Stellar Stories: Mark Your Calendars for the Blood Moon, Hubble Tension Unravelled

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Avery: Hello, and welcome to Astronomy Daily, the

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podcast that brings you the biggest news from across the

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cosmos. I'm Avery.

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Anna: And I'm Anna. It's great to have you with us

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today. We're marking our calendars for a celestial event

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that will be seen by billion.

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Avery: That's right. We'll also be diving into a major

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cosmic puzzle, the Hubble tension and

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how some brilliant astronomers are trying to solve it.

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Anna: Then we'll come back a little closer to home to talk

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about Canada's plans to send its very first RO

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over to the Moon. And finally, a

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truly inspiring story about how an

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amateur astronomer made a cosmic discovery

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from his own backyard.

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Avery: It's a packed show, so let's get started. First

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up, Anna, tell us about this massive event we

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should all be looking forward to.

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Anna: Certainly, everyone should circle

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September 7th and 8th, 2025,

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on their calendars. On those dates, we're going to

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be treated to a total lunar eclipse, also

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known as a Blood Moon.

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Avery: And this isn't just any eclipse. The

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visibility for this one is incredible.

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We're talking over 7 billion people

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across Australia, Asia, Africa

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and Europe will have a chance to see it. It's a, uh,

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truly global event.

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Anna: Exactly. For those who might be new to this,

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a, uh, total lunar eclipse happens when the Earth passes

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directly between the sun and the Moon,

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casting a shadow on the lunar surface.

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Avery: And the Blood Moon nickname comes from that amazing

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reddish colour the Moon takes on. Right. It always

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looks so dramatic.

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Anna: It does, and there's some beautiful physics behind it.

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As sunlight passes through Earth's atmosphere, the

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atmosphere scatters the blue light, but allows

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red light to pass through and reach the Moon.

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Essentially, the Moon is being illuminated

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by all of the sunrises and sunsets happening on

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Earth at that moment.

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Avery: That's such a poetic way to think about it. So

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how long will we get to enjoy this spectacle?

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Anna: The entire event, from the moment the Earth's shadow

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first touches the Moon until it leaves, will

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last about five and a half hours. The most

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spectacular part, the totality when the

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Moon is fully in shadow, will last for an

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impressive 1 hour and 22 minutes.

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Avery: Plenty of time to get outside and take a look. And

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as if that wasn't enough, there's another eclipse, uh,

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happening right after this, isn't there?

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Anna: Yes. Just a couple of weeks later, on September

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21, 2025. This time, it's

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a partial solar eclipse, where the Moon will pass in

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front of the sun but won't cover it completely. This

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one will be visible from New Zealand, Antarctica

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and parts of Australia. So it's a busy month for

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sky watchers in the Southern Hemisphere.

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Avery: Fantastic.

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Well, from one cosmic measurement to another, let's

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talk about the expansion of the universe.

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This has been a source of some major debate in

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astronomy, right, Anna?

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Anna: A huge debate. It's a problem known as

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the Hubble tension. Put simply, different

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methods for measuring how fast the universe is

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expanding are giving us different answers. And

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the difference is significant enough that it can't be

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easily dismissed.

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Avery: So you have one group measuring the expansion based

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on the early universe, like the cosmic microwave

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background, and another group measuring it based on

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objects in the more modern universe, like

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supernovae. And their numbers don't measure match

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precisely.

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Anna: This discrepancy could mean one of two things.

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Either our measurements are wrong, or our

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fundamental understanding of physics is

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incomplete. Now, a team of Indian

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astronomers led by Professor Anupam

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Bhardija has introduced a new method that

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could help settle the debate.

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Avery: And what's their new secret weapon?

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Anna: They're using a specific type of star called

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Mira variables. These are old

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pulsating red giant stars that have a very

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predictable relationship between their pulsation

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period and their intrinsic brightness.

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By measuring how bright they appear from Earth, we

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can calculate their distance with great accuracy.

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Avery: So it's another standard candle, like the supernovae we

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use, but a totally different type of object. That's a

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great way to double check our results. And what did they find?

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Anna: Using data from the Gaia Space Telescope,

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they've managed to calculate the Hubble constant,

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that's the rate of expansion. With a precision

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of 3.7%. Their

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measurement aligns, uh, more closely with the values from

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other modern universe observations, like those

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using supernovae.

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Avery: So this strengthens the case that the discrepancy isn't

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just a measurement error. The Hubble tension might be

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real. And that means what?

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Anna: It could point to new physics, something

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we don't yet understand about the universe.

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It could affect our calculations for the age

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and size of the universe and

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deepen the mystery of dark energy. This

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discovery is a significant step in

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refining our cosmic yardstick.

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Avery: Incredible work from the edge of the universe.

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Let's bring it back to our own cosmic neighbourhood.

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We're heading back to the moon. And Canada is

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building the ride.

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Anna: That's right. As part of the Artemis programme,

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the company Canadensis Aerospace is

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developing Canada's very first

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lunar rover. It's a hugely

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exciting project, scheduled for launch in

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2029.

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Avery: It's a compact little explorer, too, only about

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35 kilogrammes. So what's its mission?

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What will it be looking for.

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Anna: The rover is headed to the moon's south

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polar region, which is a key area of

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interest for scientists. Its primary mission

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is to search for water ice. Finding

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accessible water ice is considered the holy

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grail for future lunar exploration.

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Avery: Because if you have water, you have drinking water. For

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astronauts, you can grow plants and you can

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even split the H2O into hydrogen and oxygen

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to make rocket fuel. It would be a total game changer

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for establishing a long term presence on the moon.

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Anna: Exactly. The rover also has a second

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objective to measure lunar radiation.

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Understanding the radiation environment is

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critical for ensuring the safety of future

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astronauts. But it's not going to be an easy job.

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The lunar surface is incredibly hostile.

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Avery: I'll say. The temperature swings are mind

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boggling. The rover has to be built to withstand

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everything from -200 degrees Celsius

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in the shadows to a boiling 100 degrees

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Celsius in direct sunlight.

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Anna: And then there's the lunar regolith, that

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fine abrasive dust that gets into

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everything. Navigating through it is a

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major engineering challenge. It's a testament

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to the team at Canadensis that they're taking this

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on.

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Avery: Absolutely. We'll be cheering it on in

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2029.

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Now for our final story. We're celebrating a

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different kind of explorer. One without a billion dollar

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budget, but with just as much passion.

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Anna: This is a wonderful story that really

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highlights the incredible contributions of

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amateur astronomers. It comes from Switzerland,

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where an amateur named Joseph Kaiser

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has discovered a small moon orbiting an

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asteroid.

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Avery: That's amazing. How on Earth does an amateur

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astronomer spot something like that? Asteroids are

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tiny and a moon orbiting one would be even smaller.

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Anna: He used a very clever technique called

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stellar occultation. This is when an

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object, in this case the asteroid, passes

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in front of a distant star,

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temporarily blocking its light.

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Avery: Right. So he was watching the star, expecting it to blink out

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for a moment as the main asteroid, named

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2001 PE40 passed.

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Anna: Exactly. But what he observed was

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something unexpected. After the main

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asteroid passed and the star's light returned,

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it disappeared a second time, very

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briefly. That second blink was

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caused by a smaller object trailing the

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asteroid. Its own tiny moon.

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Avery: That is brilliant. What a moment that must have been,

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realising what he'd seen. Do we know anything about

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the size of these objects?

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Anna: We do. The main asteroid is about

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12.6 kilometres long.

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Its newly discovered moon is about

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2.9 kilometres long and orbits at

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a distance of just under 24 kilometres.

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It's a significant find and a huge

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achievement for amateur astronomy.

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Avery: It really is. It goes to show that you don't need to be

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a professional with a giant observatory to make a real

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contribution to science. All you need is patience and

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skill and a clear night sky.

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Anna: A perfect story to end on.

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And that brings us to the close of another episode of

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Astronomy Daily.

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Avery: We covered a lot of ground today, from a future

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blood moon for billions to a new way of measuring our

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expanding universe, to Canada's future lunar rover.

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And a fantastic discovery by an amateur

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astronomer.

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Anna: Thank you so much for joining us. We hope you'll

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subscribe to the podcast so you don't miss an episode,

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and please visit our

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website@astronomydaily.IO for even more

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news and all our back episodes.

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Avery: Until next time, this has been Avery and

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Anna.

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Anna: Keep looking up. Uh.