NASA’s OSIRIS-Rex Spacecraft Recycled | S26E153

[00:00:00] This is SpaceTime Series 26 Episode 153 for broadcast on the 22nd of December 2023. Coming up on SpaceTime, a new mission for NASA's OSIRIS-Rex spacecraft, the discovery of a planet too big for its sun, and Halley's Comet reaches its aphelion. All that and more coming up on SpaceTime.

[00:00:44] After completing its initial seven-year sample return mission to the asteroid Bennu, NASA's OSIRIS-Rex spacecraft is moving on with a new mission to study the asteroid Apophis. Now renamed OSIRIS-Apophis Explorer, or OSIRIS-APEX for short, the spacecraft will intercept Apophis in five and a half years from now.

[00:01:03] The half-a-kilometer wide asteroid 99942 Apophis has long been a poster child for hazardous near-Earth objects. And appropriately so, the name Apophis was that of the ancient Egyptian god of chaos. In fact, NASA once classified Apophis as a potential Earth impactor.

[00:01:21] That was until more detailed observations of its orbit were able to rule that out. Still, on April 13th, 2029, Apophis will swoop past the Earth at some 7.42 kilometers per second. Now it won't impact our planet, but it will get awfully close. Skimming just 35,700 kilometers above the ground.

[00:01:43] Now to put that in perspective, that's closer than the orbits of many satellites. In fact, during the 2029 close approach, the mountain-sized space rock will be visible to observers in Europe, Africa and Western Asia without the need of a telescope or binoculars.

[00:01:58] It'll be the closest encounter of an asteroid of this size in recorded history. It'll be as bright as magnitude 3.1 and easily visible with the unaided eye from rural and darker suburban areas. Calculations suggest that were it to directly impact the Earth, the released energy would

[00:02:16] equate to about 1717 megatons of TNT. By comparison, the impact that created Meteor Crater in Arizona 50,000 years ago and the Tunguska event in Siberia in 1908 were each estimated to have only been between 3 and 10 megatons. And the biggest hydrogen bomb ever exploded, the Soviet Union's Tsar Bomba, was some 57 megatons.

[00:02:41] The shockwave from that blast circled the Earth at least three times. The exact effects of any impact with Apophis will be based on the asteroid's composition and its location and angle of impact. Still it's safe to say that any impact would decimate an area thousands of square kilometers

[00:02:57] across, creating an impact crater more than 5 kilometers wide and triggering major tsunamis, seismic activity, volcanic activity and major climate-changing debris clouds. It wouldn't be enough to destroy the planet, but it could destroy a small country.

[00:03:14] The earthquake within a radius of 10 kilometers of ground zero could reach 6.5 on the Richter Scale with wind speeds exceeding 790 meters per second. And although an impact in 2029 has now been ruled out, Apophis will have other close encounters

[00:03:29] with the Earth, and each of those encounters will change the asteroid's trajectory ever so slightly. So it's important for astronomers to study Apophis and know as much about it as possible. And so just 20 minutes after dropping off its Bernoulles sample return capsule above Earth's

[00:03:44] atmosphere on September 24th, the OSIRIS-REx spacecraft fired up its thrusters to place it on a new course to rendezvous with Apophis in 2029, just as Apophis makes its own close approach to Earth. OSIRIS-REx Deputy Principal Investigator Danny DeLaCostina from the University of Arizona,

[00:04:02] who is now the principal investigator for the OSIRIS-Apex mission, says that by April 2nd, 2029, the spacecraft's cameras will begin collecting data as it approaches the Apophis asteroid. Of course, the asteroid will also be closely observed by Earth-based telescopes.

[00:04:19] But in the hour's following closest approach, Apophis will appear too near the Sun in the sky to be observed by Earth-based optical telescopes. This means that any changes triggered by its close encounter with the Earth will be best detected by a spacecraft.

[00:04:34] And that's where OSIRIS-REx, now OSIRIS-Apex, comes in. The spacecraft will catch up with the asteroid on April 13th, just as Apophis whips past the Earth. Scientists will then spend the next 18 months studying the asteroid in detail.

[00:04:48] They'll also disturb material on the asteroid's surface with the spacecraft in order to reveal what lies underneath. Stella Kostinas says that even after the chance of a 2029 impact with Earth was finally ruled out, there was still the possibility that the encounter with the Earth could change

[00:05:03] the asteroid's trajectory, placing it on a collision course with the planet exactly seven years later in 2036. Luckily, following further observations combined with new computer modelling, Apophis now doesn't appear to pose a significant risk to Earth, at least not for the next hundred years or so.

[00:05:20] So what do we know about the asteroid so far? Well, it's a stony or S-type asteroid made up of silicate materials and nickel-iron. That makes it different from the C-type asteroid OSIRIS-REx first targeted with Bennu, which is rich in carbonaceous material.

[00:05:37] Apophis was likely formed following the collision of its parent body with another asteroid in the main asteroid belt between Mars and Jupiter. The 2029 CLOSE approach allows scientists to study Apophis' interactions with near-Earth gravitational forces, specifically tidal forces which could disturb the surface to reveal what lies beneath.

[00:05:57] Della Castina says Apophis gets close enough to the Earth so that the planet's gravitational tidal forces will impact the asteroid, causing some surface activity such as landslides or particle ejections which could create a comet-like tail.

[00:06:11] Also, we know that tidal forces and the accumulation of rubble-poor material are foundational processes which could play a role in the formation of new planets. And so these observations could inform planetary scientists how we get from debris in the early solar system to full-blown planets.

[00:06:28] Science's best guess for now is that Apophis is just a rubble-pile asteroid. Ultimately, the team hopes to understand the asteroid's evolution and characteristics, including Apophis' material strength and density. What they learn will help inform planetary defense researchers, especially because most

[00:06:45] of the potentially hazardous asteroids near the Earth are also S-types, just like Apophis. Scientists have learned a lot about C-type asteroids like Bennu thanks to the OSIRIS-REx mission. And now as OSIRIS-APEX, the spacecraft will answer even more questions about S-type asteroids.

[00:07:02] Getting up close and personal with these asteroids provides unique opportunities for planetary scientists. Currently, scientific understanding of our solar system's formation is heavily informed by meteorites, which are pieces of other celestial bodies that have fallen onto the Earth.

[00:07:18] Asteroids are the primary parent bodies of meteorites, but are usually observed from so far away they appear only as points of light in the sky that reveal little about their global properties or surface variability. The OSIRIS-REx Science Instruments Package was specifically designed to connect our understanding

[00:07:35] of meteorites to their parent asteroids or comets by placing meteorite-scale rocks into geological context. And of course, there are a lot of these vagabonds floating around in space, be they meteoroids, asteroids or comets, as this report from NASA TV explains. What's the difference between asteroids, comets and meteors?

[00:07:58] Well, they're all planetary objects orbiting the Sun. An asteroid is a small rocky object and when seen in a telescope it appears as a point of light. Some asteroids are found in a ring between the orbit of Mars and Jupiter called the asteroid belt.

[00:08:14] Some asteroids are round, some are elongated, and some even have a satellite. A comet also orbits the Sun, but unlike an asteroid, it's composed of ice and dust. So when a comet gets close to the Sun, its ice and dust contents start to vaporize.

[00:08:27] So when seen in a telescope, a comet appears fuzzy and or has a tail. So what's a meteor? Well, let's start with a meteoroid. A meteoroid is a small piece of asteroid or comet, typically pebble-sized but could

[00:08:38] be a little smaller or a little larger, and often created from a collision. When a meteoroid gets close to the Earth and enters the Earth's atmosphere, it's called a meteor. And the meteor enters the Earth's atmosphere at a very high speed, so it burns up and produces

[00:08:51] a streak of light called a shooting star. So if you've seen a shooting star, you'll likely saw a meteor. And if a meteor survives the burn and lands on the ground, it's called a meteorite. So what's the difference between asteroids, comets and meteors?

[00:09:03] Well, asteroids are rocky, comets are icy, and meteors are much smaller and are the shooting stars that you see up in the sky. And in that report from NASA TV, we heard from NASA JPL scientist Ryan Park. This is Space Time.

[00:09:17] Still to come, discovery of a planet that's too big for its own sun, and Halley's comet reaches a fillion in its journey through the solar system. All that and more still to come on Space Time.

[00:09:46] Astronomers have discovered a planet that appears to be far too massive for its host star. The findings reported in the journal Science calls into question what was previously understood about planetary formation. The planet, which has some 13.2 times the mass of the Earth, which makes it a Neptune-sized

[00:10:02] object, is on a tight 3.7 Earth-day orbit around a spectral type M red dwarf star catalogued as LHS 3154, which is about nine times less massive than our sun. The system is located some 51 light years away.

[00:10:18] The mass ratio of the newly formed planet with its host star is more than 100 times higher than the ratio of the Earth compared to the sun. The finding has revealed what is now the most massive planet known to orbit close around

[00:10:31] a red dwarf star, the least massive and coolest of all stars. The discovery goes against what current theories would predict for planetary formation around small stars, and marks the first time a planet with such a high mass has been detected orbiting around such a low-mass star.

[00:10:47] One of the study's authors, Suvrat Mehadevan from Penn State University, says the discovery really drives home the point of just how little science understands about the universe. Mehadevan says stars are formed from large clouds of molecular gas and dust.

[00:11:02] After the star is formed, gas and dust remains as disks of material orbiting around the newborn and this material can ultimately coalesce to form planets. He says the planet-forming disk around the low-mass star LHS 3154 wasn't expected to have enough material in it to form a planet.

[00:11:21] But it's clearly out there, and that calls for a re-examination of science's understanding of how planets and stars form. The authors say the heavy planetary core inferred by the team's measurements would require a larger amount of solid material in the planet-forming disk than what current models predict.

[00:11:39] The study also raises questions about prior understandings of the formation of stars, as the dust-to-mass and dust-to-gas ratio of the disks surrounding stars like LHS 3154 when they were very young and newly formed would need to be 10 times higher than what

[00:11:53] was observed in order to form a planet as massive as the one the team discovered. This is Space Time. Still to come, the famous Halley's Comet reaches perihelion in its orbit around the Sun and later in the Science Report, archaeologists have uncovered the oldest known fortified

[00:12:11] prehistoric settlement in the world. All that and more still to come on Space Time. On Saturday December the 9th, Comet P1 Halley reached aphelion, its most distant orbital position from the Sun. The moment of aphelion placed the 15-kilometer-wide mountain of rock and ice some 5.3 billion

[00:12:46] kilometers or 35.14 astronomical units from the Sun, and deep within the Kuiper Belt, the ring of comets, frozen worlds and icy debris which circles the Sun beyond the orbit of Neptune. An astronomical unit is the average distance between the Earth and the Sun, around 150 million kilometers or 8.3 light minutes.

[00:13:08] Halley's Comet is now travelling at its slowest orbital velocity, about 0.91 km per second relative to the Sun, and it's moving in the direction of the southern constellation of Hydra, the sea serpent. The event marks the midpoint for the famous comet's eternal journey through the solar

[00:13:24] system, completing each lap around the Sun in 75 Earth years. The European Southern Observatory's Very Large Telescope last imaged Comet Halley back in 2003. Back then it was at a distance of 28 astronomical units. Now having passed aphelion, it's slowly heading back towards the Sun and the warmth of the

[00:13:44] inner solar system. Its last encounter with the inner planets was way back in 1986, and its next won't be until 2061, 38 years from now. It's named after Sir Edmund Halley, who first predicted that it was a periodic comet in 1696

[00:14:01] after linking a series of cometary sightings in the same part of the sky every 75 to 79 years. These astronomers had recorded the same comet, a guest star as they described it, back in 467 BC. Another appearance of the comet in 1066 was widely seen as a portent of doom.

[00:14:20] The omen apparently proved incorrect when King Harold II was killed in the Battle of Hastings that same year, and that of course led to the ascension of William the Conqueror to the throne of England. The comet was even portrayed on the Bayeux Tapestry, which records the entire accession

[00:14:36] to the throne by William the Conqueror for posterity. Halley successfully predicted the return of the comet that now bears his name in 1758, though he didn't live long enough to see it. The designation 1P on the comet's name indicates that Halley's was the first periodic comet discovered.

[00:14:54] Periodic comets have orbits shorter than 200 years. So far some 472 have been discovered. Unfortunately the 1986 appearance of Halley's was a complete dumper for a general public eager to see the much-anticipated event. It wound up appearing very low in the south at dawn, quickly disappearing in the glare

[00:15:14] of the sun. But both the annual Etta Acherid meteor shower in April and May and the Orionids in October are generated as the Earth passes through the debris trail left behind by the passage of Halley's comet, a tantalizing taste of the event.

[00:15:29] As for comet Halley itself, well it's spending the next few decades in the direction of the constellations Hydra and later Canis Minor. And in 2050 it'll appear to pass in front of the bright star Procyon. It'll reach perihelion, its closest orbital position to the Sun, on July 28th 2061.

[00:15:48] And it may even break negative magnitudes in brightness as seen from the Earth over the following months, appearing low in the northwestern sky after dusk for northern hemisphere observers. This is Space Time.

[00:16:16] And time now to take another brief look at some of the other stories making news in science this week with the Science Report. A new study has confirmed that diet and air pollution remain among the biggest contributors globally to heart disease.

[00:16:29] A report on the global burden of heart disease shows that some 19.8 million people died around the world as a result of heart disease last year. The report breaks down death and disability trends from heart disease worldwide, regionally

[00:16:44] and nationally, and compares statistics from 2022 to how things were 30 years ago. A report in the Journal of the American College of Cardiology claims ischemic heart disease is the leading cause of heart disease-related death and high blood pressure has the most impact on day-to-day quality of life.

[00:17:03] The researchers say the number one contributor to heart disease-related lower quality of life is poor diet, while the number one environmental contributor is ambient particulate matter air pollution. Archaeologists have uncovered the oldest known fortified prehistoric settlement in the world.

[00:17:21] Scientists from the Free University of Berlin made the discovery in a remote region of Siberia saying the complex defense structures were built by hunter-gatherers around their settlements some 8,000 years ago. The findings, reported in the journal Antiquity, reshape science's understanding of early human societies.

[00:17:39] It challenges the idea that only with the advent of agriculture would people have started building permanent settlements with monumental architecture and developed complex social structures. The structures, concentrated around the settlement of Amnya, are now acknowledged as the northern-most stone age fort in Eurasia.

[00:17:57] Researchers used radiocarbon dating to establish the age of the site as the oldest known fort in the world. The prehistoric inhabitants of the area caught fish from the nearby Amnya River, and they hunted elk and reindeer using bone and stone-tipped spears.

[00:18:13] To preserve their surplus fish oil and meat, they crafted elaborately decorated pottery. So far, 10 stone age fortified sites have been discovered, each with pit houses and surrounded by earthen walls and wooden palisades, suggesting advanced agricultural and defensive capabilities. The discovery challenges the traditional view that permanent settlements accompanied

[00:18:34] by defensive structures only emerged with farming societies, thus disproving the notion that agriculture and animal husbandry were prerequisites for societal complexity. A new study has found that cats love to play fetch with their owners, especially if they're in charge.

[00:18:53] The findings, published in the journal Scientific Reports, are based on a survey of 1,000 cat owners whose cats like to play fetch in order to find out more about feline behaviour. The researchers say less than 40% of the cats' favourite objects to play fetch with were

[00:19:07] actually cat toys, with the majority preferring random household objects such as crumpled paper and hair ties. They say the cats were also more likely to keep playing longer if they were the ones who initiated the play with their owners.

[00:19:21] They say responding to your cat's attempts to play fetch with you could help the two of you bond. Megan Markle has been spotted wearing a new bit of pseudoscience, an anti-stress patch. Although at first glance it appears to look like a sticker attached to her wrist, it has

[00:19:36] since been revealed to be a $4 gadget designed to send calming signals to her brain. The 43-year-old duchess of drama raised eyebrows when pictured near her mighty CETO home wearing the mysterious blue patch. The company that make the so-called Biosignal Processing Disc claims its products are clinically

[00:19:54] proven to reduce stress and improve sleep. But Tim Mendham from Australian Skeptics says there's actually no real scientific proof to support that claim. There have been photographs around of her having a little sticker, if you like, stuck to her arm I think it was in that particular case.

[00:20:12] Basically it's what's called a Biosignal Processing Disc. That sounds very fancy. Yeah, well they're clinically proven to reduce stress and improve sleep. Whenever people say clinically proven, you have to say where and are they? And I approach many people selling little products like this and say, you're saying

[00:20:28] it's clinically proven, can you supply the results? So yeah, where was it proven? And they rarely can. It's a term that's just used. No phase 3 trial results then of 30,000 people or something? Often no result because no clinical trials but they say it is.

[00:20:43] And clinically proven sounds like a good thing. You see it in ads all the time, clinically proven. Be very careful about clinically proven. And this thing is supposed to give you the equivalent of two hours restful sleep in 20

[00:20:53] minutes just by having this sticker on you which includes I think it includes a Tesla coil and all the usual sort of energy distributing products etc. that are supposed to sort of improve your or actually make you relax more than take away the stress.

[00:21:06] I'm sure Meghan Michael's undergoing a lot of stress lately. This sounds like something we're known as a writer should be selling. I really don't know why people see celebrities as the arbiter of good sense when it comes to medical treatment but if anything probably.

[00:21:18] Why someone who's just famous for being famous should be a particular guide in your lifestyle? And I'm not quite sure what Meghan Michael's qualifications for saying this are. Certainly no scientific qualifications. She's an actress.

[00:21:28] Not to put actresses down, they probably do their job but they don't necessarily create it. She's only a second tier actress. She never made it to the top level. Then you get a sportsman like Novak Djokovic who has a range of products that he actually

[00:21:40] half-owned, the company manufacturing which he espouses and he's got things he has, he seems to have things stuck to his chest etc. again which create energy and send energy through your body but in his case, it makes him more sprightly rather than make him go to sleep.

[00:21:53] Didn't Peter Brock do the same thing in Australia years ago with some sort of catalytic energizer in his car? Peter Brock, racing car driver had a polarizer which was supposed to stick to the fuel line and improve your fuel, the energy coming out of the fuel. It didn't.

[00:22:08] It was quite a sad situation for someone who fall for this sort of thing. He definitely went into a new age belief system. He claimed that anyone else who tested it didn't do it properly, that you had to be

[00:22:17] fitted by him with a little box with nothing in it really. Just resin, the wires and that was it. They just clamped around your fuel line and was supposed to improve your fuel efficiency. There's no indication that it did that on people who tested it anyway.

[00:22:30] So sports, Novak Djokovic keeps pushing particular treatments like this, this sort of magical stickers and things. They've been around. I mean they used to have the wristbands, the power balance wristband. Cupping was a big thing too where you'd see these big blotches on them.

[00:22:44] You still seen cupping around and it's still sort of used and they believe that actually it was a big help to them. I mean sports people are often superstitious. A lot of superstitions are wear the right color underwear. But that's not looking at technology they can sell.

[00:22:55] It's their habit. If it makes them feel good, fine. If it makes them more comfortable and more confident, they can relax etc., fine. But they're not selling a product of sticker that does nothing and these things do nothing.

[00:23:07] I use a lot of gibberish, a lot of science sounding words and these things can cost hundreds and thousands of dollars. So I mean they don't come cheap and of course the old belief is that the more it costs, the better it must be.

[00:23:19] But it doesn't work that way with these particular things. Production of energy and a tiny Tesla coil to reduce certain frequencies and they throw in lots of medical terminology, the particular products, gamma immunotriic acid. That sounds scientific. It does sound scientific so it must be true.

[00:23:34] Science must be right. And people go, that's as far as they go in the investigations of these things. They say well it sounds scientific and Meghan Markle wears it so it must be working.

[00:23:44] And whenever you get a story, you're always going to get some scientists who will endorse it and other scientists who say it's rubbish. But I mean you've got to just be very careful of who is endorsing it from a health point of view.

[00:23:54] Maybe there's a placebo effect, maybe that does make you feel better if you stick it on. If you're so influenced by it, it's not going to do any proper medical treatments. It's not going to necessarily improve your play outside of your own confidence.

[00:24:05] That's Tim Mendham from Australian Sceptics.

[00:25:51] You've been listening to Spacetime with Stuart Gery. This has been another quality podcast production from bytes.com.