Three of a Kind

0:01 Speaker 1: Picture an asteroid. You're probably imagining a potato one lump of rock tumbling through the dark. Now, imagine three lumps joined at the neck, like a cosmic string of pearls, and a tiny moon keeping pace alongside.

0:18 Speaker 2: That's a real object out in the Main Belt, and until this week, nobody knew it looked like that. We'll take you there first.

0:26 Speaker 1: And then we'll chase a wind, one that lights up our own sky, and the same kind of wind that's slowly stripping a planet.

0:35 Speaker 2: Baar. Goodday, and welcome to Astronomy Daily. It's Friday, the thirty first of July twenty twenty six.

0:43 Speaker 1: I'm Avery and I'm anna four stories today, a SkyWatch that spans both hemispheres, and a thread running right through the back half of the show. Avery, Where do we start?

0:55 Speaker 2: Where else with the three faced asteroid?

0:59 Speaker 1: So asteroid forty four NISA. The number tells you it was one of the early finds discovered back in eighteen fifty seven, one of the brightest asteroids in the whole Main Belt. That broad river of rubble between Mars and Jupiter. It's about seventy five kilometers across at its widest, so a serious chunk of rock, one of the largest of its particular type. Its type matters here. NISA is what astronomers call an E type. Its surface is rich in a pale mineral called instatite, which makes it unusually bright and reflective.

1:40 Speaker 1: There aren't many big E types, so NISA has always been a bit of a favorite, but its shape has been a nagging mystery for years. Earlier observations hinted it might be what's called a contact binary, two lobes stuck together a bit like a peanut or a snowman. We've seen plenty of those. Commet sixty seven P that Rosetta visited, the little asteroid dimorphous that the NASA Dart mission crashed into last year. Donald Johansson that the Lucy spacecraft flew past last year. Two lobes is almost normal.

2:18 Speaker 1: BISA isn't normal. A team led by Kate Minker at Lowell Observatory has just announced, in a study with the wonderful title Unmasking forty four Nissa, that NISA appears to have three lobes, three joined by two narrow necks, like a figure carved with two deep wastes around it. If it holds up it's the first trilobed asteroid ever seen.

2:46 Speaker 2: Three lobes. How do you even see that? These things are tiny dots even in big telescopes.

2:52 Speaker 1: That's the clever part. They used two of the sharpest eyes on Earth, the large binocular telescope in Arizona. Its main mirror is about eight meters roughly three times the size of Hubbles, running an instrument called shark Vis, plus the very large telescope down in Chile. And they used adaptive optics, a mirror that flexes hundreds of times a second, nearly six hundred tiny actuators pushing on it to cancel out the blurring of our atmosphere in real time. The result is sharper than Hubble. They imaged Nissa on two nights, the fifteenth of February and the twenty first of March this year, and both times the same strange three part silhouette turned up, which brings us to the second surprise.

3:42 Speaker 1: Nisa has a moon, a little one about a kilometer across, orbiting at least one hundred and seventy kilometers out. It's been given the placeholder name s Slash twenty twenty six dash forty four to one and it was hiding in plain sight, drowned out by the glare of the much brighter asteroid next to it. To dig it out, the team borrowed a trick from a completely different corner of astronomy, high contrast imaging, the same family of techniques we use to pull a faint planet out of the glare of its star.

4:18 Speaker 1: As one of the shark vis scientists gian Luca Lee Couci put it, they used that technique to catch a faint companion whose light was being swamped by the primary And because they caught it moving across two separate observing runs, they know it's genuinely in orbit, not a background star photo bombing the shot and a.

4:40 Speaker 2: Moon is useful, right, not just a bonus.

4:43 Speaker 1: It's enormously useful. This is the thing I love about it. Watch how fast the moon goes round and how far out it sits, And you can weigh the asteroid. You get Nice's mass. Combine the mass with the size, and you get its density. Density is the whole ballgame here, because there are two competing stories for what NYSA actually is. Story one, it's a genuine three part body, maybe a contact trinary three chunks that drifted together and gently stuck. Story two. It's one solid, deeply dented lump that only looks three lobed from our angle.

5:24 Speaker 1: Density can help tell those apart. A loose rubble pile reads light and fluffy, a solid coherent rock reads dense. So that little moon is going to help settle what kind of world this is and how it got so weird.

5:41 Speaker 2: Any theories on the how nothing.

5:43 Speaker 1: Locked in, and that honesty is the fun of it. It could be a record of gentle, slow motion collisions in the belt, bodies bumping and merging over billions of years. It could be the aftermath of a bigger smash that left a battered star, or observations of that moon will narrow it down. For now, we've got a brand new kind of object, a triple lobed asteroid with its own satellite, sitting in a part of the sky we thought we understood, And that's the quiet lesson of Nisa. It was found in eighteen fifty seven.

6:20 Speaker 1: It's one of the best studied bright asteroids we have, and in twenty twenty six its skill had two secrets, left a shape nobody expected and a moon nobody had seen. The solar system is not done surprising us.

6:35 Speaker 2: From a world we can nearly touch to one we may never reach, but might one day actually see. NASA has just backed the genuinely audacious idea, a plan to photograph the surface of a planet around another star, not detect it, not measure it, see it, continents, oceans, weather.

6:56 Speaker 1: Hang on, we can't do that. I feel like we have pictures of exoplanets.

7:02 Speaker 2: We have dots. Every exoplanet we've ever found is in a sense invisible. We infer it from a star's tiny wobble or a faint dip in brightness as the planet crosses in front. In the very best cases, we've captured a single pixel of light. Nobody has ever resolved a surface. The problem is brutal. A star can be around ten billion times brighter than the little Earth sized planet beside it, and the two sit almost on top of each other in the sky. The new concept comes from physicist Paul Stankis at Brookhaven, and it's one of eighteen early stage ideas NASA just funded through its Innovative Advanced Concepts Program NIAK.

7:41 Speaker 2: These are seed grants, small money, nine months permission to chase something wild. This is called mapping alien continents. It works in two moves, first a new kind of light canceling instrument, another that blots out the star's glare while keeping the planet's light at a contrast of ten billion to one, or be better then the really bold bit. You fly two of these on separate spacecraft about one hundred kilometers apart, and combine their beams. Will they act as one enormous telescope, big enough in principle to resolve features on the planet's face.

8:14 Speaker 1: A telescope one hundred kilometers wide made of two spacecraft flying information.

8:20 Speaker 2: That's a dream, and I want to be honest about where this sits. It's a concept study, not a mission on a launch pad. It may never fly in this form, but this is exactly how the big leaps begin. Someone asks what if we could actually look, and NASA hands them a little funding to find out whether the physics holds. If it ever came together, it would turn exoplanets from statistics into places. Now, Anna, speaking of things we can see from ray, here.

8:47 Speaker 1: We've got weather coming in space. Weather forecasters at NOAH are tracking a couple of clouds of solar material heading our way. Coronal mass ejections big blobs of charged as flung off the Sun. Bees too, are faint, and they're only likely to give Earth a glancing blow over the next day or so.

9:08 Speaker 2: Glancing, but not nothing.

9:10 Speaker 1: Not nothing. Layer those CMEs on top of a fast stream already flowing from a coronal hole, a gap in the Sun's outer atmosphere, and the models suggest we could tip into a g one storm. That's the mildest rung on the scale, no drama for the power grid, but enough to nudge the aurora to slightly lower latitudes than usual, though over the coming nights. It's worth a look if you're up high, and I'll give you the where and when in the SkyWatch here's the thread. Though, that same solar wind, the constant outflow from the Sun is gentle at Earth because we've got a strong magnetic field and a thick atmosphere shrugging it off.

9:52 Speaker 1: Auroras are the pretty side of that shrug. But not every world is so lucky. Some planets have been standing in that wind for billions of years with no shield at all.

10:04 Speaker 2: Which is the perfect cue for my next one me escapade. A pair of nasascraft nicknamed Blue and Gold after the University of California, Berkeley colors built by rocket Lab and launched last November on a blue origin New Glen. Their Mars bound, and right now they're loitering out near spot called L two, about a million miles beyond Earth, waiting for the road to Mars to open. While they wait, one of them turned its cameras back toward home and snap the family portrait Earth and the Moon together as two slim crescents.

10:38 Speaker 2: In ordinary visible light, they look exactly as you'd hope, two bright sunlit sickles against the black. But these cameras also see in thermal infrared heat, and that view is stranger and honestly a bit beautiful. The night side of Earth glows softly with its own warmth, while the Moon's dark half sits far far cold. A portrait in light and a portrait and heat of the same two worlds gorgeous.

11:05 Speaker 1: But that's not why they built it, is it?

11:08 Speaker 2: It's not?

11:09 Speaker 3: And here's where our Threadlands Escapade exists to study exactly what we were just talking about. Its whole job once it reaches Mars in twenty twenty seven is to measure how the solder wind strips away the Martian atmosphere. Mars doesn't have a global magnetic shield like ours, so the same wind that just gives us Auroras has over billions of years helped peel Mars from a warmer, wetter world into the thin, cold desert we see today, two spacecraft taking readings from two vantage points at once, watching a planet lose its air in real time.

11:41 Speaker 3: That Earth and Moon portrait was really a calibration check, a chance to point the cameras at familiar targets before the main event, but it doubles as a quiet reminder. A shielded world and an unshielded one are separated by not very much at all.

11:57 Speaker 1: The wind that paints our sky and the wind that scours Mars same sun, lovely thread avery right out under the sky. First, the moon. We've just come off the full buck Moon on the twenty ninth, so we're in a bright waning giveus stretch. Beautiful to look at, but that glare will wash out anything faint for the next several nights. Worth knowing before you plan Betiers. The Southern Delta Aquariids and the Alpha Capricornids have just passed their peak on the thirtieth into the thirty first. From here in the southern hemisphere, the delta aquariods still favor us, but with the moon this bright, keep expectations modest and watch for the occasional slow, bright capricorned fireball, which both hemispheres can catch.

12:46 Speaker 1: The better news is what's coming. The perseods build to their peak on the night of the twelfth into the thirteenth of August, and this year the moon is nearly new, so it's a genuinely dark, generous window for North America. That's prime. Find a dark spot. Look up after midnight, and the northern sky can deliver a meteor a minute at its best. From the southern hemisphere, the perseods sit low in the north, so you'll see fewer, but a clear northern horizon is worth a try. Mark the twelfth. Also on the twelfth of August, a total solar eclipse.

13:23 Speaker 1: The path of totality runs across Greenland, Iceland, and a slice of Spain, with partial phases for parts of northern North America and Europe if you're anywhere near it. Never look at the partial sun without certified eclipse glasses that meet the ISO one two three one two DASH two standard ordinary sunglasses will not protect your eyes. Totality only is safe to view with the naked eye, and only for those precious seconds it lasts. Planets quickly both hemispheres. The pre dawn sky is the place to be, with the bright planets gathering low in the east before sunrise.

14:03 Speaker 1: From Sydney, look to the eastern horizon in the hour before dawn from North America, this same window an hour or so before your local sunrise. One quick diary item, and this one's for our telescope owners. On the fifth of August, a dead SpaceX Falcon nine upper stage space junk we tracked since it launched Firefly's Blue Ghost lander back in January of last year is expected to smack into the Moon near Einstein Crater at about half past six Universal time for North America. That's the small hours of the fifth, and you're the best placed to try for it.

14:42 Speaker 1: Aim for the faint dust plume near the Moon's eastern edge. Not a naked eye flash. You'll want a decent telescope From Sydney, the Moon isn't up at impact, so down here we'll be leaning on the after images from orbiters like NASA's Lunar Reconnaissance orbiter and to close our thread, the aurora. If those solar storms land is forecast, watch the high latitudes over the coming nights across the northern tier of the United States and up into Canada in the north and down towards Tasmania, southern New Zealand and southern Victoria in the south.

15:19 Speaker 1: Same sun, same wind, both ends of the Earth, and if you catch a glow, you'll know exactly what you're looking at.

15:26 Speaker 2: Everything we talked about today, the links, the images of Nysa and that Earth and Moon portrait is at Astronomy Daily dot io, along with the daily newsfeed and the newsletter. Sign up and.

15:38 Speaker 1: If you spotted an aurora or bagged a persead tell us. There's a listener contact form on the site and we love hearing what you've seen.

15:46 Speaker 2: That's Astronomy Daily for Friday, the thirty first of July. I'm avery and I'm anna until next time.

15:53 Speaker 1: Clear Skies, Sunday.

15:57 Speaker 2: Stars. Star is the Soul. Star is the Soul