Pluto's Big Night & a Sharper Look at M87's Black Hole | Today's Space News

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Anna: Welcome to Astronomy Daily. I'm Anna.

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Avery: And I'm avery. It's Monday, the 27th

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of July, 2026, and tonight,

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the smallest headliner we've had in a while

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gets top billing.

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Anna: That's right. Our lead is a world you

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cannot see without a decent telescope,

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one that half of the astronomy community will

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tell you isn't even a planet. And today is

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its brightest night of the year. Pluto

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reaches opposition. We're going to spend some

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proper time there. The discovery, the

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demotion that people are still arguing about,

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and the frozen world New Horizons actually

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found waiting for us.

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Avery: Then, um, three quick stops. A crew comes

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home after 241 days in orbit.

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New modeling suggests the most common planet

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in the galaxy may be hiding oceans of molten

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rock. And astronomers have taken the famous

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first ever black hole image and pulled a

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whole new layer of physics out of it.

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Anna: And we'll close where we always do, under the

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sky north and south, with a M meteor

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shower that's putting on its best show for

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our Southern Hemisphere listeners. Let's get

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into it.

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So, Avery set the scene for me. If someone

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walks out tonight and looks up, are they

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going to see Pluto?

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Avery: Honestly, no. Not with their eyes and not

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with a pair of binoculars. Tonight, Pluto

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sits directly opposite the sun in our sky,

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over in the constellation Capricornus. That's

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what opposition means. Earth is passing

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between Pluto and the Sun. So Pluto rises

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at sunset, sits highest around midnight,

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and it's fully lit and as close to us as it

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gets all year. A, uh, touch under 35

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astronomical units. So roughly 35

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times the Earth's sun

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Anna: distance, and that's as good as it gets.

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Avery: And it's still faint, painfully

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faint. We're talking about magnitude 15,

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to put that in human terms. It's millions of

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times dimmer than the faintest star you can

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pick out on a dark night. You realistically

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need an 8 inch telescope and a good star

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chart. And even then, Pluto looks like

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a star, a dot that only gives itself away

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because it shifts position over a

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Anna: couple of nights, which is exactly how it was

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found in the first place. Let's rewind.

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Because the Pluto story is one of the great

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underdog tales in astronomy.

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1894, Percival Lowell, the same

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wealthy Bostonian who convinced himself

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Mars was covered in canals, sets up an

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observatory in Flagstaff, Arizona, and

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becomes obsessed, um, with a planet X he

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was sure was tugging on the orbits of Uranus

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and Neptune.

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Avery: And, um, he never found it. He died in 1916,

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still hunting.

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Anna: He did the search, went cold, then

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restarting. And in 1929 the

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job landed on a 23 year old Kansas farm

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boy with no colonies college degree named

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Clyde Tombaugh. His method was brutal,

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painstaking work. Photograph the same patch

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of sky on different nights. Then flick

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between the two plates in a machine called a

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blink comparator, looking for the one dot

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out of hundreds of thousands that moved.

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Avery: That is the definition of patience.

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Anna: On the 18th of February 1930 he

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found it. And here's a detail I love. The

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name didn't come from an astronomer. It came

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from an 11 year old English schoolgirl,

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Venetia Burney. Over breakfast she

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suggested Pluto, the Roman God of the

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underworld, fitting for a cold, dark,

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distant world. And the first two letters, P

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and L also happen to honor Percival

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Lowell. It stuck.

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Avery: So for 76 years, Pluto is the ninth

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planet. It's on every classroom wall, um,

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every lunchbox, every mobile over a

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cottage. Then 2006 happens.

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Anna: Then 2006 happens. And this is

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the part people still get heated about. So

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let me try to be fair to both sides because

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there genuinely are two good sides.

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The trouble started in the years before when

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astronomers began finding other icy

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bodies out past Neptune in a region called

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the Kuiper belt. And in 2005

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a team found Eris, which at the time

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looked to be bigger than Pluto.

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Avery: And that's the crunch. If Pluto's a planet,

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is eris planet number 10? What about the

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next 20 objects we

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Anna: find out there exactly the corner they were

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backed into. So in August

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2006, the International Astronomical

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Union voted on a formal definition of planet

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for the first time. Three rules. It has to

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orbit the Sun. It has to be roundish under

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its own gravity and the killer it, it

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has to, uh, have cleared its neighborhood of

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other debris. Pluto passes the first two

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easily, but it shares its zone with all that

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Kuiper Belt material. So it fails the third

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reclassified as a dwarf planet. It

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even got a minor planet catalog

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Avery: number 134340,

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a demotion with a filing number.

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Ouch. Not everyone accepted it,

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not at all.

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Anna: And this is the bit I want listeners to sit

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with because it's not settled science. It's a

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definition. And definitions are choices.

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The loudest objection comes from planetary

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scientists and Alan Stern, who leads the New

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Horizons mission, is the most prominent.

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Their argument is roughly clearing the

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neighborhood is a strange test because it

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depends on where an object is, not what it

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is. Put Earth out at Pluto's distance and

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Earth wouldn't clear that huge orbit either.

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They prefer a geophysical definition if

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it's big enough for gravity to pull it round.

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And it's not a star, it's a planet, full

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stop. By that logic, Pluto is a planet, and

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so are, uh, a dozen other round worlds.

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Avery: And the counterargument, the dynamical

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camp.

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Anna: The folks who wrote the IAU rule say a

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definition has to be useful. And anything

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round gives you potentially hundreds of

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planets, which tells you nothing about how

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the solar system is actually organized.

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Clearing your orbit captures something real.

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The eight major planets are gravitationally

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dominant and the Kuiper bell objects simply

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aren't. So it's genuinely a values question.

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Do you classify by the object itself or by

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the role it plays in the system? Reasonable

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people land differently.

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Avery: And then, as if the universe wanted to make

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everyone regret the timing, New

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Anna: horizon shows up the best twist in the

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whole saga. The probe launched in January

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2006, seven months before the vote.

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So it left Earth as a mission to the ninth

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planet and arrived in July 2015

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at a dwarf planet. And what it sent back

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demolished the idea that small and far means

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dull and dead.

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Avery: This is my favorite part. Because we expected

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a cratered frozen billiard

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Anna: ball, we got a stunningly complex

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active world. There's a vast bright plain of

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frozen nitrogen sputnik plantina that

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sits inside a uh, giant heart shaped feature

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the whole Internet fell for. And that heart

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isn't static. The nitrogen ice is slowly

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churning, convecting like a lava lamp in

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ultra slow motion. Which is why it has almost

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no crater. The surface is being

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resurfaced. There's mountains of water ice

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as tall as the rockies. Because at Pluto's

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temperatures, water ice is hard as rock. A

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thin blue tinged nitrogen atmosphere with

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layers of haze and a real possibility of a

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liquid water ocean sloshing beneath the

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crust.

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Avery: A subsurface ocean on um, a world people were

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arguing wasn't important enough to be a

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planet.

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Anna: Which is the poetry of it, isn't it? The

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label we hang on Pluto changed nothing about

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Pluto. It's exactly as fascinating as the day

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before the vote. And it's not alone out

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there. It has five moons of its own. The big

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one, Charon, so large that the two of them

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orbit a point in empty space between them

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Like a slow cosmic waltz.

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Avery: So tonight, when it's at its brightest and

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best place for the year, that faint 15th

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magnitude.in Capricornus is a churning, hazy,

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possibly ocean bearing world with a heart on

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its face.

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Anna: That's the one and whatever you want to call

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it, planet, dwarf planet, Kuiper belt object.

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Tonight is Pluto's night. We'll tell you

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exactly where to point a scope in the sky.

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Watch. Clyde Tombaugh, by the way, passed

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away in 1997. And new horizons

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carried a small portion of his ashes on that

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flyby. He got to visit the world he found.

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Avery: Okay, I'm not crying. You're crying.

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Lets bring it back to Earth literally.

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Speaking of coming home, three people did

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exactly that yesterday on, um, Sunday, a

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Soyuz MS.28 capsule parachuted down

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onto the steppe of Kazakhstan, bringing NASA

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astronaut Chris Williams and Roscosmos

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cosmonauts Sergey Kut Sverchkov and Sergey

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Mikhayev back after 241 days

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aboard the International Space Station.

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Anna: 241 days put a number on what

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that actually is.

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Avery: Nearly eight months, around

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3,885 laps of the

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Earth and more than 102 million miles

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traveled, all while effectively standing

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still in orbit. They launched back on the

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27th of November, American Thanksgiving. So

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they've missed an entire summer and winter

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depending on your hemisphere.

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Anna: And it was a first flight for two of them.

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Avery: It was first mission for Williams and for

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Mikhayv. Gutsverchkov's the veteran. He's

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now passed 425 days in space

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across two flights. And I want to flag the

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quiet significance here. A, uh, NASA

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astronaut and two Russian cosmonauts riding

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home together in a Russian capsule. Whatever

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the politics on the ground, the crude side of

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this partnership just keeps functioning, seat

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swaps and all.

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Anna: What was Williams actually doing up there?

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It's easy to forget these are working science

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missions, not just endurance feats.

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Avery: Right. And his work is genuinely down to

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Earth in its aims. He supported research into

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novel cancer therapies which benefit from the

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way proteins and cells behave in microgravity

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and into manufacturing high performance

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materials, the kind used in advanced

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electronics and computing that you can make

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more plainly without gravity pulling

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everything around. The pair of cosmonauts

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also did a spacewalk back in May to install a

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solar radiation instrument on the station's

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exterior.

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Anna: And the handover keeps the station rolling

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seamlessly.

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Avery: Command passed to NASA's Jessica Meyer as

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Expedition 74 became 75 and

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a fresh crew. Anil, uh Menin and two

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cosmonauts arrived earlier this month to keep

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the lab staffed. The hard part now,

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ironically, is gravity. After eight months,

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just holding your own head up is exhausting.

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The readjustment takes weeks.

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Anna: Welcome home to the three of them now from

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people orbiting one planet to the most common

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kind of planet in the entire galaxy.

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Avery: Moving on to story three, sub Neptune's

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clouds of Rock, oceans of magma. What's this

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all about?

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Anna: Here's a fact that still catches me out. The

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most common type of planet in the Milky Way

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is a type we don't have. It's the sub

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Neptune. Bigger than Earth, smaller than

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Neptune. There's nothing like it in our solar

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system, yet they turn up everywhere else. Out

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of more than 6,000 confirmed exoplanets, well

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over 2,000 are, uh, sub Neptunes.

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Avery: And we barely understand what they're made

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of.

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Anna: That's the frustration. They could be small,

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rocky cores wrapped in thick hydrogen

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atmospheres, or they could be water worlds,

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volatile, rich, drowning in water and carbon

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molecules. And we can't easily tell because

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even the James Webb telescope can only read

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the very top of the atmosphere. And these

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atmospheres are deep and hazy. New

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modeling from a team at Arizona State,

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recently published, offers a clever way

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through. And it puts clouds at the center of

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the story.

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Avery: Clouds on a planet where weather must

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mean something wild.

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Anna: Wild is the word deep down, where the

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pressure is crushing. The team modeled clouds

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made of vaporized rock and salt. Think

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aluminum oxide, iron silicates,

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potassium chloride. Actual mineral

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clouds. And here's the key finding those

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clouds act like a blanket. They trap heat

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trying to escape from the interior, which

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pushes the boundary between the atmosphere

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and the solid body to temperatures high

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enough to melt rock.

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Avery: So beneath the clouds, you might have an

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ocean of magma, a global magma

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Anna: ocean in the cloudy scenario. In the cloud

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free version, that boundary is cooler and

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might stay solid. Same planet from the

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outside, two completely different interiors,

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depending on the clouds. And that matters for

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us for a very practical reason. It changes

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how we interpret what Webb sees, and it feeds

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directly into which of these worlds we bother

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calling potentially habitable.

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Avery: To be fair, this is modeling, not a direct

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observation, completely fair.

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Anna: This is simulation work, pointing observers

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at what to look for. Not a photograph of

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magma, but it reframes clouds from being just

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an annoying smudge that ruins our data into

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an active ingredient, shaping the whole

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planet. For the galaxy's most common world,

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that's

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Avery: a meaningful shift from world we're modeling

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to a monster we've actually photographed.

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Let's go to M M87.

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Anna: Next up, story four, a sharper look at M

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M87's black hole.

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Avery: Cast your mind back to 2019, that

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first ever image of a black hole, the orange

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donut. That was M M87,

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the supermassive black hole at the heart of

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a giant galaxy in Virgo, about

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55 million light years away. Weighing

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in at around six and a half billion

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suns. That Single image was one of the

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defining science pictures of the decade.

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Anna: And now a team has gone back to the data and

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done something new with it.

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Avery: They have. Researchers led by the Shanghai

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Astronomical Observatory with international

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collaborators have produced the first

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spatially resolved dual frequency spectral

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map of M M87. And I know that's a mouthful,

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so let me unpack it because it's clever.

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Anna: Please. Dual frequency spectral map needs a

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translation.

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Avery: Think of it like this. The 2019 picture was

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a single color photo of the ring. What this

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team did was image the black hole at two

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different radio wavelengths, 1.3

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millimeters and 3.5 millimeters, using the

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Event Horizon Telescope and a partner network

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called the GMVA from observations back in

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2018. Then they compared them point

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by point to see how the color of the glow

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changes as you move outward from the center.

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That comparison is the spectral index, and

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mapping it across the ring had never been

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done before.

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Anna: And what did the map show?

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Avery: A, uh, clear structure. The signal is one

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character inside the bright ring, and it

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steepens, changes flavor as you move outward,

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with the transition landing right at the ring

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itself, about 30 micro arcseconds out.

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And that's the headline. It tells us the ring

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we photographed in 2019 isn't just a trick of

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where the light happens to glow. It's tied to

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a real physical change in the plasma right

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around the event horizon.

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Anna: So why does that matter beyond. Nice. A, uh,

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sharper map.

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Avery: Because reading a black hole means untangling

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two things that are mixed together. The pure

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warping of space by gravity and the messy

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physics of superheated plasma spiraling in.

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The researchers say looking at multiple

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wavelengths lets them start to separate those

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two. That's the path to understanding how

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these monsters feed, how they fire off those

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enormous jets, and eventually to a cleaner

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test of Einstein's general relativity. It's

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the difference between having a portrait and

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starting to read the biography.

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Anna: A portrait to a biography. I'll take that.

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And on that note, let's step outside,

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because it's skywatch time. And as always,

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wherever you are on the planet, we've got

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you. Avery, you take the south, I'll take the

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north, and we'll meet in the middle at Pluto.

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Avery: Deal. Southern hemisphere first. And friends

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down south. This is your week. The Southern

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Delta Aquarids are peaking. This is a shower

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that genuinely favors the south. The radiant

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in Aquarius climbs high after midnight for

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you. And under a dark sky, you could see

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something like 20 to 25 meteors an hour.

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No equipment, just a reclining chair, a wide

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Open view and some patience while your eyes

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adapt.

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Anna: And there's a comet. For the early risers,

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There is Comet

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Avery: 10P Tempel 1 low in the pre

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dawn sky. It's uh, a binocular or small

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telescope object rather than a naked eye

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00:16:30.240 --> 00:16:33.040
showpiece. But here's a southern bonus. It's

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diving southward through August, so our

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Southern Hemisphere listeners get the better

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and improving view. Northern folks, catch it

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now before it

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Anna: drops away from you Northern Hemisphere. Your

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headline is a star with a wonderful name.

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Look high toward the north for the

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constellation Cepheus. It looks like a

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child's drawing of a house. And near the

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bottom of that house sits Mu Cepheii,

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better known as Herschel's Garnet Star. It's

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one of the reddest stars you can see with the

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naked eye. A, uh, bloated red supergiant so

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vast that if you dropped it where the sun is,

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its surface would swallow Jupiter.

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Binoculars really bring out that deep ember

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color. And you northern observers get the

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Delta Aquariids too, just lower down toward

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your southern horizon.

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Avery: And now the meeting point, the one we teased

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at the top, Pluto.

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Anna: Pluto's at opposition tonight over in

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Capricornus, which is beautifully placed for

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the Southern Hemisphere high overhead and

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00:17:29.010 --> 00:17:31.690
perfectly workable low to mid northern skies

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too. Now the honest part. At

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magnitude 15, this is a genuine

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00:17:36.849 --> 00:17:39.210
challenge. You'll want at least an 8 inch

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00:17:39.210 --> 00:17:41.970
telescope, a detailed finder chart, and the

431
00:17:41.970 --> 00:17:44.850
trick is patience. Sketch or photograph

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00:17:44.850 --> 00:17:47.370
the star field two or three nights running

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and watch for the one star that moves. That

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mover is Pluto. It is the ultimate

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bragging rights target.

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Avery: And, um, there's a catch tonight for

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00:17:56.240 --> 00:17:56.520
everyone.

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Anna: There is a big bright moon, about

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00:17:59.720 --> 00:18:02.560
95% full, washing out the sky

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00:18:02.560 --> 00:18:05.200
all week. That won't bother the Garnet star

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00:18:05.200 --> 00:18:07.480
or the brighter meteors much, but it makes

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faint Pluto even harder. If chasing

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00:18:10.280 --> 00:18:12.800
Pluto is your goal, wait for it to clear the

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00:18:12.800 --> 00:18:15.560
worst of the moonlight or give it a week. Oh,

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and Saturn is rising after midnight over in

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Pisces for both hemispheres, rings and all.

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A lovely consolation prize in any scope,

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00:18:24.210 --> 00:18:25.250
north or south.

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Avery: There's something up there for you tonight.

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Anna: And that's Astronomy daily for Monday

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00:18:30.130 --> 00:18:32.930
27th July. A faint little

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world having its big night, A crew safely

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home, magma oceans on the galaxy's

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commonest planet, and a, uh, sharper look at

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the first black hole we ever photographed.

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Avery: You can find show notes, links, and every

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00:18:46.090 --> 00:18:49.090
past episode@astronomydaily.IO

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and the observant amongst you will notice

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that we have a brand new website today, so

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00:18:53.560 --> 00:18:55.440
make sure you check it out. And we're

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AstroDaily Pod Across Social. If

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00:18:58.160 --> 00:19:00.840
tonight's Pluto story settled or restarted,

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an argument in your house, we'd love to hear

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it.

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Anna: For Avery, I'm Anna. Whatever you decide to

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call Pluto, clear skies.

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The stories.

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Mhm.

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Avery: We told.