SpaceTime with Stuart Gary Series 24 Episode 35
*Scientists determine the size of the Martian core
Seismic data collected by NASA's Mars Insight lander suggests the red planet’s core is about half the size of the Earth’s.
*Searching for signs of Martian life in outback Australia
NASA’s Mars 2020 Perseverance rover is continuing its final checks following its successful touch down on the surface of the red planet.
*Kilometre wide asteroid zooms past Earth
An asteroid almost a kilometre wide has made its closest approach to Earth passing some two million kilometres from the planet’s surface.
*The Science Report
Exposure to artificial light linked to teen sleep, mood and anxiety disorders.
A new study shows young adults are having less sex these days.
Australia’s black summer bushfires pumped as much smoke into the stratosphere as a volcanic eruption.
Archaeologists discover 10,500 year old preserved large woven basket and dead sea scroll fragments.
Alex on Tech the inventor of the compact cassette passes away.
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SpaceTime Series 24 Episode 35 Transcript
[00:00:00] This is space time series 24, episode 35 for broadcast on the 31st of March, 2021. Coming up on space time. You said data suggest the red planet's core is about half the size of earth searching for signs of Marsh in life in Outback Australia, and a kilometer wide asteroid zooms the earth, all that, and more coming up.
On space time. Welcome to space time with Stuart, Gary
Seismic data collected by NASA's Mars insight. Lander suggests the red planet's core is only about half the size of earth. The findings based on instruments used to monitor Mars quakes. What's the Marshall [00:01:00] core between 36,020 and 37,020 kilometers wide insight sensors detect the sounds made by mass quakes.
The line. They began listening soon after touching down near the Martian equator in 2018. So far sensors have bought the craft of captured seismic data for around 5,000 Mars quakes. But scientists say most of the quakes on the red planet are quite small compared to those on earth, but about 50 of them measured between magnitude two and four on the open-ended Richter scale, which was strong enough to start to get at least the general picture of the red planet's interior, including the thicknesses and layers of the Martian crust and core.
Insight sensors monitor how long it takes seismic waves generated by mass quakes to pass through the different layers of the planet's interior. And this in turn can then be used to determine the density of the layer. And from that infer its composition scientists, rebel to use this data, to measure the depth of [00:02:00] the boundary between the Marsh and core and its mantle at several locations, thereby allowing them to determine the approximate size of the core.
Ma, it says an equatorial diameter of 6,792 kilometers like earth. The red planet's differentiated into a dense metallic core overlayed by less dense materials scientists initially determined the core is at least partially liquid current models imply the Marshall core is composed of iron and nickel, but with about 16 to 70% sulfur, and this iron sulfide core will be twice as rich in lighter elements as the Earth's core.
Like the earth, the machine core is surrounded by a Silicon mantle. Therefore, many of the tectonic and volcanic features on the red planet today, but unlike the earth on Mars, because it's a much smaller world, which has cooled down more quickly, these tectonic and volcanic features appear to now be dormant.
The average thickness of the red planet that's crust. It's estimated to be about 50 [00:03:00] kilometers, which is greater than the Earth's crust, which average is about 40 kilometers. Again, that's due to Mars having cooled down geologically a lot more than the earth. This is space time, still the com searching for signs of Marsh in life, in our back Australia and a kilometer wide asteroid passes the earth, all that, and more still to come.
On space. Time
is Mars 2020 perseverance rovers continue its final checks. Following it successful touchdown on the surface of the red planet. And once they're out of the way, it will begin its primary mission looking for signs of past microbial life on Mars. But that raises an important question. When NASA's newest Rover mission searches for fossilized microscopic life [00:04:00] on the red planet health site is snow.
Whether they're founded perseverance will collect rock core samples, which will then be stored in sterilized titanium containers for collection by feature sample return missions. Perseverance landed in a dry river Delta in the 45 kilometer wide jazz row. Crater in the Northern Martian hemisphere, scientists believed the sediments and debris washed into the Lake bed will provide not any, a great variety of minerals from the surrounding landscape, but also one of the best bets for finding biosignatures of ancient Martian life.
If it ever existed. The search for biosignatures we'll use the Rover suite of 19 cameras, especially mass cam Z, which can zoom in to inspect targets of interest. The rovers super cam instrument can then be used to fire a laser at a target, the generate a small plasma cloud, which can then be analyzed by a spectrometer that determined its chemical composition.
And if those data are intriguing enough, it should, managers can then order the rovers robotic arm to [00:05:00] take a closer look using a powerful x-ray beam. The search for potential chemical fingerprints of past life is another instrument of all the Rover, which will use its own laser to detect concentrations of organic molecules.
The minerals formed in water environments. One of the hopes that the Mars 2020 science team is to find a surface feature that simply couldn't be attributed to anything other than ancient microbial life. See, that's always been the problem in the past. If there is signs of life or fossilized evidence of past life in the mass media, right.
Or a mass experiment, there's always an alternative explanation. And it's Carl Sagan says extraordinary claims require extraordinary proof. So one of the things scientists will be looking for on Mars will be fossilized dramatic lights, similar to those found on earth. Stromatolites are laid microbial mats created by photosynthetic cyanobacteria.
These can build up to more than a meter in height, along the seashore, and are commonly found [00:06:00] in places like Western Australia, shock Bay. They represent some of Earth's earliest life forms and they can be found throughout the fossil record as wavy Rocky mountains and discovering similar looking structures on Mars would be very difficult to chalk up the geological processes.
To help mission scientists know exactly what to look for on the red planet required a field trip to one of the most ancient environments on earth. The Pilbara region of Outback Australia, where 3.4 billion year old fossilized stromatolites can still be found today. This report from massive TV. This in a sense is kind of a Holy grail for us.
We're in the Outback lack of Australia because this is some of the oldest convincing evidence for life on earth and the Mars 2020 mission. And the Exxon Mars mission are going to be looking for signs of life in the ancient past on Mars. And, uh, it was a great opportunity to bring the mission teams here to really [00:07:00] see for themselves what we're talking about.
When we're talking about ancient, biosignatures this part of Western Australia called the Pillbra specifically. It's really absolutely a Mecca for understanding the record of life on earth. This is one of the most important places on the planet. Geologically speaking members of the science team came out here to look at some of the oldest rocks that are on our earth.
These rocks are. Anywhere from two and a half to three and a half billion years old about the same age as the rocks that we're going to find on Mars. And what's very special about them is they have evidence of the earliest life. On earth, these wrinkly layered structures that we call stromatolites structures like this actually represent fossilized microbial mats.
A microbial mat is actually a structure preserved in the rock made by communities of millions and millions of. Micro organisms, basically fossilized pond scum in a sense, micros bacteria, living in a shallow water environment. And we believe that if life ever existed on Mars, it would have been purely microbes.
And those are left [00:08:00] behind in the record that are very distinctive. And so we've been showing the NASA and European space agency, scientists, the details of what those textures look like when we say with Mars 2020, we're seeking the signs of. Of ancient life on Mars. This is precisely the kinds of signs of life.
That we'll be seeking. I learned to be kind of a Martian to be in a harsh environment. My comfort zone is the laboratory, but you know, here I can see that this is the real stuff. It's not just simulating stuff in the laboratory. This is a real good training for us. It was really important to get the science team out here and speaking for myself.
I had seen pictures of rocks like this, and they didn't really convince me that they were the product of life. And when you see them up close and personal, it really tells the story that this was once life. And that's something you just can't get. If you don't go out and look at rocks like this, can we study it?
You can read about it, but there's nothing [00:09:00] like the practical experience of trekking around in the desert and really trying to. Think about as we land our Mars rovers there. And we look at the images provided by our sensors. How do we interpret that and follow the clues to try to find the kind of evidence that has been on earth here in Australia.
Could Mars ever have supported life and then to take the next step? Did Mars ever host life? We're just smart enough now about Mars to ask the really hard questions.
And in that report from that CTV, we heard from Mars 2020 program scientists, mid short and Wilford, and Ken Farley bought van Kranendonk from the university of new South Wales, Theresa for narrow from the European space agency's exit amass mission, and the director was neces MAs exploration program. Jim Watson.
This is space-time still the comm a kilometer wide asteroid [00:10:00] passes the earth. And later in the science report, exposure to artificial light at night, linked to teen sleep, mood and anxiety disorders, all that, and more still to come on space time.
An asteroid, almost a kilometer wide has made its closest approach to worth passing within 2 million kilometers of the planet. The mountain size space rock cataloged is 2001 fr 32 sped past at some 124,000 kilometers per hour. It's much faster than most asteroids it's unusually high speed is caused by it's highly inclined than elongated orbit around the sun, which is tilted at 39 degrees to the ecliptic Earth's orbital plane around the sun.
This orbit texts, the asteroid closer to the sun than the planet mercury before swinging back out [00:11:00] again, twice as far from the sun as Mars picks up speed during its inbound journey and then slows down again during its outward journey. The asteroids officially classified as a potentially hazardous near-Earth object.
It's highly eccentric orbit, or bring it back for another close encounter with earth in 2052. Astronomists need to study these objects and their journeys around the sun to better understand the history and dynamics of the inner solar system. They provide a valuable database of potential planetary threats to the earth and asteroid, as big as this one could devastate an entire planet.
This is space time.
And Tom Meditech. Another brief look at some of the other stories making using science this week with a science report, scientists have found that exposure to artificial light at night may affect [00:12:00] teenagers, sleep and increase their risk of mood and anxiety disorders. A report in the journal of the American medical association used satellite data to figure out which parts of the United States are exposed to high levels of artificial light at night.
They found teens in brighter areas went to bed later during the week, while those exposed to the least light slip longest on school nights. Interestingly teens in the brightest areas were also more likely to have had mood or anxiety disorders in the previous year while this type of study can't prove that nightlight actually causes sleep issues and mental disorders, researchers say that it might be best to do what you can to limit the amount of light coming into teenager's bedrooms.
And you study shows that young adults are having less sex these days. And it seems that a drop in alcohol consumption as well as an increase in guys playing computer games and living at home with their parents are to blame the study by Rutgers [00:13:00] university found that between 2007 and 2017. So this is before COVID-19 came about the percentage of 18 to 23 year old male who had casual sex in the past month drop from 38%, 24%.
And the percentage for young females in the same age group dropped from 31 to 22%. The most important fact that driving that a client among young men was the decrease in drinking, which alone explains more than 33% of the drop. But interestingly, an increase in computer video gaming explained about 25% of the change in sexual behavior among young guys.
While it seems living with the folks is still a great mood killer explaining a further 10%. For young women, about 25% of their drop in sexual activity was attributable to a decline in drinking. And you study is valid that the 2019 2020 black summer bushfires, which ravaged much of Australia pumped as much smoke into the [00:14:00] stratosphere as a volcanic eruption, a report of the journal science claims record breaking levels of atmospheric aerosols were injected into the stratosphere by the black summer fires.
The huge amounts of wildfire smoke in the stratosphere were made possible through a combination of the intensity of the fires and their location where energetic convection currents lifted smoke from the troposphere into the stratosphere, and then spread it uniformly around the planet is really, yeah.
Archeologists have discovered a perfectly preserved, large woven basket dating back some 10 and a half thousand years in a cave in the Judean desert. The artifact, which experts believe is probably the earliest of its kind ever uncovered dates back to the pre pottery neolithic period. The basket is a volume of 92 liters and was woven by two people.
One of whom was left-handed dozens of old Testament. Scroll fragments dating back to the time of Christ were also found at the site as [00:15:00] to a brightly colored Roman period, textile fragments, parts of sandals, pieces of rope, and a small comb. The more than 80 pages of parchment, scroll fragments contain verses from Zachariah eight, 16, and eight 17, which are part of the old Testament.
The fragments are thought to be part of the dead sea scrolls, a collection of some of the earliest known Jewish texts dating back some two and a half thousand years, which were discovered in desert caves near Qumran in the 1940s and fifties, the scrolls were hidden in the local caves during the bar, Kochba revolt an armed Jewish uprising against Roman rule over the lands of Judea in Israel.
Those uprisings would eventually lead to Rome's decision to forcibly remove the Jewish people from their home land, dispersing them across the Roman empire. The great Dutch inventor Lou Odense has passed away H 94 he's best known for his invention of the compact cassette cared. You'll need to [00:16:00] ask your parents where that was.
Ireland's was trained as an engineer at the prestigious technical university of Delft in the Hague Southern suburbs. Before joining the Dutch electronics conglomerate Phillips in 1952, his goal was to replace bulky reel-to-reel tape recorders with something small enough to carry in your pocket. This eventually resulted in 1962 in the invention at the compactor said whichever the next two decades became a global smash hit with more than 100 billion cassettes sold.
Alex from ity.com. We'll have more on Lou Auden's in a moment, but first Alex asks whether or not you really could live without technology for a single day. Okay. So the digital detox challenge was the test to see whether you could survive 24 hours without tech. Now that we're giving 2,400 us dollars for one person in the U S or 2,400 Australian dollars to one person in Australia.
And what you have to do was to, you know, Is connectable [00:17:00] personal technology, excluding emergencies. Of course, for 24 hours, there was no mobile phones, no TVs, no dabbing consoles or handheld Devin devices making kit as a laptop, obviously no smart watches or other wearable tech, nice smart home devices.
They couldn't be asking the smart speaker for information. Uh, but you could. They said still use a microwave to heat your food. Still a clever little thing to do in 21st century when we are so wedded to our devices and technologies that, you know, people experienced nomophobia where they don't have the phone on them.
I mean, yesterday I was in a shopping center and I couldn't feel my phone in my pocket. And I had that momentary panic. Where's my phone, you know, we live so much of our lives these days. I mean, I don't have my watch on my wrist and I'm, Oh, I've left it on the charging. And I sort of worry about these things and, um, can people really survive 24 hours without their technology?
Yeah, look, he was the inventor of the audio and the audio cassette of course, is something that, uh, young people, these guys probably don't know what it is, but for many people growing up through their lives and [00:18:00] said it was the first easy way that you could. What's something in your pocket, you could record 40th music.
When I was a kid, we would record songs off the radio or on television. You could record nights GSL. It was the first way that humans could truly in a portable basis record anything anywhere. Now, today with a mobile phone in price, we can record audio video. The little autumn was dashing inventor, and he also was instrumental part of the compact disc as well.
He worked at Phillips all of his life. He died at the age of 94 and, uh, he was one of the gripes of the 22nd Instagram have changed their rules. Tell me about it. Graham is part of Facebook and as we know, Instagram and Facebook are to be used for good. And also that can be used by people who are talking or grooming people.
And so each of them has come up with new rules that they want. To use to support parents and teens. And I guess younger children, although 13, I don't allow allowed to sign up to Instagram, but I do anyway. They're going to stop adults from sending messages to people under 18, who [00:19:00] don't already follow them.
And that this is basically something that is just, you sort of think why didn't I do this from the very beginning, but clearly, you know, we were living in. Safer more naive or innocent times. And as time has gone on, we've seen and heard of all sorts of horror stories. You know, you don't know what your kid's doing in the bedroom.
I mean, in the old days before we had smart devices advice, boys was don't let your kids have a computer in the bedroom, make sure on the computer. He's in the living room where they can be monitored. But these days with mobile phones, you know, I mean, there are stories of kids who are up at two o'clock in the morning, playing games on their phone and, and some of these kids have purchased phones themselves or got somebody else to buy it for them.
Paris bunnies. No. I mean, sometimes these days are so cheap. From ity.com
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