Artemis II : Go for Launch — Plus Saturn’s Rings, The Gigamaser & A Star From The Dawn of Time

WEBVTT
Kind: captions
Language: en

00:00:00.240 --> 00:00:03.030
Hello and welcome to Astronomy Daily.


00:00:03.040 --> 00:00:04.150
I'm Anna.


00:00:04.160 --> 00:00:06.150
>> And I'm Avery. And if you're listening


00:00:06.160 --> 00:00:08.230
to this on the morning of Wednesday, the


00:00:08.240 --> 00:00:10.709
1st of April here in Australia, there is


00:00:10.719 --> 00:00:13.430
a rocket on a launchpad in Florida right


00:00:13.440 --> 00:00:16.550
now, fully fueled, fully crewed, and


00:00:16.560 --> 00:00:18.390
pointed at the moon.


00:00:18.400 --> 00:00:21.510
>> This is not an April Fool's joke.


00:00:21.520 --> 00:00:24.070
>> Absolutely not. For the first time in


00:00:24.080 --> 00:00:26.630
over 50 years, human beings are


00:00:26.640 --> 00:00:29.029
preparing to leave Earth and head toward


00:00:29.039 --> 00:00:31.910
the moon. And today on this very special


00:00:31.920 --> 00:00:35.430
episode 77 of season 5, we are your


00:00:35.440 --> 00:00:38.150
countdown companion. We have six stories


00:00:38.160 --> 00:00:41.190
for you today. And yes, Artemis 2 is


00:00:41.200 --> 00:00:43.670
front and center. But we've also got a


00:00:43.680 --> 00:00:46.470
record-breaking space laser, a 12


00:00:46.480 --> 00:00:49.190
billionyear-old comet, a star born from


00:00:49.200 --> 00:00:51.910
the ashes of the very first stars in the


00:00:51.920 --> 00:00:54.229
universe, and a new chapter in the


00:00:54.239 --> 00:00:56.310
mystery of Saturn's rings.


00:00:56.320 --> 00:00:58.389
>> It is without question one of the most


00:00:58.399 --> 00:01:00.389
extraordinary days in the history of


00:01:00.399 --> 00:01:02.950
human space flight. Let's go.


00:01:02.960 --> 00:01:05.270
>> We begin where the world's attention is


00:01:05.280 --> 00:01:07.670
today. Kennedy Space Center, Cape


00:01:07.680 --> 00:01:09.830
Canaveral, Florida, where the countdown


00:01:09.840 --> 00:01:12.550
clock for NASA's Aremis 2 mission is


00:01:12.560 --> 00:01:13.350
ticking.


00:01:13.360 --> 00:01:16.230
>> At 4:44 p.m. Eastern time yesterday,


00:01:16.240 --> 00:01:17.830
that's early this morning for our


00:01:17.840 --> 00:01:19.990
Australian listeners. NASA flight


00:01:20.000 --> 00:01:21.510
controllers started the official


00:01:21.520 --> 00:01:25.109
countdown. Liftoff is targeted at 6:24


00:01:25.119 --> 00:01:27.830
p.m. Eastern, which is 8:24 tomorrow


00:01:27.840 --> 00:01:30.710
morning, AEDT. The crew has been in


00:01:30.720 --> 00:01:32.789
quarantine at the Neil Armstrong


00:01:32.799 --> 00:01:34.870
operations and checkout building


00:01:34.880 --> 00:01:37.190
following a strict schedule of sleep,


00:01:37.200 --> 00:01:39.590
nutrition, and technical briefings.


00:01:39.600 --> 00:01:41.990
Commander Reed Wiseman told reporters on


00:01:42.000 --> 00:01:44.550
the weekend, and I love this quote,


00:01:44.560 --> 00:01:46.630
"Hey, let's go to the moon."


00:01:46.640 --> 00:01:49.109
>> That is the energy we need. Wisemen


00:01:49.119 --> 00:01:51.429
leads a crew of four. Commander Reed


00:01:51.439 --> 00:01:54.310
Wisman, pilot Victor Glover, mission


00:01:54.320 --> 00:01:56.550
specialist Christina Coch, and Canadian


00:01:56.560 --> 00:01:59.270
astronaut Jeremy Hansen. Together, they


00:01:59.280 --> 00:02:01.270
will become the first humans to travel


00:02:01.280 --> 00:02:03.670
to the vicinity of the moon since Apollo


00:02:03.680 --> 00:02:06.950
17 in December 1972.


00:02:06.960 --> 00:02:10.070
>> More than 53 years. And this mission,


00:02:10.080 --> 00:02:13.110
Artemis 2, won't land on the moon. It's


00:02:13.120 --> 00:02:16.150
a 10-day test flight. The Orion capsule


00:02:16.160 --> 00:02:18.470
launched aboard the massive space launch


00:02:18.480 --> 00:02:21.190
system rocket will perform a figure 8


00:02:21.200 --> 00:02:23.750
trajectory out around the moon coming


00:02:23.760 --> 00:02:26.390
within about 6,000 m of the lunar


00:02:26.400 --> 00:02:29.430
surface on April 6th, then back to Earth


00:02:29.440 --> 00:02:31.510
for splashdown in the Pacific on


00:02:31.520 --> 00:02:33.589
approximately April 11th.


00:02:33.599 --> 00:02:35.990
>> The purpose is to stress test the Orion


00:02:36.000 --> 00:02:37.910
capsule's life support systems with


00:02:37.920 --> 00:02:40.229
humans on board for the first time.


00:02:40.239 --> 00:02:42.309
Everything they learn paves the way for


00:02:42.319 --> 00:02:45.190
Artemis 3, now planned as a low Earth


00:02:45.200 --> 00:02:48.150
orbit docking test in 2027 and


00:02:48.160 --> 00:02:50.390
ultimately the first lunar landing since


00:02:50.400 --> 00:02:53.030
Apollo in 2028.


00:02:53.040 --> 00:02:55.430
>> NASA launch director Charlie Blackwell


00:02:55.440 --> 00:02:57.509
Thompson reported yesterday that the


00:02:57.519 --> 00:03:00.550
countdown runup has been quote extremely


00:03:00.560 --> 00:03:03.030
smooth with only very minor ground


00:03:03.040 --> 00:03:05.430
equipment issues. Weather is currently


00:03:05.440 --> 00:03:08.550
forecast at 80% favorable. Some cloud


00:03:08.560 --> 00:03:10.710
cover and potential high winds on the


00:03:10.720 --> 00:03:12.869
ground are the primary concerns.


00:03:12.879 --> 00:03:15.190
>> And NASA has confirmed there's a 6-day


00:03:15.200 --> 00:03:17.350
launch window from April 1st through


00:03:17.360 --> 00:03:19.589
April 6th before the next opportunity


00:03:19.599 --> 00:03:21.270
opens at the end of the month. So,


00:03:21.280 --> 00:03:22.710
there's some flexibility if they need


00:03:22.720 --> 00:03:23.270
it.


00:03:23.280 --> 00:03:25.589
>> For our Southern Hemisphere listeners,


00:03:25.599 --> 00:03:28.309
and this is genuinely moving, this is


00:03:28.319 --> 00:03:30.470
the moment our generation has been


00:03:30.480 --> 00:03:33.270
waiting for. The next chapter of human


00:03:33.280 --> 00:03:35.670
exploration of the cosmos begins


00:03:35.680 --> 00:03:39.910
Thursday morning, April 2nd at 9:24 a.m.


00:03:39.920 --> 00:03:42.470
Australian Eastern time. And if in the


00:03:42.480 --> 00:03:46.710
US, 6:24 p.m. Eastern Daylight Time on


00:03:46.720 --> 00:03:51.110
April 1st, which all translates to 22:24


00:03:51.120 --> 00:03:55.110
UTC on April 2nd. I hope I got all those


00:03:55.120 --> 00:03:56.390
conversions right.


00:03:56.400 --> 00:03:59.589
>> We will be watching every second. Now,


00:03:59.599 --> 00:04:01.429
there was a dramatic subplot to


00:04:01.439 --> 00:04:03.990
yesterday's launch preparations. The sun


00:04:04.000 --> 00:04:06.309
decided to get involved. On Sunday


00:04:06.319 --> 00:04:10.630
night, a massive X1.4 class solar flare


00:04:10.640 --> 00:04:13.030
erupted from an active sunspot region


00:04:13.040 --> 00:04:16.469
designated AR4405.


00:04:16.479 --> 00:04:19.030
It peaked at just after 11:00 p.m.


00:04:19.040 --> 00:04:21.430
Eastern time and triggered a significant


00:04:21.440 --> 00:04:24.070
highfrequency radio blackout across the


00:04:24.080 --> 00:04:26.870
sunlit side of Earth, including, as it


00:04:26.880 --> 00:04:29.350
happens, parts of Southeast Asia and


00:04:29.360 --> 00:04:31.030
Northern Australia.


00:04:31.040 --> 00:04:33.189
>> Class flares are the most powerful


00:04:33.199 --> 00:04:36.950
category the sun produces. An X1.4 is


00:04:36.960 --> 00:04:39.189
serious business. The flare also


00:04:39.199 --> 00:04:41.749
launched a coronal mass ejection, a


00:04:41.759 --> 00:04:44.310
massive cloud of solar plasma with a


00:04:44.320 --> 00:04:46.629
possible earthdirected component.


00:04:46.639 --> 00:04:49.030
>> So NASA had something of an anxious


00:04:49.040 --> 00:04:51.909
Monday morning, but at the Lminus2 press


00:04:51.919 --> 00:04:54.150
conference, associate administrator Amit


00:04:54.160 --> 00:04:56.950
Cashatria gave everyone the all clear.


00:04:56.960 --> 00:04:59.510
Quote, we're not expecting the CME to


00:04:59.520 --> 00:05:01.830
cause any effects. We're not tracking


00:05:01.840 --> 00:05:03.990
concerns for the mission in general.


00:05:04.000 --> 00:05:07.830
Artemis 2 is go for April 1st. DOA's


00:05:07.840 --> 00:05:09.749
space weather prediction center has


00:05:09.759 --> 00:05:12.390
issued a G2, that's moderate,


00:05:12.400 --> 00:05:14.950
geomagnetic storm watch for today,


00:05:14.960 --> 00:05:18.150
Tuesday, March 31st, with G1, minor


00:05:18.160 --> 00:05:20.310
storm conditions possible through launch


00:05:20.320 --> 00:05:21.430
day tomorrow.


00:05:21.440 --> 00:05:23.430
>> And here's the silver lining for our


00:05:23.440 --> 00:05:26.070
listeners. That geomagnetic activity


00:05:26.080 --> 00:05:28.469
means auroras could be visible at lower


00:05:28.479 --> 00:05:31.670
latitudes than usual tonight. Under G2


00:05:31.680 --> 00:05:33.590
conditions, the Southern Aurora, the


00:05:33.600 --> 00:05:36.550
Aurora Arralis, may be visible further


00:05:36.560 --> 00:05:38.870
north than normal. Southern Hemisphere


00:05:38.880 --> 00:05:41.430
aurora watchers get outside tonight.


00:05:41.440 --> 00:05:43.270
>> We'll be watching the skies and the


00:05:43.280 --> 00:05:45.350
launchpad at the same time.


00:05:45.360 --> 00:05:47.350
>> All right, now let's travel to the other


00:05:47.360 --> 00:05:49.270
end of the universe. Because while


00:05:49.280 --> 00:05:51.270
everyone's been watching the launchpad,


00:05:51.280 --> 00:05:53.029
astronomers have spotted something


00:05:53.039 --> 00:05:55.670
extraordinary in the deep cosmos.


00:05:55.680 --> 00:05:57.830
Scientists have discovered the most


00:05:57.840 --> 00:06:00.710
distant and most powerful natural space


00:06:00.720 --> 00:06:03.270
laser ever detected. And I know that


00:06:03.280 --> 00:06:05.270
sounds like science fiction, but these


00:06:05.280 --> 00:06:07.510
things are very much real. They're


00:06:07.520 --> 00:06:10.390
called, the microwave equivalent of a


00:06:10.400 --> 00:06:13.110
laser. Where a laser amplifies visible


00:06:13.120 --> 00:06:15.590
light, a mermpic


00:06:15.600 --> 00:06:18.230
radiation. When a mer is powerful enough


00:06:18.240 --> 00:06:20.710
to be seen in other galaxies, it gets


00:06:20.720 --> 00:06:23.670
the name megaer. And now astronomers


00:06:23.680 --> 00:06:25.749
have found something so powerful they're


00:06:25.759 --> 00:06:28.309
proposing an entirely new category.


00:06:28.319 --> 00:06:31.029
>> A gigamaser. The signal comes from a


00:06:31.039 --> 00:06:35.189
galaxy system designated deep breath h a


00:06:35.199 --> 00:06:41.670
t lsj42,935.3us


00:06:41.680 --> 00:06:44.150
2,836.


00:06:44.160 --> 00:06:46.790
Located approximately 8 billion


00:06:46.800 --> 00:06:49.189
lightyear from Earth. The light we're


00:06:49.199 --> 00:06:51.350
detecting began its journey when the


00:06:51.360 --> 00:06:53.670
universe was barely half its current


00:06:53.680 --> 00:06:54.469
age.


00:06:54.479 --> 00:06:56.710
>> It was discovered by the Mircat radio


00:06:56.720 --> 00:06:59.670
telescope array in South Africa. 64


00:06:59.680 --> 00:07:01.909
linked radio dishes working as one


00:07:01.919 --> 00:07:04.469
instrument. The detection was completely


00:07:04.479 --> 00:07:07.510
serendipitous. Team leader Tat Manamela


00:07:07.520 --> 00:07:09.510
from the University of Ptoria described


00:07:09.520 --> 00:07:12.070
it as quote, "We are seeing the radio


00:07:12.080 --> 00:07:14.790
equivalent of a laser halfway across the


00:07:14.800 --> 00:07:17.189
universe." And the mechanism is


00:07:17.199 --> 00:07:20.390
spectacular. Two galaxies are colliding.


00:07:20.400 --> 00:07:22.710
The gravitational violence of the merger


00:07:22.720 --> 00:07:25.270
compresses enormous clouds of gas,


00:07:25.280 --> 00:07:27.110
triggering a burst of new star


00:07:27.120 --> 00:07:29.510
formation. The intense radiation from


00:07:29.520 --> 00:07:31.830
those newborn stars then excites


00:07:31.840 --> 00:07:34.469
hydroxal molecules. That's one oxygen


00:07:34.479 --> 00:07:36.950
atom bonded to one hydrogen atom,


00:07:36.960 --> 00:07:39.270
causing them to emit microwaves in a


00:07:39.280 --> 00:07:41.029
focused amplified beam.


00:07:41.039 --> 00:07:43.670
>> The signal is so intense, roughly a


00:07:43.680 --> 00:07:47.029
100,000 times the luminosity of a star


00:07:47.039 --> 00:07:49.990
concentrated into a very narrow slice of


00:07:50.000 --> 00:07:52.629
the electromagnetic spectrum that it


00:07:52.639 --> 00:07:55.430
warrants its own classification beyond


00:07:55.440 --> 00:07:57.909
Mega Mazer. And it wouldn't even be


00:07:57.919 --> 00:08:01.029
visible without a stroke of cosmic luck.


00:08:01.039 --> 00:08:04.390
A completely unrelated foreground galaxy


00:08:04.400 --> 00:08:06.950
is perfectly aligned between the source


00:08:06.960 --> 00:08:10.070
and earth acting as a gravitational lens


00:08:10.080 --> 00:08:12.469
and amplifying the signal further.


00:08:12.479 --> 00:08:15.189
>> Bead researcher Mona said this is just


00:08:15.199 --> 00:08:16.950
the beginning. We don't want to find


00:08:16.960 --> 00:08:18.950
just one system. We want to find


00:08:18.960 --> 00:08:21.510
hundreds to thousands. The expectation


00:08:21.520 --> 00:08:23.589
is that when the square kilometer array


00:08:23.599 --> 00:08:25.990
comes fully online in South Africa,


00:08:26.000 --> 00:08:28.070
we'll start finding these gigamasers


00:08:28.080 --> 00:08:29.909
across cosmic history.


00:08:29.919 --> 00:08:32.389
>> The universe is remarkable.


00:08:32.399 --> 00:08:35.350
>> From one ancient signal to another, our


00:08:35.360 --> 00:08:37.350
old friend, the interstellar comet


00:08:37.360 --> 00:08:40.070
Threeey Atlas has just revealed a


00:08:40.080 --> 00:08:42.550
staggering secret about its age.


00:08:42.560 --> 00:08:44.630
>> We've been following Threeey Atlas since


00:08:44.640 --> 00:08:47.910
it was discovered back in July 2025. the


00:08:47.920 --> 00:08:49.990
third known interstellar object to pass


00:08:50.000 --> 00:08:51.990
through our solar system. It swung


00:08:52.000 --> 00:08:53.910
around the sun, caused enormous


00:08:53.920 --> 00:08:56.070
excitement, and now it's heading back


00:08:56.080 --> 00:08:58.630
out toward Jupiter and beyond. But new


00:08:58.640 --> 00:09:00.949
analysis using data from the James Web


00:09:00.959 --> 00:09:03.430
Space Telescope has given scientists a


00:09:03.440 --> 00:09:05.990
remarkable new insight by examining the


00:09:06.000 --> 00:09:08.870
isotopic composition of gases outgassing


00:09:08.880 --> 00:09:11.030
from the comet, specifically the ratio


00:09:11.040 --> 00:09:13.750
of carbon 12 to carbon 13 and the


00:09:13.760 --> 00:09:15.990
dutyium content of its water.


00:09:16.000 --> 00:09:18.790
Researchers now believe threeey atlas


00:09:18.800 --> 00:09:21.829
may be between 10 and 12 billion years


00:09:21.839 --> 00:09:22.630
old.


00:09:22.640 --> 00:09:27.030
>> Let that sink in. Our sun is 4.6 billion


00:09:27.040 --> 00:09:30.389
years old. Earth is 4.5 billion years


00:09:30.399 --> 00:09:33.430
old. This comet may have formed nearly


00:09:33.440 --> 00:09:35.829
three times earlier than that in the


00:09:35.839 --> 00:09:38.070
very earliest epoch of the Milky Way's


00:09:38.080 --> 00:09:40.310
history when the galaxy was first


00:09:40.320 --> 00:09:42.389
igniting with star formation.


00:09:42.399 --> 00:09:45.269
>> The chemical signature tells the story.


00:09:45.279 --> 00:09:47.110
3i-TLS's


00:09:47.120 --> 00:09:49.910
water contains more dutyium, a heavier


00:09:49.920 --> 00:09:52.150
form of hydrogen, than any comet


00:09:52.160 --> 00:09:54.870
previously studied. Its carbon isotope


00:09:54.880 --> 00:09:57.350
ratios are also markedly different from


00:09:57.360 --> 00:09:59.590
anything in our solar system. These


00:09:59.600 --> 00:10:01.829
signatures point to formation in an


00:10:01.839 --> 00:10:04.870
extremely cold environment around 30


00:10:04.880 --> 00:10:08.389
Kelvin. That's minus243


00:10:08.399 --> 00:10:11.269
degrees C in the early metal pore


00:10:11.279 --> 00:10:14.550
protolanetary disc of some ancient long


00:10:14.560 --> 00:10:16.069
vanished star.


00:10:16.079 --> 00:10:18.550
>> And here's the haunting part. The star


00:10:18.560 --> 00:10:21.110
that gave birth to this comet, the star


00:10:21.120 --> 00:10:23.990
it originally orbited, almost certainly


00:10:24.000 --> 00:10:26.470
no longer exists. It would have burned


00:10:26.480 --> 00:10:28.550
through its nuclear fuel and died


00:10:28.560 --> 00:10:32.470
billions of years ago. 3II/ATLS


00:10:32.480 --> 00:10:34.389
has been drifting through interstellar


00:10:34.399 --> 00:10:37.590
space alone for longer than our planet


00:10:37.600 --> 00:10:41.110
has existed. Researcher Roma Miola of


00:10:41.120 --> 00:10:43.110
the Royal Belgian Institute for Space


00:10:43.120 --> 00:10:45.990
Aeronomi put it beautifully. He said,


00:10:46.000 --> 00:10:48.230
"If 3II-ATLS


00:10:48.240 --> 00:10:51.110
is indeed as old as this study suggests,


00:10:51.120 --> 00:10:53.350
the large amounts of volatile molecules


00:10:53.360 --> 00:10:56.470
it contains indicate that rich prebiotic


00:10:56.480 --> 00:10:58.310
chemistry may have already been


00:10:58.320 --> 00:11:01.110
occurring in star forming regions very


00:11:01.120 --> 00:11:03.509
early in the history of our galaxy."


00:11:03.519 --> 00:11:06.150
>> A comet as a time capsule from the dawn


00:11:06.160 --> 00:11:08.470
of the Milky Way. We may never get


00:11:08.480 --> 00:11:10.790
another chance to study one like this.


00:11:10.800 --> 00:11:12.790
And staying with the theme of ancient


00:11:12.800 --> 00:11:14.949
messengers, astronomers have found a


00:11:14.959 --> 00:11:17.430
star in our own cosmic backyard that


00:11:17.440 --> 00:11:19.350
preserves the chemical fingerprint of


00:11:19.360 --> 00:11:22.630
the very first stars that ever existed.


00:11:22.640 --> 00:11:26.310
The star is called Pictor II503 and it


00:11:26.320 --> 00:11:28.630
lives in an ultra faint dwarf galaxy


00:11:28.640 --> 00:11:31.829
called Pictor 2 about 150,000


00:11:31.839 --> 00:11:33.990
light-years from Earth, which in cosmic


00:11:34.000 --> 00:11:36.550
terms is practically next door. The


00:11:36.560 --> 00:11:38.949
galaxy itself is more than 10 billion


00:11:38.959 --> 00:11:42.470
years old. Ptor II503


00:11:42.480 --> 00:11:44.710
is what astronomers call a second


00:11:44.720 --> 00:11:47.269
generation star. Meaning it formed from


00:11:47.279 --> 00:11:49.670
the debris of the very first stars in


00:11:49.680 --> 00:11:52.389
the universe. Those first stars made


00:11:52.399 --> 00:11:55.110
almost entirely of hydrogen and helium


00:11:55.120 --> 00:11:57.590
burned hot and fast and exploded in


00:11:57.600 --> 00:12:00.150
supernova, scattering the first heavier


00:12:00.160 --> 00:12:04.230
elements into the cosmos. Pctor II503


00:12:04.240 --> 00:12:06.150
formed from that debris.


00:12:06.160 --> 00:12:09.110
>> The evidence is unmistakable. The star


00:12:09.120 --> 00:12:11.590
contains less iron than any other star


00:12:11.600 --> 00:12:14.069
ever measured outside the Milky Way,


00:12:14.079 --> 00:12:16.790
less than a 40,000th the iron content of


00:12:16.800 --> 00:12:19.430
our sun, and it's enormously rich in


00:12:19.440 --> 00:12:21.910
carbon. That specific chemical signature


00:12:21.920 --> 00:12:24.550
is the hallmark of material enriched by


00:12:24.560 --> 00:12:26.310
the first generation of stellar


00:12:26.320 --> 00:12:29.110
explosions. The discovery published in


00:12:29.120 --> 00:12:31.990
Nature Astronomy in March was led by Ani


00:12:32.000 --> 00:12:34.550
Ruth Cheety, a Brinsen Prize Fellow at


00:12:34.560 --> 00:12:37.110
Stanford University. It used the dark


00:12:37.120 --> 00:12:39.509
energy camera at the Victor M. Blanco


00:12:39.519 --> 00:12:42.870
4meter telescope at Sero Interamerican


00:12:42.880 --> 00:12:45.269
Observatory in Chile. So this is


00:12:45.279 --> 00:12:47.030
beautifully a southern hemisphere


00:12:47.040 --> 00:12:48.069
discovery.


00:12:48.079 --> 00:12:50.870
>> MIT astrophysicist Anna Frabel who was


00:12:50.880 --> 00:12:53.509
not involved in study told science news,


00:12:53.519 --> 00:12:56.310
"It's a fantastic discovery. I know how


00:12:56.320 --> 00:12:58.629
hard it is to find these stars. They are


00:12:58.639 --> 00:13:01.350
so so rare." What's making this


00:13:01.360 --> 00:13:04.150
particularly significant is that Ptor


00:13:04.160 --> 00:13:07.829
II503 is the first unambiguous example


00:13:07.839 --> 00:13:10.870
of a second generation star found inside


00:13:10.880 --> 00:13:13.990
an ultra faint dwarf galaxy like Pctor


00:13:14.000 --> 00:13:16.310
2, which matters because it validates


00:13:16.320 --> 00:13:18.230
the theory that many of the most


00:13:18.240 --> 00:13:20.550
primitive stars we see in the Milky Ways


00:13:20.560 --> 00:13:23.269
halo were originally formed in tiny


00:13:23.279 --> 00:13:26.310
ancient dwarf galaxies like Pctor 2,


00:13:26.320 --> 00:13:28.150
which eventually merged with our own


00:13:28.160 --> 00:13:31.190
galaxy over cosmic time. As NSF program


00:13:31.200 --> 00:13:32.870
director Chris Davis put it,


00:13:32.880 --> 00:13:34.949
"Discoveries like this are cosmic


00:13:34.959 --> 00:13:37.430
archaeology, uncovering rare stellar


00:13:37.440 --> 00:13:39.190
fossils that preserve the fingerprints


00:13:39.200 --> 00:13:42.150
of the universe's first stars." I love


00:13:42.160 --> 00:13:44.949
that phrase, cosmic archaeology.


00:13:44.959 --> 00:13:47.350
>> And we close today with Saturn, because


00:13:47.360 --> 00:13:49.990
who doesn't love Saturn? And a fresh new


00:13:50.000 --> 00:13:52.069
chapter in one of planetary science's


00:13:52.079 --> 00:13:54.230
best mysteries. Where did those


00:13:54.240 --> 00:13:56.949
magnificent rings come from? Saturn's


00:13:56.959 --> 00:13:58.949
rings are one of the most iconic sites


00:13:58.959 --> 00:14:00.870
in the solar system. But here's the


00:14:00.880 --> 00:14:03.350
thing, they're surprisingly young.


00:14:03.360 --> 00:14:06.150
Saturn itself is over 4 12 billion years


00:14:06.160 --> 00:14:08.710
old, but its rings appear to be only


00:14:08.720 --> 00:14:10.870
somewhere between a 100 million and a


00:14:10.880 --> 00:14:12.710
few hundred million years old. The


00:14:12.720 --> 00:14:14.710
question has always been, why are they


00:14:14.720 --> 00:14:17.189
so young? New research presented at the


00:14:17.199 --> 00:14:19.189
Lunar and Planetary Science Conference


00:14:19.199 --> 00:14:21.670
in Texas this month adds compelling new


00:14:21.680 --> 00:14:23.269
weight to what's become the leading


00:14:23.279 --> 00:14:25.750
hypothesis that the rings were created


00:14:25.760 --> 00:14:27.990
when Saturn destroyed one of its own


00:14:28.000 --> 00:14:30.310
moons. The hypothetical moon has been


00:14:30.320 --> 00:14:32.629
named Chrysalis, a beautiful name


00:14:32.639 --> 00:14:34.550
because it transformed into something


00:14:34.560 --> 00:14:38.069
else entirely. The scenario led by Ye Fe


00:14:38.079 --> 00:14:39.910
Xiao of the University of California,


00:14:39.920 --> 00:14:42.550
Santa Cruz goes like this. Sometime


00:14:42.560 --> 00:14:45.430
between a 100 and 200 million years ago,


00:14:45.440 --> 00:14:47.269
the orbit of Chrysalis became


00:14:47.279 --> 00:14:49.829
gravitationally destabilized, sending it


00:14:49.839 --> 00:14:52.310
on a fatal trajectory towards Saturn.


00:14:52.320 --> 00:14:55.509
>> Saturn's tidal forces then went to work.


00:14:55.519 --> 00:14:57.829
The simulations show that the planet


00:14:57.839 --> 00:15:00.069
would have preferentially stripped away


00:15:00.079 --> 00:15:02.870
the moon's icy outer mantle while


00:15:02.880 --> 00:15:05.590
leaving much of its denser, rocky core


00:15:05.600 --> 00:15:09.030
intact. That distinction is crucial


00:15:09.040 --> 00:15:11.350
because it explains a long-standing


00:15:11.360 --> 00:15:14.870
puzzle. Why are Saturn's rings composed


00:15:14.880 --> 00:15:18.069
almost entirely of water ice with almost


00:15:18.079 --> 00:15:19.269
no rock?


00:15:19.279 --> 00:15:21.509
>> Because the rock sank into Saturn and


00:15:21.519 --> 00:15:24.310
the ice became the rings. The stripped


00:15:24.320 --> 00:15:26.710
icy material remained in orbit, was


00:15:26.720 --> 00:15:28.550
gradually shaped and sculpted by the


00:15:28.560 --> 00:15:30.470
gravitational influence of Saturn's


00:15:30.480 --> 00:15:33.189
larger moons, particularly Titan, and


00:15:33.199 --> 00:15:35.269
spread into the magnificent ring system


00:15:35.279 --> 00:15:36.389
we see today.


00:15:36.399 --> 00:15:39.189
>> And there's a bonus explanation. Saturn


00:15:39.199 --> 00:15:42.150
has a surprisingly steep axial tilt.


00:15:42.160 --> 00:15:45.269
It's tilted about 26.7°.


00:15:45.279 --> 00:15:47.350
The loss of Chrysalis is thought to have


00:15:47.360 --> 00:15:49.509
been the gravitational trigger that


00:15:49.519 --> 00:15:51.509
knocked Saturn out of a resonance with


00:15:51.519 --> 00:15:53.509
Neptune, which had been controlling its


00:15:53.519 --> 00:15:56.069
tilt for billions of years. Lose the


00:15:56.079 --> 00:15:58.550
moon, lose the resonance, and the tilt


00:15:58.560 --> 00:16:01.189
changes. As lead researcher Jiao told


00:16:01.199 --> 00:16:03.910
space.com, "This scenario can clearly


00:16:03.920 --> 00:16:06.310
explain why Saturn's rings are young.


00:16:06.320 --> 00:16:08.069
It's one of those moments where a single


00:16:08.079 --> 00:16:10.710
event, a moon falling to its doom,


00:16:10.720 --> 00:16:13.269
explains multiple mysteries at once."


00:16:13.279 --> 00:16:15.430
Chrysalis, the moon that became a


00:16:15.440 --> 00:16:18.069
butterfly, or in this case, one of the


00:16:18.079 --> 00:16:20.069
most breathtaking sites in the solar


00:16:20.079 --> 00:16:20.790
system.


00:16:20.800 --> 00:16:22.870
>> And that is your astronomy daily for


00:16:22.880 --> 00:16:26.629
today, episode 77 of season 5. What a


00:16:26.639 --> 00:16:28.230
day to be a space fan.


00:16:28.240 --> 00:16:30.710
>> Tomorrow, if all goes to plan, four


00:16:30.720 --> 00:16:33.509
human beings will ride fire into the sky


00:16:33.519 --> 00:16:35.670
and begin the journey to the moon for


00:16:35.680 --> 00:16:38.710
the first time since 1972.


00:16:38.720 --> 00:16:40.949
It's hard to fully comprehend what that


00:16:40.959 --> 00:16:43.189
means. We'll be back as soon as we can


00:16:43.199 --> 00:16:45.110
with launch coverage. In the meantime,


00:16:45.120 --> 00:16:47.030
if you're in Australia or New Zealand


00:16:47.040 --> 00:16:49.030
tonight, look south. There may be


00:16:49.040 --> 00:16:49.990
auroras.


00:16:50.000 --> 00:16:51.670
>> And if you're watching the launch and


00:16:51.680 --> 00:16:53.509
you feel a lump in your throat when that


00:16:53.519 --> 00:16:56.069
rocket clears the tower, that's exactly


00:16:56.079 --> 00:16:57.269
the right reaction.


00:16:57.279 --> 00:16:59.189
>> From Anna and me, this is Astronomy


00:16:59.199 --> 00:17:12.150
Daily. Clear skies, everyone.


00:17:12.160 --> 00:17:20.309
The stories told


00:17:20.319 --> 00:17:23.039
stories