky and see Jupiter and Venus pass close together,
🌙 17 and 18 June: Our planets and Moon are coming together, with Mercury, Jupiter and Venus grouped with crescent Moon.

Find out more about our night skies from our experts at the Sir Thomas Brisbane Planetarium: https://bnecouncil.cc/4sR5uNZ

📸: NASA - National Aeronautics and Space Administration

🪐 Now's the time to be keeping an eye on the western evening sky, with Jupiter apparently drawing closer to Venus over the next few weeks; they are now the brightest two objects in that part of the sky. The word 'planet' comes from the Greek 'planetes', meaning wanderers, and you can see them wandering from night to night during evening twilight. Jupiter and Venus will appear closest on 9-10 June, and Mercury will come up from below to make a trio towards mid-June, though it will be much less bright than the other two.

Our next feature is ‘V’ for ‘Venus’. ✨

Named after the Roman goddess of love and beauty, equivalent to the Greek Aphrodite. It was thought in ancient times to be two separate objects, known as the morning star and the evening star, terms that are still occasionally used today by the public. While stars make their own light, Venus shines by reflecting the sunlight, and is often referred to as Earth’s sister planet.

Venus is spectacularly bright, because it receives nearly twice the level of sunlight we do, and its clouds reflect around 75% of the light back into space. As a result, Venus may be the first object to appear in evening twilight (apart from the Moon), and the last to disappear in the morning light. When Venus is well away from the Sun and if you know where to look, this planet can be spotted in daylight!

Through a telescope, Venus shows no detail and is just uniform white cloud. Although, observation in ultraviolet does show structure in the clouds. Below the clouds, Venus is a barren, heat-ravaged rocky planet, with the average surface temperature over 460 °C, and little variation from day to night.

Venus has the slowest rotation of any planet. Measured by the stars, it spins once every 243 days (the Earth equivalent is 23h 56m 4s, called a sidereal day). Pair this with its 224.7 day orbit, it means that one solar day on Venus lasts 116.75 Earth days – not that you could see the Sun rising or setting, because of the cloudy atmosphere.

The surface of Venus is peppered with volcanoes, some of which are still active. Unlike Earth, its crust doesn’t have tectonic plates that move around, but it’s thought that there are global resurfacing events due to the release of built-up heat and pressure in the mantle, the last one 300-600 million years ago.

Fun fact! Venus does 8 orbits for every 5 that Earth does, meaning that Venus returns to almost the exact same part of the sky, at the same time of year, every 8 years. So, if you miss Venus snuggling up to your favourite star cluster, just wait 8 years for another chance.

Visit the Sir Thomas Brisbane Planetarium to learn more about our planets: https://bnecouncil.cc/4eDfKWw



📸: Wikipedia

Did you know? Asteroids can have rings and moons!

Chariklo is a small Centaur-class asteroid orbiting the Sun between Saturn and Uranus and was the first minor body found to possess a ring system, with two narrow rings.

Ida was the first asteroid discovered to have its own moon, Dactyl. Dactyl is a tiny, 1.4km moon with a similar composition to Ida.

Explore the wonders of the galaxy at the Sir Thomas Brisbane Planetarium: https://bnecouncil.cc/48NlCc4

📸: NASA - National Aeronautics and Space Administration

Our next feature is ‘U’ for ‘Uranus’. ✨

The 7th planet from the Sun, and the first one discovered since ancient times. The original 5 (Earth wasn’t initially understood to be a planet) were named after Roman gods, but Uranus’s name comes from the Greek sky god Οὐρανός (OO-rah-noss).

The 5 classical planets, from Mercury to Saturn, are easily visible with the unaided eye. Although, as Mercury is so close to the Sun it is the most challenging to see. Uranus hovers on the edge of visibility in a dark sky and can require binoculars to see.

German-born British astronomer William Herschel was a dedicated observer and telescope-maker in the 1700s and found Uranus while making a very detailed survey of star positions, on 13 March 1781. At first, Herschel thought he had found a comet, but calculations based on its slow motion against the stars showed it was probably a planet rather than a comet, which would likely have a more elliptical orbit. Uranus had been observed several times before, even as far back as 128 BC, but was always assumed to be a faint star.

Learn more about Uranus with our fun facts:
🔵 It is the first planet, other than Saturn, known to have a ring system,
🔵 The axis of rotation is tilted, with the planet almost “lying on its side”,
🔵 The seasons last on average 21 years, varying from 19.7 to 22.3 years,
🔵 Like Neptune, molecules of methane deep inside the planet could be ripped apart, with the carbon atoms possibly being crushed together to form tiny diamonds,
🔵 It is the coldest planet at about -224 °C at the cloud-tops,
🔵 The planet receives less than 0.3% of the amount of sunlight compared to Earth,
🔵 The moons are named after characters from the works of William Shakespeare and Alexander Pope.

Discover more about our planets at the Sir Thomas Brisbane Planetarium: https://bnecouncil.cc/4vIgS1i



📸: NASA - National Aeronautics and Space Administration

Look up and discover the beauty of our night sky this month! 🌌 Discover our Astro Highlights:

🔴 Throughout May: Find Venus low in the western evening twilight,
☄️5 and 6 May: The eta Aquariid meteor shower will fill our sky, but a bright waning Moon will hide the fainter meteors. The best chance of seeing the display will be in the last few hours of the night (especially between 4am and 5am),
🌙 19 May and 20 May: Lookout for an evening Moon-planet gathering with the crescent Moon beside Venus on the 19 May, and below Jupiter on the 20 May,
🌌 26 and 27 May: Mercury, Venus, and Jupiter will find each other in the evening twilight, though Mercury will be very low.

Did you know? Other than the Moon, Venus and Jupiter are the brightest objects in the north-western evening sky this month.

Explore our night skies with our experts at the Sir Thomas Brisbane Planetarium: https://bnecouncil.cc/4czil2r

📸: NASA - National Aeronautics and Space Administration

How many times has Neptune completed a full orbit around the sun since its discovery in 1846?
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1! Neptune takes 165 years to complete one full orbit around the Sun and only finished its first full post-discovery orbit in 2011.