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Sagittarius 2021 ๐Ÿน heart ๐Ÿš€

A stick figure is lying on a crescent moon and looking up at the Sagittarius consellation

If you ever need to face the centre of our galaxy, just find the Sagittarius constellation. Sagittarius sits in an area of the sky that points to the heart of the Milky Way. And that beating heart is a supermassive black hole 4.6 million times the mass of the Sun. It’s called Sagittarius A* (Sgr A*) and it’s 26,000 light-years from Earth - close enough for us to see the hot gas that swirls around it. Sgr A* affects the orbits of nearby stars, which researchers can track to test things like Einsteinโ€™s general theory of relativity. A theory that’s still holding up after more than a century. ๐Ÿ’ช

#readingaboutastronomymakesyousmarter
#readinghoroscopesdoesnothing

Sources:

1. Zimmermann KA. Sagittarius constellation: Facts about the archer. Space.com. Available at: space.com/21653-sagittarius-constellation.html (Last updated: May 2017; Accessed: Nov. 2021).

2. Boen B. Supermassive black hole Sagittarius A*. NASA. Available at: nasa.gov/mission_pages/chandra/multimedia/black-hole-SagittariusA.html (Last updated: Aug. 2017; Accessed: Nov. 2021).

3. Blome C, Lepo K, Perez Y. Black holes: Sagittarius A* - Identifying our galaxyโ€™s supermassive black hole by tracking starsโ€™ orbits. ViewSpace. Available at: viewspace.org/interactives/unveiling_invisible_universe/black_holes/sagittarius_a (Accessed: Nov. 2021).

4. Taylor Tillman N and Bartels M. Einstein’s theory of general relativity. Space.com. Available at: space.com/17661-theory-general-relativity.html (Last updated: Jun. 2021; Accessed: Nov. 2021).

โœ๏ธ Edit: The authors of a recent paper are challenging the idea that Sgr A* is a black hole. They’re proposing that it might be dark matter (‘darkinos’). We’ll have to wait and see.

Scorpio 2021 ๐Ÿฆ‚ giant ๐Ÿš€

Two stick figures are sitting in the desert looking up at the Scorpio constellation

Of all the constellations, Scorpius the scorpion wins the prize of Looking-Most-Like-The-Thing-You-Are-Named-After. Kinda. Its brightest star is Antares, a red supergiant thatโ€™s the 15th brightest star in the night sky. It’s really big - if the Sun was a small coin on a basketball court, Antares would be almost the court’s width. Last night we saw it for the first time through our telescope. Nice. ๐Ÿ€

#readingaboutastronomymakesyousmarter
#readinghoroscopesdoesnothing

Sources:

1. Watson F. Scorpius. Beginner’s guide to the night sky, ABC Science. Available at: abc.net.au/science/starhunt/tour/virtual (Accessed: November 2021).

2. Johnson D. Meet Antares: The star that is not Mars. Sky & Telescope. Available at: skyandtelescope.org/observing/meet-antares-the-star-that-is-not-mars (Last updated: September 2020; accessed: November 2021).

3. 25 brightest stars in the night sky. NASA Science. Available at: science.nasa.gov/25-brightest-stars-night-sky (Last updated: June 2019; accessed: November 2021).

4. Scorpius constellation. The Nine Planets. Available at: nineplanets.org/scorpius-constellation (Last updated: August 2020; accessed: November 2021).

Libra 2021 โš–๏ธ old ๐Ÿš€

A stick figure is looking through a telescope at the Libra constellation

I just learned that one of the universeโ€™s oldest stars lies inside the Libra constellation - HD 140283, a.k.a. Methuselah. A recent study suggests it’s about 12 billion years old - thatโ€™s not that long after the Big Bang. One of the clues is itโ€™s low metallicity - it was born in a time when metals were rare and everything was made mostly of hydrogen and helium. Methuselah is around 200 light years away and you need binoculars or a telescope to see it. If you do, remember that the photons that land on your retina (splat!) were made inside an extremely experienced photon maker indeed. ๐Ÿ‘ต๐Ÿป

#readingaboutastronomymakesyousmarter
#readinghoroscopesdoesnothing

Sources:
1. Hubble finds birth certificate of oldest known star. NASA. Available at: nasa.gov/mission_pages/hubble/science/hd140283.html (Last updated: July 2013; Accessed: September 2021).
2. Plait P. Methuselah’s star is not older than the universe after all. But it’s still pretty frakking old. Bad Astronomy. Available at: syfy.com/syfywire/methuselahs-star-is-not-older-than-the-universe-after-all-but-its-still-pretty-frakking-old (Last updated: May 2021; Accessed: September 2021).
3. Tang J and Joyce M. Revised best estimates for the age and mass of the Methuselah star HD 140283 using MESA and interferometry and implications for 1D convection. Res Notes AAS 2021;5:117. Available at: iopscience.iop.org/article/10.3847/2515-5172/ac01ca (Accessed: September 2021).
4. Big Bang. Cosmos, Swinburne Centre for Astrophysics and Supercomputing. Available at: astronomy.swin.edu.au/cosmos/B/Big+Bang (Accessed: September 2021).

Virgo 2021 ๐Ÿ‘ฉ features ๐Ÿš€

A stick figure girl is lying down looking up at the Virgo constellation and talking to a warty toad wearing a wig. She says: I've been learning about the constellation Virgo - it doesn't look like much, but it has some cool features.  The toad replies: Like what?

The girl continues: My favourite is the 'Virgo Cluster' - a group of about 2,000 galaxies - mostly spirals. It's our closest cluster 'neighbour' - around 50 million light-years away. It's so big they reckon it'll eventually cause our little cluster, the Local Group, to slow down, reverse and join up with it.

There is an asterisk at the bottom of the panel that warns: Actual 'information' from serendipity-astrolovers.com. The toad adds: Well my astrologer told me my features are cool too. Like all Virgos, she said I have a frail chin, fleshy nose, poor skin condition, bent toes and a curious, awkward walk. And when I reach middle age, my dislike of exercise will give me a fat belly.

The girl looks amused and says: She got all that from your star charts huh?

Toad image credit: Reimar Gaertner.

Sources:
1. Virgo cluster. Cosmos, The SAO Encyclopaedia of Astronomy. Swinburne University of Technology. Available at: astronomy.swin.edu.au/cosmos/V/Virgo+Cluster (Accessed: August 2021).
2. Shu FH. Virgo cluster. Encyclopaedia Britannica. Available at: britannica.com/place/Virgo-cluster (Last updated: May 2013; Accessed: August 2021).
3. Virgo astrological signs, looks, physical features, style and other idiosyncrasies. Serendipity Astrolovers. Available at: serendipity-astrolovers.com/astrological-signs-2.html (Last updated: August 2021; Accessed: August 2021).

๐Ÿ”ญ ps. We now have some very stylish stickers and badges available (including a glitter telescope ๐Ÿ˜ฌ), plus some free cartoon wallpapers. All purchases go towards our science grant. ๐Ÿ”ญ

Our inaugural donation ๐Ÿ’ฐ ๐Ÿš€

Our Society is committed to making an annual donation to someone doing real science with stars and planets (versus the pseudoscience of astrology).

Weโ€™re pleased to report our inaugural donation has gone to the ANU Research School of Astronomy and Astrophysics Innovation Fund.

Itโ€™s not enough to buy a new Hubble, but we hope this small contribution helps them do the cool things they do. And weโ€™ll aim for more next year.

We are thankful to our members, who helped make this donation happen. Membership packs are available here and here.

Donation #1: ANU Research School of Astronomy and Astrophysics Innovation Fund

Aries 2021 ๐Ÿ love and fashion ๐Ÿš€

A cartoon ram says to a stick figure girl: Did you know that people born under Aries are going to be easier to love this year and should take their fashion inspo from Stella McCartney?

The girl replies to the ram enthusiastically: Did you know that researchers at the Palomar Observatory discovered a planet in the Aries constellation that has four suns orbiting it? Itโ€™s really big - about 10 times the mass of Jupiter. This four-star system is called โ€˜30 ARIโ€™ and itโ€™s 136 light-years away. If you could look up at the daytime sky from this planet, youโ€™d see a sun as well as two bright stars.

The girl adds with a smile: fyi, telling me stuff about your horoscope doesnโ€™t make you easier to love. The ram hangs its head and looks a bit ashamed.

Sources:
1. Boland Y. Stars Special: Your 2021 Horoscopes Are Here! Marie Claire. Available at: marieclaire.com.au/2021-horoscope (Accessed: Apr 2021).
2. Roberts LC et al. Know the Star, Know the Planet. III. Discovery of Late-Type Companions to Two Exoplanet Host Stars. AJ 2015;149(4):118.
3. Clavin W. Astronomers Identify a Quadruple Star System, 30 Ari. SciTechDaily. Available at: scitechdaily.com/astronomers-identify-quadruple-star-system-30-ari (Last updated: Mar 2015, accessed: Apr 2021).
4. Zimmerman KA. Aries Constellation: Facts About the Ram. Space.com. Available at: space.com/17052-aries-constellation.html (Last updated: Mar 2019, accessed: Apr 2021).