Space and Astronomy News for the 21st of June 2025

First images from the Vera C. Rubin Observatory are due this coming week

Astronomers, from complete beginners to renowned academics, are excitedly waiting for the release of the first images from the Vera C. Rubin Observatory in an event they're calling the "First Look". (It will happen at 1.00am on the 24th of June 2025 Sydney time, but I'm sure many will be staying awake for it!)

We've talked about this new observatory in several articles in recent times.  It's certainly not the largest telescope ever built. Even larger telescopes are under construction and will become operational in the coming years. What's so exciting about the Vera C. Rubin Observatory is the amount of astronomical information it will produce.  

The Vera C. Rubin Observatory during the commissioning phase

The telescope's unique optical design will allow its 8.4 metre primary mirror to see a 3.5 degree field of view. By comparison, the full Moon is about 0.5 degrees wide. It images the sky with the largest digital camera ever constructed, the 3.5 tonne Legacy Survey of Space and Time (LSST) with 3,200 megapixels.  This combination will photograph the entire sky visible from its location in Chile every three nights. This means when fully operational, the Vera C. Rubin Observatory will generate more astronomical data in a single month than all other telescopes throughout history - combined!

We'll of course be showcasing these new images next week and touch on some of the science objectives the new facility hopes to explore in the next decade.

SpaceX Starship explodes. On the ground this time, not in flight

We'd all hoped that SpaceX's Starship program would be producing successful launches with the largest rocket ever built busily preparing to carry heavy payloads into orbit and further towards Mars in the coming years. The recent launches of Starship, while producing precious engineering data according to SpaceX, have seen many failures and explosions. The most recent one happened this week while the Starship 36 was undergoing testing on the ground in Texas.

Starship 36 explosion in Texas this week.

Luckily, there were no injuries although there was extensive damage to the facilities. This latest setback is making Elon Musk's projected timeline for uncrewed exploration of Mars before the end of this decade and landing humans on the red planet in the first part of the next even more difficult to achieve. I asked the president of the Mars Society Australia, Dr. Jon Clarke, why timing is critical when going to Mars.

"This is problematic for Musk’s Mars ambitions because, unlike for an Earth orbiting mission, where failure means you can try again as soon as you are able to launch again, Mars missions can depart for Mars only when the launch window opens.  If Musk misses that he will have to wait for 26 months until the next window is available.  The 2026 window will be in November-December.  The one after that is December 2028-January 2029.  This means that Musk has 17-18 months to orbit, recover, and reuse Starship and successfully and reliably along with its booster, demonstrate and then bring into service the tankers needed to refuel the Starship going to Mars, be able to perform the necessary orbital refuelling, all before the end of next year."

Astronomers find most of the Universe's missing matter

If you've ever wondered where most of the "stuff" or baryonic matter that makes up the Universe is located, you've probably thought most of it would be clumped together in the stars, planets and ever nebulae that form galaxies, the with the vast distances between them empty. (Baryonic matter is the everyday ordinary matter you're familiar matter. The device you're reading this on is made of baryonic matter for example.)

Rather we've known for many years that the majority of ordinary matter is missing. There were estimates, but no way of determining the amount or location with any accuracy.  There'd been various attempts to do so using quasars, but thin, high temperature gasses could not be seen by telescopes. 

Astronomers found that Fast Radio Bursts (FRBs) can be used to measure baryonic matter but had trouble finding locations. Fast radio bursts are high intensity, short bursts of radio waves from galaxies. We're not sure what they are exactly. How intense? They can emit as much energy as they Sun puts out in several days over a period of just a few seconds. 

By investigating 60 FRBs, including the most distant one ever observed at over 9 billion light years away, they've been able to map the space between galaxies and found the missing matter in the regions between them. This is called the intergalactic medium (IGM).

"The decades-old 'missing baryon problem' was never about whether the matter existed," said Liam Connor, CfA astronomer and lead author of the new study. "It was always: Where is it? Now, thanks to FRBs, we know: three-quarters of it is floating between galaxies in the cosmic web." In other words, scientists now know the home address of the “missing” matter.

Bottom line - about 76% of the ordinary matter in the Universe is in the IGM, floating around in the space between galaxies 

You can read more about this announcement here. 

Astronomers have now found the largest Oort cloud comet has started to become active

Many would know about the Oort Cloud, a large region between the outer extremities of the Solar System that extends most of the  way to the nearest star system. It's thought to contain billions of objects bigger than 20km wide and trillions of bodies more than a kilometre in size.

Occasionally, one of these bodies are disturbed from their position in the Oort cloud and start heading towards the inner Solar System. These Oort Cloud comets haven't been into the inner parts of the Solar System where the planets and the Sun are located and can result in some displays so bright they can even be seen during the day.

Comet C/2014 UN271 (Bernardinelli-Bernstein) was first found in archival data in 2024, and has now been observed to be active by astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) while it was some 16.6 times the distance from the Sun and the Earth. What's amazing about this Oort Cloud comet is its size, at about 140km across. This is more than 10 times the size of most comets we've ever observed. 

An illustration of Comet C/2014 UN271. Image via NSF/AUI/NSF NRAO/M.Weiss

C/2014 UN271 was found to have jets of carbon monoxide gas and producing heat emissions while the comet was still at a large distance from the Sun.

“These measurements give us a look at how this enormous, icy world works,” said lead author Nathan Roth of American University and NASA Goddard Space Flight Center. “We’re seeing explosive outgassing patterns that raise new questions about how this comet will evolve as it continues its journey toward the inner solar system.”

Sadly for astronomers this giant comet won't be visible with just your eyes when it makes its closest approach to the Sun in January 2031. It will be some 10.9 AU or about the distance between the Earth and Saturn and it will not enter the inner Solar System.

More about this discovery here.

In All, a Rather Ho-Hum Week...

Just the usual: we’ve found most of the missing matter in the Universe, the biggest astronomical data stream in history is about to open, the largest comet ever seen is headed our way (sort of), and Starship exploded again.

Cheers,

Earl White 

BINTEL

21st June 2025