Humanity Just Moved an Asteroid's Orbit Around the Sun

0:00 Speaker 1: You're listening to Astronomy Daily.

0:02 Speaker 2: I'm Anna and I'm Avery. It is Saturday, the seventh

0:06 Speaker 2: of March twenty twenty six, and as usual, we have

0:09 Speaker 2: a packed show for you today.

0:11 Speaker 1: We absolutely do. Here's a question to get you thinking.

0:15 Speaker 1: Back in September twenty twenty two, NASA slammed a spacecraft

0:19 Speaker 1: into an asteroid. You probably remember that, but did you

0:23 Speaker 1: know that we only just confirmed something remarkable. That impact

0:28 Speaker 1: didn't just nudge the asteroid, It actually changed the orbit

0:32 Speaker 1: of an entire asteroid system around the Sun.

0:36 Speaker 2: For the first time in human history, we move the

0:39 Speaker 2: celestial body's solar orbit. And that's just story one. We've

0:43 Speaker 2: also got gravitational waves, a spacecraft emergency, an orbit, a

0:48 Speaker 2: forty five year old theory biting the dust, our young

0:51 Speaker 2: Sun blowing its very first cosmic bubble, and the gorgeous

0:55 Speaker 2: double planet show. Intonight, sky, let's go.

0:58 Speaker 1: So let's kick off with the dark story, and I

1:01 Speaker 1: think it deserves a moment to really sync in. We

1:04 Speaker 1: already knew that Dart was a success. We knew it

1:07 Speaker 1: shortened the orbit of dimorphous around its partner asteroid Ditamos

1:11 Speaker 1: by about thirty three minutes. That was confirmed back in

1:14 Speaker 1: twenty twenty two, but a new study published yesterday in

1:17 Speaker 1: the journal Science Advances has revealed something even bigger.

1:22 Speaker 2: Right, because ditamos and dimorphous are gravitationally linked, they moved together,

1:28 Speaker 2: and researchers have now confirmed that the debris blasted off

1:31 Speaker 2: Dimorphous during that impact was so enormous We're talking over

1:36 Speaker 2: a million kilograms of rock and dust, that it gave

1:39 Speaker 2: the whole binary system an extra kick.

1:42 Speaker 1: And that extra kick was measurable. The orbital period of

1:46 Speaker 1: the entire Ditamo system around the Sun shortened by zero

1:50 Speaker 1: point one point five seconds. Now, I know that sounds tiny,

1:54 Speaker 1: but this is the first time a human made object

1:57 Speaker 1: has measurably changed the path of a celestial body around

2:01 Speaker 1: our star.

2:02 Speaker 2: To even measure that, the team had to get incredibly creative.

2:06 Speaker 2: They tracked what are called stellar occultations, moments when the

2:10 Speaker 2: asteroid passes in front of a background star and briefly

2:14 Speaker 2: blocks its light. Volunteers around the world contributed twenty two

2:18 Speaker 2: of these observations between October twenty twenty two and March

2:22 Speaker 2: twenty twenty five. Twenty two pinpoint moments of a star

2:27 Speaker 2: blinking out and from those They derived the change of

2:30 Speaker 2: zero point fifteen seconds in a seven hundred seventy day

2:34 Speaker 2: solar orbit.

2:35 Speaker 1: The momentum enhancement factor turned out to be about two,

2:39 Speaker 1: meaning the debris ejected by the impact roughly doubled the

2:43 Speaker 1: total push given to the asteroid. Dart didn't just hit dimorphos,

2:48 Speaker 1: it turned a dimorphous into a rocket, and.

2:51 Speaker 2: Thomas Statler, leads Sciences for Solar System Small Bodies at

2:55 Speaker 2: NASA Headquarters, framed it perfectly. He said, a tiny change can,

3:00 Speaker 2: and given enough time, grow into a significant deflection. This

3:04 Speaker 2: result validates kinetic impact as a genuine planetary defense technique,

3:09 Speaker 2: not just for nudging a moon, but for altering the

3:11 Speaker 2: path of an entire binary system around the Sun.

3:15 Speaker 1: Lisas harrispacecraft, which launched in twenty twenty four, is expected

3:19 Speaker 1: to arrive at the Ditamo system later this year to

3:22 Speaker 1: study the aftermath of close, though the science from this

3:25 Speaker 1: impact is very much still unfolding.

3:28 Speaker 2: Story two and it is a landmark one. The LGO

3:33 Speaker 2: Virgocagra collaboration the LVK has just published the fourth edition

3:39 Speaker 2: of the Gravitational Wave Transient Catalog known as GWTC four,

3:44 Speaker 2: and the headline they've more than doubled the total number

3:48 Speaker 2: of gravitational wave detections ever made.

3:51 Speaker 1: Before this release, the entire catalog contained ninety candidates from

3:55 Speaker 1: three previous observing runs stretching back to twenty fifteen. New

4:00 Speaker 1: catalog adds one hundred and twenty eight new events, all

4:03 Speaker 1: detected during just the first nine months of the fourth

4:06 Speaker 1: observing run between May twenty twenty three and January twenty

4:10 Speaker 1: twenty four.

4:11 Speaker 2: So we've gone from ninety to two hundred and eighteen

4:15 Speaker 2: in one update. And it's not just the quantity that's exciting,

4:19 Speaker 2: it's the variety. The catalog includes the heaviest black hole

4:23 Speaker 2: binary merger ever detected, with each black hole weighing in

4:26 Speaker 2: at around one hundred and thirty times the mass of

4:29 Speaker 2: our Sun.

4:30 Speaker 1: There's also a binary where both black holes are spinning

4:33 Speaker 1: at roughly forty percent the speed of light, and there

4:36 Speaker 1: are two new mixed mergers, a black hole colliding with

4:39 Speaker 1: a neutron star. Each one of those is a treasure

4:42 Speaker 1: trove for astrophysics.

4:44 Speaker 2: Daniel Williams, a researcher at the University of Glasgow and

4:47 Speaker 2: LVK member, put it well. He said they're pushing into

4:51 Speaker 2: new parts of parameter space, seeing things that are more massive,

4:55 Speaker 2: spinning faster, and more astrophysically unusual than anything detect before.

5:01 Speaker 1: What I love about this is what it means for

5:03 Speaker 1: testing Einstein. The catalog includes an event with one of

5:06 Speaker 1: the loudest gravitational wave signals ever recorded GW two three

5:11 Speaker 1: zero eight one four, and the team used it to

5:14 Speaker 1: run precision tests of general relativity. It passed with flying colors,

5:19 Speaker 1: but the fact that we're now running those tests on

5:21 Speaker 1: events this extreme is remarkable.

5:24 Speaker 2: Bigro and its partners are currently in a maintenance break,

5:27 Speaker 2: but a new six month observing run is expected to

5:30 Speaker 2: begin in late twenty twenty six. Given how rapidly the

5:34 Speaker 2: catalog is growing, that run could double it again.

5:38 Speaker 1: All right, story three, and this one has a genuine

5:40 Speaker 1: element of suspense. Europe's Proba three mission is in trouble.

5:45 Speaker 1: Issa confirmed yesterday that they have lost contact with one

5:48 Speaker 1: of the two spacecraft that make up the Proba three mission.

5:52 Speaker 2: Let me explain what Proba three actually is, because it's

5:55 Speaker 2: a fascinating concept. It launched from India back in December

5:59 Speaker 2: twenty two, twenty four, and it consists of two separate

6:02 Speaker 2: spacecraft designed to fly in extraordinarily precise formation about one

6:07 Speaker 2: hundred and fifty meters apart. To create artificial solar eclipses

6:11 Speaker 2: in space.

6:12 Speaker 1: One spacecraft, the occult, physically blocks the bright face of

6:17 Speaker 1: the Sun. The other, the coronagraph, uses that shadow to

6:20 Speaker 1: image the Sun's faint outer atmosphere, the corona, without being

6:25 Speaker 1: blinded by the solar disc. And to make this work,

6:28 Speaker 1: the two spacecraft must maintain alignment to within millimeter accuracy.

6:33 Speaker 2: It's an almost absurdly precise operation, and it was working.

6:37 Speaker 2: In May of last year. The spacecraft achieved their landmark

6:41 Speaker 2: formation flying test. In June, they captured the first ever

6:45 Speaker 2: images of an artificial solar eclipse in space. It was

6:48 Speaker 2: a genuine technological first.

6:51 Speaker 1: And then on the weekend of February fourteenth, something went wrong.

6:56 Speaker 1: The CORONAFT spacecraft, the one doing the imaging experience hinst

7:00 Speaker 1: an anomaly that prevented it from entering safe mode. Issa

7:03 Speaker 1: describes it as a progressive loss of attitude. In other words,

7:07 Speaker 1: the spacecraft slowly lost its orientation.

7:10 Speaker 2: As it drifted. Its solar panels moved away from the Sun,

7:14 Speaker 2: the batteries drained, the spacecraft dropped into survival mode and

7:18 Speaker 2: contact was lost. ESA says root cause is under investigation,

7:23 Speaker 2: and they're exploring whether the companion occult or spacecraft can

7:26 Speaker 2: be maneuvered closer to assist in recovery.

7:29 Speaker 1: Losing either spacecraft would effectively end the probe of three mission.

7:34 Speaker 1: ESA says teams are working hard and they will provide

7:36 Speaker 1: updates as new information becomes available. This is very much

7:40 Speaker 1: a developing story. We'll keep following it.

7:43 Speaker 2: Story four is a classic example of a long held

7:46 Speaker 2: scientific belief getting overturned. For forty five years, astronomers thought

7:51 Speaker 2: they understood how stars like our Sun change as they age,

7:55 Speaker 2: specifically how their rotation pattern evolved.

7:59 Speaker 1: The idea this our Sun rotates differentially. The equator takes

8:04 Speaker 1: about twenty five days to complete one full rotation, while

8:07 Speaker 1: the poles take about thirty five days. Equator faster, poles slower.

8:12 Speaker 1: That's called solar type differential rotation, and scientists believed that

8:16 Speaker 1: as stars slowed down over billions of years, they would

8:20 Speaker 1: eventually flip the poles would start spinning faster than the

8:23 Speaker 1: equator instead.

8:25 Speaker 2: That flip state was called antisolar differential rotation. Theoretical simulations

8:31 Speaker 2: predicted it. No one had ever observed it, but the

8:34 Speaker 2: model said it should happen, and for decades the lack

8:37 Speaker 2: of observations was attributed to limitations in our telescope technology.

8:41 Speaker 1: But now researchers at Nagoya University in Japan have used Fugaku,

8:47 Speaker 1: the country's most powerful supercomputer, to run the most detailed

8:52 Speaker 1: simulations ever of stellar interiors, and the result is clear.

8:57 Speaker 1: The flip doesn't happen.

9:00 Speaker 2: Key was resolution. Previous simulations were low resolution, and magnetic

9:05 Speaker 2: fields faded out of the models entirely. At high resolution,

9:09 Speaker 2: we're talking five point four billion grid points per simulated star,

9:14 Speaker 2: the magnetic field stayed strong, and those magnetic fields, it

9:17 Speaker 2: turns out, are what prevent the rotation from flipping.

9:21 Speaker 1: Professor Heidiyuki Haata, one of the co authors, set it simply,

9:26 Speaker 1: turbulence and magnetism keep the equator spinning faster than the

9:30 Speaker 1: poles throughout the star's life. The switch doesn't happen because

9:34 Speaker 1: magnetic fields, which previous simulations missed, prevent it.

9:38 Speaker 2: And there's a bonus finding magnetic fields in solar type

9:42 Speaker 2: stars weaken continuously throughout their lifetime with no revival In

9:47 Speaker 2: old age, previous models had predicted a magnetic comeback that

9:51 Speaker 2: doesn't happen either.

9:53 Speaker 1: This matters practically too. A corrected model of stellar rotation

9:57 Speaker 1: helps us better understand the Sun's eleven year sunspot cycle

10:02 Speaker 1: and could improve our predictions of how magnetic activity affects

10:06 Speaker 1: the habitability of planets orbiting Sun like stars over billions

10:10 Speaker 1: of years.

10:11 Speaker 2: Dory five and it's a lovely one. A real window

10:15 Speaker 2: into our own Sun's distant past. NASA's Chandra X ray

10:19 Speaker 2: observatory has captured the very first image of what's called

10:23 Speaker 2: an astrosphere around the sun like star.

10:27 Speaker 1: Our Sun has a protective bubble around it, called the heliosphere,

10:31 Speaker 1: created by the solar wind streaming outward and carving out

10:34 Speaker 1: a cavity in interstellar space. It's enormous. It extends far

10:39 Speaker 1: beyond the outer planets and shields the Solar System from

10:43 Speaker 1: harmful galactic cosmic rays, but we've never been able to

10:46 Speaker 1: photograph it from the outside.

10:48 Speaker 2: The star Chandra observed is called HD sixty one zero

10:53 Speaker 2: zero five, and it sits about one hundred and twenty

10:56 Speaker 2: light years away in the constellation Pupis. It has roughly

11:00 Speaker 2: the same mass and temperature as our Sun, but it's

11:03 Speaker 2: only about one hundred million years old. Our Sun is

11:07 Speaker 2: around five billion years old, so HD six one zero

11:11 Speaker 2: zero five is cosmically speaking a baby, and because.

11:15 Speaker 1: It's so young, its stellar wind is dramatically more powerful.

11:19 Speaker 1: It blows about three times faster, and it's twenty five

11:23 Speaker 1: times denser than the wind from our Sun today. That's

11:26 Speaker 1: why its astrosphere is bright enough to detect an X rays.

11:30 Speaker 1: The powerful wind collides with the surrounding interstellar dust and gas,

11:35 Speaker 1: and that collision produces X ray emission that Chandra can detect.

11:40 Speaker 2: The astrosphere has a diameter roughly two hundred times the

11:43 Speaker 2: distance between Earth and the Sun. Carry Lists of Johns

11:47 Speaker 2: Hopkins University, who led the study, put it beautifully, We've

11:51 Speaker 2: been studying our Son's heliosphere for decades, but we can

11:55 Speaker 2: never see it from the outside. This is the closest

11:58 Speaker 2: thing we have to a photograph of what our own

12:00 Speaker 2: Sun's bubble look like several billion years ago.

12:04 Speaker 1: The star is also nicknamed the Moth because a surrounding

12:08 Speaker 1: disc of dust forms a mothlike structure around it, and interestingly,

12:12 Speaker 1: the dense dusty environment is actually part of why the

12:16 Speaker 1: astrosphere is so visible here, making HD six one zero

12:20 Speaker 1: zero five a uniquely ideal subject for this kind of observation.

12:25 Speaker 2: And we'll finish with some skywatching news because tonight and

12:29 Speaker 2: tomorrow night offer something quite special. Venus and Saturn are

12:33 Speaker 2: meeting up in the evening sky, and it's a treat

12:36 Speaker 2: for anyone who can get outside shortly after sunset.

12:39 Speaker 1: Venus is already impossible to miss right now. It's shining

12:43 Speaker 1: at magnitude minus three point nine, which makes it by

12:46 Speaker 1: far the brightest object in the sky after the Sun

12:49 Speaker 1: and moon. Tonight and tomorrow, Saturn sits close alongside it,

12:54 Speaker 1: though considerably fainter at magnitude one point zero.

12:57 Speaker 2: The best time to look is about thirty minutes after sunset,

13:01 Speaker 2: when Venus will be roughly seven degrees above the western horizon.

13:05 Speaker 2: Binoculars will help a lot. Saturn should pop into view

13:08 Speaker 2: easily near brilliant Venus. You'll have about seventy minutes before

13:12 Speaker 2: both planets set, and.

13:14 Speaker 1: If you're pointing a telescope at Venus tonight, you're in

13:17 Speaker 1: for an extra treat. The planet is currently showing a

13:20 Speaker 1: ninety seven percent lit disc, almost fully illuminated from our perspective.

13:25 Speaker 1: It's a gorgeous site. Neptune is also lurking nearby, just

13:29 Speaker 1: over a degree from Saturn, though you'll need a telescope

13:32 Speaker 1: to catch that one.

13:34 Speaker 2: So get outside this evening. If skies are clear, Venus

13:38 Speaker 2: is your guide. Find that brilliant white beacon low in

13:41 Speaker 2: the west, and Saturn will be right there waiting for you.

13:45 Speaker 1: And that's our show for today. Six stories from an

13:48 Speaker 1: asteroid nudged around the Sun to a planet pairing up

13:51 Speaker 1: Intonight's sky. It's a great time to be paying attention

13:55 Speaker 1: to the universe.

13:56 Speaker 2: If you enjoyed today's episode, please subscribe wherever you're listening

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14:05 Speaker 1: You can find us at Astronomy Daily dot io for

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14:16 Speaker 1: keep looking up clear skies, everyone.

14:19 Speaker 2: Sunday Starsz Starz