Space and Astronomy News for the 19th of July 2025

The largest Martian Meteorite is auctioned by Sotheby's

Some cool space news this week was the auction of the largest known meteorite to have originated from Mars. Sotheby's in New York sold the hunk of space rock for USD$5.3 million, or somewhat over $8 million in local money.

The 25kg rock is a called NWA 16788 and was found in North West Africa, hence the name.

This looks like an ordinary rock to me. How do we know it's from Mars?

There's been nearly 80,000 confirmed meteorite finds on Earth. These are distinguished from "local" rocks by their composition and structure. This is often the result of many millions or even billions of years in space and a fiery journey to the Earth's surface. They're also identified based on where they're found, sometimes even polar regions where somewhat recently descended space rocks stand out from permanent ice and snow. 

Only 770 of these meteorites have been confirmed to have come from Mars.  They're different from other meteorites in a few ways. First of all, they're younger, having arrived from Mars after the red planet was impacted by a large body which threw parts of the surface into space. (Meteorites from elsewhere in the Solar System are often much older.)

Pockets of gas trapped in them match the atmospheric composition found on the surface of Mars by landers such as Viking and Curiosity. Their chemistry also doesn't match either Earth rocks or asteroids. 

If we have meteorites from Mars, why do we need to carry out a sample-return mission there?

We don't know when the event that caused them to be ejected into space happened or what part of Mars it came from.  The shock of having a space rock large enough to throw material not just into Mars orbit, but into the Solar System would have been vast. Any delicate structures would have been altered by this process.

A (tiny) part of a Mars meteorite at BINTEL

Any traces or fossils of ancient life, if it ever existed on Mars, would have likely been destroyed as well. NASA and other space agencies including the Chinese have plans for Mars surface landings with sample returns in the next decade. There's going to be some fascinating discoveries once we have proper samples of Mars rocks in Earth laboratories.  

Can I buy Mars meteorites? 

Yes. They are available. Big ones like this week's 25kg Mars rock might be worth millions, although smaller samples are a lot more affordable!

The Great Sydney Solar Eclipse - 3 years to go!

The 2017 Solar Eclipse in the USA (image via NASA/Aubrey Gemignan)

This coming week marks the three year countdown to the next Total Solar Eclipse visible in Australia which will occur on the 22nd of July 2028. 

It will cross right over Sydney as well as cutting a path across much of the central parts of the country.

Path of the 2028 eclipse. More info here.

While three years might seem a long way off, these events capture the world's attention and tourists will arrive from everywhere. You'll have to plan your travel well in advance to experience this amazing event!

Gilmour Space scrubs the Eris-1 launch again

A combination of weather and technical issues has again caused Gilmour Space to delay the launch this week of their rescheduled Eris-1 mission. 

This will go ahead, possibly in August.  There's an interesting article with some more background info here.

Cheers,

Earl White

BINTEL

19th July 2025