Space and Astronomy News for the 14th of June 2025

Should we paint satellites black to help astronomers? Well, maybe.

Many of our customers have found trails from satellites appearing as streaks in their astro images. While the odd one or two might look interesting, more satellites will make it harder and harder to take clear, long exposure photos of night sky.

There are around 8,000 satellites in low Earth orbit (LEO) at the moment, and this figure is expected to rise to over 60,000 in the next five years.

It's an even more serious problems for professional observatories. We've talked about the "first light" of the Vera C. Rubin Observatory in the coming weeks. This remarkable new observatory will image the entire sky visible from its location every few nights. Estimates are that up to the 40% of what it captures will be affected by trails in long exposures left by satellites.

An example of what satellites can do with an astro photo of the Milky Way. Image via Bernt Olsen

What we see when satellites leave streaks across images or when we spot them in the evening sky is sunlight reflecting from their surfaces. They don't emit light themselves. 

Given this, one solution would be to simply paint satellites so they don't reflect light. You've probably seen matt black cars, caravans or even buildings in daylight and while they appear darker than their surroundings, they're still visible as they're still reflecting some light.  There are special coatings that reflect almost no light and can make an object practically disappear from view. Could this be the answer for astronomers?

Once such coating is Vantablack 310 from Surrey NanoSystems. This reflects around 2% of the light that fall on it. Made from carbon nanotube arrays, this coating is also able to handle the tough conditions found in orbit. 

The company is teaming up with researchers from the University of Surrey to test how effective Vantablack 310 is hide the reflections from satellites. The coating will be trialled on Jovian 1, the first satellite mission from JUPITER – the Joint Universities Programme for In-Orbit Training, Education and Research due to launch in 2026.  It's certainly a promising way to solve a major problem facing astronomers of all types. Companies like SpaceX have identified this as problem and it's something they're "working on" for both optical and radio astronomers.

Check out more on this project here.

If you've never seen something painted in Vantablack or similar, it's a bit freaky. Our brains can't really process looking at something with no light reflecting from it. It makes things appear like a strange void with no details.

South pole of the Sun seen for the first time

Seen for the first time this week was the south pole of the Sun, a region previously unexplored by spacecraft. 

The region around the Sun's south pole. Image via ESA & NASA/Solar Orbiter/EUI Team, D. Berghmans (ROB)

The European Space Agency's Solar Orbiter spacecraft has provided a unique perspective of our nearest star thanks to a change in the plane of its orbit around the Sun. On the 23rd of March, it took this image from an angle some 17 degrees south of the Sun's equator.  There will be further changes to the orbit of Solar Orbiter, so more detailed images of these regions will be on the way in the future. 

They will add to our understanding of the Sun by helping us learn more about is cycles, magnetic fields and more. Until now, all the images of the Sun have been from the ecliptic plane, or the same angle the Earth and major Solar System orbit around. 

“Today we reveal humankind’s first-ever views of the Sun’s pole,” says Prof. Carole Mundell, ESA's Director of Science. “The Sun is our nearest star, giver of life and potential disruptor of modern space and ground power systems, so it is imperative that we understand how it works and learn to predict its behaviour. These new unique views from our Solar Orbiter mission are the beginning of a new era of solar science.” 

You can read the full news release and check out some more images here. 

The strange workings of the "Bunny Ears" galaxy

Astronomers lead by Harrison Souchereau and Jeffrey Kenney from Yale University have observed a strange galaxy in the Coma cluster, some 300 million light-years away.

A Hubble Space Telescope image of NGC 4858, with orange tendrils overlayed showing the "bunny ears" and inner tail taken by the ALMA radio telescope

Dense galactic clusters like the collection of galaxies in the Coma formation are some of the largest and most extreme bodies we've observed in the Universe.  All galaxies are moving on their own path, including our own Milky Way. Interactions with other galaxies will change their shapes or even merge with together as they get close over vast timescales.  In dense clusters, they can even be torn apart by other members and this is what appears to be happening with NGC 4858. 

Interactions with other galaxies cause extreme outside pressures (called ram pressure or “wind”) and this can strip away part of a galaxy’s interior gas. 

“This galaxy, NGC 4858, is traveling very quickly through the Coma cluster,” said Souchereau, a doctoral student in Yale’s Graduate School of Arts and Sciences and first author of the new study. “It is effectively in a wind tunnel, and its gas is in the process of being stripped away by the wind.”

This stripping away of gases causes this galaxy to have its jellyfish shape and unique "bunny ears". It also has features from fallback. This is where is gasses are pulled away from the galaxy but don't have enough velocity to escape the galaxy's gravity and fall back elsewhere into the galaxy.

Read more at Yale here.

Another example of the vast array of galactic wonders that make up the visible Universe. 

Winter Solstice next Saturday

Next week we'll be chatting about the Winter Solstice, the shortest day of the year.

Cheers,

Earl White 

BINTEL 

14th of June 2025