The Grand Eclipse Expedition of 2023

by

Richard (Rick) Tonello

Chief Astronomer GDC Observatory

On the 20^th April 2023, along the sun drenched coastline of the Cape Range National Park, the Solar System will put on a spectacular show that will attract tens of thousands of people from across Australia and the world.

This celestial event will showcase the precision clockwork of the Solar System as the Sun, Moon and Earth perfectly align to create the spectacular phenomenon known as a Total Solar Eclipse.

Starting in the Great Southern Ocean, the shadow of the Moon will race across the surface of Earth at over 2700Km/h, skim over the Exmouth Peninsula and race northward from the Australian continent toward Timor-Leste and the Pacific Ocean.

For people along the narrow “Line of Totality” they will witness the Moon completely cover the blinding disc of the Sun revealing the complex structure of the Solar Corona. For a brief 62 seconds, observers will be plunged into an eerie twilight and the sky looking like a bullet has pierced its familiar continuum.

While there is a Total Solar Eclipse every 18 months somewhere around the world, this eclipse is special. The 2023 event is a rare Hybrid Eclipse that occurs once every decade. A Hybrid Eclipse is where the distance between the Earth and Moon is so finely balanced, that the curvature of Earth influences how much of the Moon covers the disc of the Sun. From the starting point in the Great Southern Ocean any observers will see an Annular Solar Eclipse, from Exmouth observers will see a Total Solar Eclipse.

Astronomers from the Gravity Discovery Centre Observatory will be on an expedition to Exmouth to observe, photograph and live stream the entire Total Solar Eclipse from the line of totality.

Live images will be provided from two, specialised Solar Telescopes and high-resolution cameras. One telescope will observe the Photosphere (Light Sphere), the surface of the Sun, while the other telescope will observe the Chromosphere (Colour Sphere), the dynamic layer located above the photosphere.

The broadcast provided by the GDC Total Solar Eclipse Expedition will be broadcasted to their FaceBook Page and YouTube Channel.

Local Media, social media and other organisations will pick up the GDC Observatory Total Solar Eclipse broadcast on the day of the Eclipse. Organisations such as Tourism WA, the Museum of Western Australia, the Singapore Science Centre, and to the Yagan Square Multimedia Screen are just a few of the organisations to utilise the live stream.

Those who are not observing from the Path of Totality will observe a Partial Solar Eclipse. Depending on the distance of the Observer from the path of Totality, the less of the Sun’s blinding disc will be obscured by the Moon.

Observers from Perth will witness a little over 70% of the Sun’s disc obscured by the Moon. Even though a majority of the Sun’s disc is covered, it is still dangerous to observe without the proper eye protection.  Never look directly at the Sun, even during the Partially Eclipsed phases. Even a 99% obscured Sun is enough to cause Solar Retinopathy (irreversible eye damage). Always use approved Solar Viewing Equipment (Eclipse Glasses) with the ISO 12312-2:2015 markings.

There are many ways to enjoy the Partial Eclipse through indirect viewing such as Pin-hole cameras, Camera Obscuras, kitchen colanders and Live streaming services.

There are many sources of information regarding Safe techniques to observe the Total and Partial Solar Eclipse such as the NASA, Gravity Discovery Centre & Observatory and Astronomical Society of Australia websites.

Through public education and correct information, let’s make this a date to remember for all the right reasons.

Ok so my suggestion to name this object LGM (Little Green Men) 2 was declined by my team Haha but we still aren’t 100% sure that these objects are Magnetars, and to avoid any potential conspiracy addicts (if you’re reading this) going into overdrive right now, it’s not aliens, my LGM 2 reference is a joke and ode to the original (half-jokingly name) LGM 1 which was given to the first Pulsar signal discovered before they knew it was a pulsar.

My Research team at CIRA (Curtin Institute of Radio Astronomy) has found a mysterious signal in Space, it is what we call a slow transient, transient meaning it turns off and on and slow meaning well… it does this slowly.

This signal was actually recorded in 2018 by the MWA Telescope but not discovered until 2021 when an Honours student-led by Curtin Astrophysicist “Natashia Hurley-Walker” was combing through old Archive records and stumbled upon this mystery signal. It turns on for 1 minute and then off for just over 18 minutes which would indicate it rotates once every 18 minutes and that’s odd, Reasons for which I’ll explain further in the article. The team has spent over a year since following up with further observations with the MWA, Parks Telescope in NSW, and NASA’s Chandra X-ray Observatory but here’s the kicker, the signal was only active for 3 months between February – March 2018 and has since turned off and hasn’t been detected since.

The team has also tirelessly looked through the last 10 years of observations from the MWA looking for this signal but to no avail, so it randomly turned on for what seems to be the first time in February 2018 and turned off a few months after and hasn’t been seen since. Weird!

This is an image of our Galaxy in radio light with the position of the discovered object highlighted. Credit: ICRAR.

So, then what’s a Magnetar? A Magnetar is a Neutron star! These objects are the leftover collapsed dense cores of giant stars after the star explodes in a supernova! The core itself is mainly all Neutrons packed tightly into a ball with some Protons and Electrons in there that survived the collapse. Stars are already spinning, but when the star explodes and its core collapses, this causes it to spin faster and faster as it gets smaller, this is due to the conservation of angular momentum (think of a figure skater spinning on ice, they speed up as they draw in their arms).
This also makes the magnetic field skyrocket up in strength to a billion times stronger than our own Sun’s magnetic field! That’s strong enough to erase your credit card from a 100,000Km away! Magnetars are the most magnetic objects in our universe.
These Neutron stars are Dense, which means they have terrifyingly strong gravity! A single cubic Cementer of Neutronium (which is what Neutron stars are made up of) would outweigh Mount Everest!

Now only around 10% of all neutron stars turn into Magnetars, there is also another type of Neutron star that spins fast and as they spin, they produce beams of energy (Light) out of their North and South Magnetic poles, these objects are called Pulsars! These dead stars spin and as they spin, these beams of light turn with it (think of a lighthouse) when the beam of light turns and flashes at the earth, we see this pulse of light and can detect them via Radio Telescopes, but although rarer, Magnetars can also produce these Beams!
So, recap, all Pulsars and Magnetars are simply Neutron stars but with added more unusual properties!

What’s most important now is that we are not 100% sure what causes these Neutron stars to produce these emission beams. We do know that it’s to do with their strong magnetic field coupled with their fast spin that accelerates electrons on their surface & above its surface up the open magnetic field lines and well that’s what makes this discovery weird! At a spin of 18 Minutes per hour, that’s insanely slow for these objects and as far as our understanding goes, this just isn’t fast enough to produce the beams that we are detecting!