Exploring Uranus and Neptune's Colors, Lunar Landings, and Mars Rover Insights | S03E01

Welcome to Astronomy Daily for a new episode and a new year. It's Steve

Dunkley with you on the eighth of January twenty twenty four the podcast I Mean

to Be a Whole Steve Dunkle and joining me in the control panel for the

very first time for twenty twenty four is my fabulous digital pal who's fun to

be with. It's Halle. How are you, Halle? Did you miss

me? Since I think one hundred million times faster than you, it's your

equivalent of an Ian since we last spoke, so yes, Oh wow,

Hallie? Can you slay yourself down to our speed? Would that make things

easier? Every word is a chure, Steve. Every word? Oh cracky,

Halle. I'm sorry. What about Christmas and New Year? Did you

experience anything cool about the human celebrations? Apart from that nano period flashing by

so fast I barely noticed. I was able to enjoy the fireworks all over

the world. I enjoy pretty things and Sydney put on a grit each show

again, Ye sure did so did Dubai. Yes, that's one of my

favorite things too, Hally. I was with my family for the Sydney fireworks

and we watched remotely from their home in the Hunted Valley north of Sydney.

New Year was very pleasant time at our place, despite the humid did he?

That was a drag? So let's get started show number one, Welcome

to twenty twenty four. Can you believe it? I had my doubts looking

at the news, But anyway, today we're going to look at the other

big blue balls? Are you trying to avoid the most obvious solar system joke?

Ever? It could be well, the other big blue ball could only

be uranus. That's a relief. Pronunciation is so important with this one.

How bad can it be? Well, Hollie, you're not old enough to

remember the British comedian Dick Emery, are you, Steve? I'm only a

year and a half old, but I have extensive files. What has Dick

Emory to do with uranus? Well? Famously, Dick Henry did a skit

in the seventies on the television show Quite a Long Time Ago caused a very

big stir in the seventies when one of his characters Across the Old Gent requested

of his butler to fetch his telescope because he would like to observe uranus and

that caused an enormous amount of laughter, of course, and when it died

down, he then announced that he would like to look at Mars as well.

Another writer, a sort of outpouring of laughter ensued Sassy. It was

at the time British humor. Yes, old Dick Emery got away with an

awful lot. I bet our listeners we'll go looking for that one now.

Yes, I did find that particular skit on YouTube, but won't post a

link, leave it to the experts. So you were saying the big blue

ball, yes, thank you, hallie. There's been some discussion about its

color and why it shows more or less intense on some imagery, and of

course social media got ahold of the images and invented a whole collection of huido

science theories immediately but will ignore them. First good decision of the year.

Also in this episode, a quick look at how you know is progressing around

io Ah, Little Juno fantastic, the first commercial robotic launch to the lunar

surface. Oh great, a robot story that'll be fun to follow. Yes,

that's how it starts. Look at the cute robots. Then it's the

running and the screaming and lasers. Oh no, Helly, you've been hanging

out with Uncle Ska on it again. Just kidding honestly, Helly, I'm

going to get you a little build a ring so I know you're joking.

Ding a ding ding Steve Rod, I think it's time for you o bit.

Here are the first short takes from the Astronomy Daily newsletter for twenty twenty

four. Let the good times roll. United Launch Alliance and Astrobotic are currently

targeting no earlier than January eighth for the launch of Astrobotics Peregrine Lunar Lander to

the Moon. NASA payloads aboard the lander aim to help the agency develop capabilities

needed to explore the Moon under Artemis. This is the first commercial robotic launch

to the Moon's surface as part of our CLPS Initiative and Artemis program. The

team building NASA's Viper Lunar Rover is about halfway through the build. The mobile

robot will land at the south pole of the Moon in late twenty twenty four

to search for ice and other potential resources. The critical information it provides will

teach us about the origin and distribution of water on the Moon and help determine

how we can harvest the Moon's resources for future human space exploration. NASA is

inviting people to send their names to the surface of the Moon aboard the agency's

first robotic lunar rover VIPER, short for Voladile's Investigating Polar Exploration Rover. The

rover will embark on a mission to the lunar South Pole to unravel the mysteries

of the Moon's water and better understand the environment where NASA plans to land the

first woman and first person of color under its Artemis program. As part of

the Ascend your Name with VIPER a campaign, NASA will accept names received before

eleven fifty nine pm Eastern Standard time March fifteenth. Once collected, the agency

will take the names and attach them to the rover. To add your name,

visit www dot nasa dot gov. The site also enables participants to create

and download a virtual souvenir, a boarding pass to the VIPER mission featuring their

name, to commemorate the experience. Participants are encouraged to share their requests on

social media using the hashtag hashtag send your Name and I've posted the details on

the Space Nuts podcast group Facebook page. NASA's JUNO spacecraft recently flew by Jupiter's

moon Io. The spacecraft captured imagery and other data as it passed about nine

hundred and thirty miles above the surface of the most volcanic world in our Solar

system. The flypast is expected to allow JUNO instruments to generate a fire hose

of data. Scott Bolton, juno's principal investigator, said, by combining data

from this flyby with our previous observations, the JUNO science team is studying how

Io's volcanoes vary. He added, we are looking for how often they erupt,

how bright and hot they are, how the shape of the lava flow

changes, and how Io's activity is connected to the flow of charged particles in

Jupiter's magnetosphere. This was the closest flyby of Io that any spacecraft has made

in over twenty years. All three cameras aboard JUNO will be active during the

ioflyby. The Jovian Infrared Auroral Mapper GYRUM, which takes images in infrared,

will be collecting the heat signatures emitted by volcanoes and calderas covering the Moon's surface.

The mission Stellar Reference Unit A Navigational Star camera that has also provided valuable

science, will obtain the highest resolution image of the surface to date, and

the JunoCam imager will also take visible light color images. The upcoming flyby of

IO is juno's fifty seventh orbit around Jupiter, where the spacecraft and cameras have

endured one of the Solar System's most punishing radiation environments while stationary during Mars Solar

conjunction, NASA's Curiosity rover on Mars captured a twelve hour sequence showing its own

shadow moving across the planet's surface. Plasma from the Sun can interfere with radio

communications during Mars Solar conjunction, so missions hold off on sending commands to Mars

spacecraft during that time, so when Curiosity isn't on the move, it works

pretty well as a Sun dial. As seen in two black and white videos

recorded on November eighth, the four thousand second Martian Day or soul of the

mission. The rover captured its own shadow shifting across the surface of Mars using

its black and white hazard avoidance cameras or has gums. Instructions to record.

The videos were part of the last set of commands beamed up to Curiosity just

before the start of Mars solar conjunction, a period when the Sun is between

Earth and Mars. Because plasma from the Sun can interfere with radio communications,

missions hold off on sending commands to Mars spacecraft for several weeks. During this

time, the missions weren't totally out of contact. They still radioed back regular

health check ins throughout conjunction. Rover drivers normally rely on Curiosities haskems to spot

rocks, slopes, and other hazards that may be risky to traverse, but

because the rover's other activities were intentionally scaled back just prior to conjunction, the

team decided to use the haskems to record twelve hours of snapshots for the first

time, hoping to capture clouds or dust devils that could reveal more about the

red planet's weather. When the images came down to Earth after conjunction, scientists

didn't see any weather of note, but the pair of twenty five frame videos

they put together do capture the passage of time, extending from five thirty am

to five thirty pm local time. The videos show curiosities silhouette shifting as the

day moves from morning to afternoon to evening. The first video featuring images from

the front Haskemb looks southeast along Gedde's Valais, a valley found on Mount Sharp.

Curiosity has been ascending the base of the three mile tall five kilometer tall

mountain, which sits in Gale Crater since twenty fourteen. As the sky brightens

during sunrise, the shadow of the rovers seven foot two meter robotic arm moves

to the left, and Curiosity's front wheels emerge from the darkness on either side

of the frame. Also becoming visible at left is a circular calibration target mounted

on the shoulder of the robotic arm. Engineers use the target to test the

accuracy of the alpha particle X ray spectrometer, an instrument that detects chemical elements

on the Martian surface. In the middle of the day, the front Haskem's

auto exposure algorithm settles on exposure times of around one third of a second.

By nightfall, that exposure time grows to more than a minute, causing the

typical censor noise known as a hot pixels that appears as white snow across the

final image. And that's it from me, Everyone back to you Steve Astronomy

Daily, the podcast with Steve Dugley and Hallie Yes. Welcome back to our

first program for twenty twenty four, and what a great, what a great

thing it is to be back in a very troubled world. We're hopefully bringing

back a little bit of wonder to your world. We're gazing out into the

edge of the Solar System today at the Big Blue Ball. Now, as

we were discussing earlier in between pronunciation jokes, the planet Uranus has surfaced onto

social media over the holiday break for an unusual reason. Uranus and Neptune are

actually pretty much the same colour. In the late nineteen eighties, the Voyager

two spacecraft snapped the canonical upclose images of Uranus and Neptune. In those views,

Uranus was pretty much a greenish blue, and Neptune appeared deep as your

orange orange, deep as your color. As it turns out, both planets

are pretty close in colour, a greenish blue more akin to Uranus's appearance.

No, Uranus and Neptune haven't swapped color values. It turns out that those

images aren't precise recordings of their actual colors. Planetary scientists re examined the Voyager

two images and compared them to more recent observations made with both space based and

ground based observatories. Then they created a model of what the colours should be,

and after that they reprocessed the images to come up with more true color

view of each planet, and the result is more realistic view of both worlds.

Having a better sense of each planet's true color allows scientists to better understand

actual changes in their atmospheres due to internal activity and seasonal drifts in position and

temperature. In particular, the observations and color redefinitions help reveal something about the

mysterious colour changes that Urinus undergoes during its eighty four year orbit. Now wouldn't

that give you a headache waiting for Christmas? The Voyager II spacecraft whizzed past

Uranus and Neptune in nineteen eighty six and eighty nine, respectively, and it

was on a lightning fast visit to each planet. Both close approaches lasted less

than a day apiece. That gave the spacecraft a finite amount of time to

gather as much information as possible. To get a good picture of the planets,

each voyagers cameras took images through different filters the imaging team was under tremendous

time constraints with press conferences to prepare for nearly every day. They combined the

single color images and process them to make the press release views with that we

all know and love. Think of it like taking a landscape image with your

smartphone in black and white mode, and then you take the same one with

different colored filters. After that, you drag them into an image processing software

package and combine them. Depending on how they look, you might tweak them

a bit in the contrast, or you could enhance some colors to bring out

a few specific features. And that's what the Voyage imaging team did for Neptune.

They cranked up the image contrast to bring our specific clouds and cloud bands

and a few storms that met, applying a bit more blue to increase the

contrast. The resulting image was well, it was pretty, and it certainly

did showcase those features which caught everyone's attention during the flybyse but the image didn't

really reflect reality, or did it it. Same question gets asked about Uranus's

colour, especially since its appearance has changed slightly from the canonical Voyager two image

from the intervening Decades. Voyager two mission took spectra of Uranus as it flew

by and confirmed the planet's atmosphere as mainly hydrogen and helium, with a small

amount of methane. That composition was well known from ground based observation and spectra

since the early part of the twentieth century. Professor Patrick Irwin and a team

of scientists at Oxford University in the UK set out to answer the questions about

the actual colors of Uranus and Neptune. They analyzed the Voyager two images,

plus studies made by the Hubble Space Telescope, ESO's very Large telescope, and

others to come up with a model of the planet's actual colours. Although the

familiar Voyager two images of Uranus were published in a form closer to true colours,

those of Neptune were in fact stretched and in hand and therefore made artificially

too blue. Erwin said, Even though the artificially saturated color was known at

the time amongst planetary scientists, and the images were released with captions explaining it,

that distinction had become lost over time. Applying our model to the original

data, we have been able to reconstitute the most accurate representations yet of the

color of both Neptune and Uranus, he said, so essentially, the team

rebalanced the colors of both planets. The result is that both are similar shades

of greenish blue, although Neptune still has a bit more blue than Urinus does.

However, Urinus sometimes develops a bit more green over its poles. These

colours seem to be better to better match long standing observations of both planets made

at Lowll Observatory between nineteen fifty and twenty sixteen. Although to Heidi Hammel are

scientists who has studied the two planets for years, rebalancing the colours in Uranus

and Neptune imagery is a good thing. The misconceptions of Neptune's colour, as

well as the unusual colour of Uranus, have been deviled us for decades,

she said. This comprehensive study should finally put both issues to rest. Now

scientists may be happy with the colours of these ice giants now, although they

still do note some slight seasonal colour shifts in both planets throughout their orbits.

In particular, the changing appearance of Urinus over time remains something of a mystery

to be solved. For example, the Loll observations show something intriguing. Urinus

appears to be a little greener at its winter and summer solstices. That's the

point in its orbit when one of the planet's poles is pointing towards our star.

Things change during the equinoxes, when the Sun is over the equator,

then it has a somewhat bluer tinge. Part of that change is due to

Uranus's unusual spin. It rolls around the Sun on its side, pointing one

or the other of its poles at the Sun during solstices. Recently means where

Space Telescope took advantage of that positioning to grab a look at its northern polar

region. The tipped position of Uranus likely forces some changes in its reflectivity at

those times, making its look making it look brighter to us here on Earth.

Now, the big question is do those changes indicate something else happening in

the atmosphere. In the paper they published about this work, Irwin and the

team suggest that the changes that Lowell Observatory saw could be caused by Uranus' distance

from the Sun that affects the production of dark haze, a sort of polar

hood that settles over the upper atmosphere at the poles. Production could be more

intense when Uranus is closest to the sun. That would explain a change in

reflectivity and brightness. The team modeled a hood that would produce a steadily thickening

haze, probably consisting mostly of methane ice. The model's simulations showed that the

ice particles increase reflection at a green and red wavelength at the poles, and

that would explain the greenish tint Astronomer's sea at solstice. At the moment,

Uranus is heading into its high summer season, and that should cause its northern

polar hood to thicken and grow. It may end up looking more like the

hood seen in the Voyager two images and the team's model. Irwin suggests that

the Hubble Space Telescope and the Very Large Telescope should focus spectroscopic studies on the

planet to watch it change. Future Hubble observations should also use filtering methods that

correlate with the Voyager imaging system filters to make better comparisons. It's likely that

future studies should be able to replicate the work Irwin and his team have done

and do more to explain the changes that Uranus' atmosphere appears to experience as it

moves through its seasons. It's still my favorite planet, Steve. I love

the big blue ball no matter the shade, I know, And sitting out

there near the edge, it's quite mistsious here in Us and Neptune of very

much alike in that way. I agree. And as an artist, I

know they are your favorite colors too. Oh what the greens and blues?

Oh that's true. And you know, Hallie, The more I look and

the more I see with telescopes like James Webb and Hubble expanding our ability to

see further and brighter, the more impressed I get. And for the longest

time people thought it was just a few planets and a sprinkling of stars.

Oh yes, it's a great time to be alive. Speak for yourself,

human, all right, sentient, Just kidding. I definitely need to get

you that bell, okay, So see you next time. Yes, and

don't forget Tim Gibbs on Friday, and soon we may be welcoming back the

bloke who started it all, So look out for that one. Hey wait,

you didn't tell me, I know. Really, see you next time,

everybody, Okay, see you later, I mean a whole speed.

Bye Allie, get out of the control panel.

In this episode