I’m Thinking Of How To Structure This Whole Podcast Dealie So It’s More Interactive, And What I’ve
I’m thinking of how to structure this whole podcast dealie so it’s more interactive, and what I’ve come up with is presenting a choice at the end of each episode of what people want to hear about next. Like a choose-your-own-adventure, except the adventure is me doing more research on a topic that I mentioned in the current podcast. I will retain veto power because there are some things I DEFINITELY want to cover, but it would be a cool way to see what other people are interested in with regards to space, to history, to technology, or to people!
More Posts from Fillthevoid-with-space and Others
Does Mars Have Rings? Not Right Now, But Maybe One Day
NASA - Mars Science Laboratory (MSL) patch. March 20, 2017 As children, we learned about our solar system’s planets by certain characteristics – Jupiter is the largest, Saturn has rings, Mercury is closest to the sun. Mars is red, but it’s possible that one of our closest neighbors also had rings at one point and may have them again someday. That’s the theory put forth by NASA-funded scientists at Purdue University, Lafayette, Indiana, whose findings were published in the journal Nature Geoscience. David Minton and Andrew Hesselbrock developed a model that suggests that debris that was pushed into space from an asteroid or other body slamming into Mars around 4.3 billion years ago alternates between becoming a planetary ring and clumping together to form a moon. One theory suggests that Mars’ large North Polar Basin or Borealis Basin – which covers about 40 percent of the planet in its northern hemisphere – was created by that impact, sending debris into space. “That large impact would have blasted enough material off the surface of Mars to form a ring,” Hesselbrock said. Hesselbrock and Minton’s model suggests that as the ring formed, and the debris slowly moved away from the Red Planet and spread out, it began to clump and eventually formed a moon. Over time, Mars’ gravitational pull would have pulled that moon toward the planet until it reached the Roche limit, the distance within which a planet’s tidal forces will break apart a celestial body that is held together only by gravity.
Image above: The image from NASA’s Curiosity Mars rover shows one of Mars’ two moons, Phobos, passing directly in front of the other, Deimos, in 2013. New research suggests the moons consolidated long ago from dust rings around the planet and, in the distant future, may disintegrate into new rings. Image Credits: NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ. Phobos, one of Mars’ moons, is getting closer to the planet. According to the model, Phobos will break apart upon reaching the Roche limit, and become a set of rings in roughly 70 million years. Depending on where the Roche limit is, Minton and Hesselbrock believe this cycle may have repeated between three and seven times over billions of years. Each time a moon broke apart and reformed from the resulting ring, its successor moon would be five times smaller than the last, according to the model, and debris would have rained down on the planet, possibly explaining enigmatic sedimentary deposits found near Mars’ equator. “You could have had kilometer-thick piles of moon sediment raining down on Mars in the early parts of the planet’s history, and there are enigmatic sedimentary deposits on Mars with no explanation as to how they got there,” Minton said. “And now it’s possible to study that material.” Other theories suggest that the impact with Mars that created the North Polar Basin led to the formation of Phobos 4.3 billion years ago, but Minton said it’s unlikely the moon could have lasted all that time. Also, Phobos would have had to form far from Mars and would have had to cross through the resonance of Deimos, the outer of Mars’ two moons. Resonance occurs when two moons exert gravitational influence on each other in a repeated periodic basis, as major moons of Jupiter do. By passing through its resonance, Phobos would have altered Deimos’ orbit. But Deimos’ orbit is within one degree of Mars’ equator, suggesting Phobos has had no effect on Deimos. “Not much has happened to Deimos’ orbit since it formed,” Minton said. “Phobos passing through these resonances would have changed that.” “This research highlights even more ways that major impacts can affect a planetary body,” said Richard Zurek of NASA’s Jet Propulsion Laboratory, Pasadena, California. He is the project scientist for NASA’s Mars Reconnaissance Orbiter, whose gravity mapping provided support for the hypothesis that the northern lowlands were formed by a massive impact. Minton and Hesselbrock will now focus their work on either the dynamics of the first set of rings that formed or the materials that have rained down on Mars from disintegration of moons. Curiosity is part of NASA’s ongoing Mars research and preparation for a human mission to Mars in the 2030s. Caltech manages JPL, and JPL manages the Curiosity mission for NASA’s Science Mission Directorate in Washington. For more about Curiosity, visit: http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ For more information about NASA missions investigating Mars, visit: https://mars.nasa.gov/ Image (mentioned), Text, Credits: NASA/Laurie Cantillo/Dwayne Brown/JPL/Guy Webster/Purdue University/Steve Tally/Emil Venere/Writer: Brian Wallheimer. Best regards, Orbiter.ch Full article
This is a Trichroic Beam Splitter.
Using this splitter a white beam of light can be separated into three colours. Red, Blue and Green.
Source
Asteroid to Fly Safely Past Earth on April 19
Asteroid Watch logo. April 7, 2017
Artist’s impression of a Near-Earth Asteroid passing by Earth. Image Credit: ESA
A relatively large near-Earth asteroid discovered nearly three years ago will fly safely past Earth on April 19 at a distance of about 1.1 million miles (1.8 million kilometers), or about 4.6 times the distance from Earth to the moon. Although there is no possibility for the asteroid to collide with our planet, this will be a very close approach for an asteroid of this size. The asteroid, known as 2014 JO25, was discovered in May 2014 by astronomers at the Catalina Sky Survey near Tucson, Arizona – a project of NASA’s NEO Observations Program in collaboration with the University of Arizona. (An NEO is a near-Earth object). Contemporary measurements by NASA’s NEOWISE mission indicate that the asteroid is roughly 2,000 feet (650 meters) in size, and that its surface is about twice as reflective as that of the moon. At this time very little else is known about the object’s physical properties, even though its trajectory is well known. The asteroid will approach Earth from the direction of the sun and will become visible in the night sky after April 19. It is predicted to brighten to about magnitude 11, when it could be visible in small optical telescopes for one or two nights before it fades as the distance from Earth rapidly increases.
Asteroid 2014 JO25
Video above: This computer-generated image depicts the flyby of asteroid 2014 JO25. The asteroid will safely fly past Earth on April 19 at a distance of about 1.1 million miles (1.8 million kilometers), or about 4.6 times the distance between Earth and the moon. Video Credits: NASA/JPL-Caltech. Small asteroids pass within this distance of Earth several times each week, but this upcoming close approach is the closest by any known asteroid of this size, or larger, since asteroid Toutatis, a 3.1-mile (five-kilometer) asteroid, which approached within about four lunar distances in September 2004. The next known encounter of an asteroid of comparable size will occur in 2027 when the half-mile-wide (800-meter-wide) asteroid 1999 AN10 will fly by at one lunar distance, about 236,000 miles (380,000 kilometers). The April 19 encounter provides an outstanding opportunity to study this asteroid, and astronomers plan to observe it with telescopes around the world to learn as much about it as possible. Radar observations are planned at NASA’s Goldstone Solar System Radar in California and the National Science Foundation’s Arecibo Observatory in Puerto Rico, and the resulting radar images could reveal surface details as small as a few meters. The encounter on April 19 is the closest this asteroid has come to Earth for at least the last 400 years and will be its closest approach for at least the next 500 years. Also on April 19, the comet PanSTARRS (C/2015 ER61) will make its closest approach to Earth, at a very safe distance of 109 million miles (175 million kilometers). A faint fuzzball in the sky when it was discovered in 2015 by the Pan-STARRS NEO survey team using a telescope on the summit of Haleakala, Hawaii, the comet has brightened considerably due to a recent outburst and is now visible in the dawn sky with binoculars or a small telescope. JPL manages and operates NASA’s Deep Space Network, including the Goldstone Solar System Radar, and hosts the Center for Near-Earth Object Studies for NASA’s Near-Earth Object Observations Program, an element of the Planetary Defense Coordination Office within the agency’s Science Mission Directorate. More information about asteroids and near-Earth objects can be found at: http://cneos.jpl.nasa.gov http://www.jpl.nasa.gov/asteroidwatch For more information about NASA’s Planetary Defense Coordination Office, visit: http://www.nasa.gov/planetarydefense For asteroid and comet news and updates, follow AsteroidWatch on Twitter: https://twitter.com/AsteroidWatch Image (mentioned), Video, Text, Credits: NASA/Tony Greicius/JPL/DC Agle. Greetings, Orbiter.ch Full article
A Giant Star Factory in Neighboring Galaxy NGC 6822 NASA
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Star Discovered in Closest Known Orbit Around Likely Black Hole
NASA - Chandra X-ray Observatory patch. Astronomers have found evidence for a star that whips around a black hole about twice an hour. This may be the tightest orbital dance ever witnessed for a likely black hole and a companion star.
Image above: Artist’s illustration of a star found in the closest orbit known around a black hole in the globular cluster named 47 Tucanae. Image Credits: X-ray: NASA/CXC/University of Alberta/A.Bahramian et al.; Illustration: NASA/CXC/M.Weiss. This discovery was made using NASA’s Chandra X-ray Observatory as well as NASA’s NuSTAR and CSIRO’s Australia Telescope Compact Array (ATCA). The close-in stellar couple – known as a binary – is located in the globular cluster 47 Tucanae, a dense cluster of stars in our galaxy about 14,800 light years from Earth. While astronomers have observed this binary for many years, it wasn’t until 2015 that radio observations with the ATCA revealed the pair likely contains a black hole pulling material from a companion star called a white dwarf, a low-mass star that has exhausted most or all of its nuclear fuel. New Chandra data of this system, known as X9, show that it changes in X-ray brightness in the same manner every 28 minutes, which is likely the length of time it takes the companion star to make one complete orbit around the black hole. Chandra data also shows evidence for large amounts of oxygen in the system, a characteristic feature of white dwarfs. A strong case can, therefore, be made that the companion star is a white dwarf, which would then be orbiting the black hole at only about 2.5 times the separation between the Earth and the Moon. “This white dwarf is so close to the black hole that material is being pulled away from the star and dumped onto a disk of matter around the black hole before falling in,” said first author Arash Bahramian of the University of Alberta in Edmonton, Canada, and Michigan State University in East Lansing. “Luckily for this star, we don’t think it will follow this path into oblivion, but instead will stay in orbit.” Although the white dwarf does not appear to be in danger of falling in or being torn apart by the black hole, its fate is uncertain.
Chandra X-ray Observatory. Image Credits: NASA/CXC
“Eventually so much matter may be pulled away from the white dwarf that it ends up only having the mass of a planet,” said co-author Craig Heinke, also of the University of Alberta. “If it keeps losing mass, the white dwarf may completely evaporate.” How did the black hole get such a close companion? One possibility is that the black hole smashed into a red giant star, and then gas from the outer regions of the star was ejected from the binary. The remaining core of the red giant would form into a white dwarf, which becomes a binary companion to the black hole. The orbit of the binary would then have shrunk as gravitational waves were emitted, until the black hole started pulling material from the white dwarf. The gravitational waves currently being produced by the binary have a frequency that is too low to be detected with Laser Interferometer Gravitational-Wave Observatory, LIGO, that has recently detected gravitational waves from merging black holes. Sources like X9 could potentially be detected with future gravitational wave observatories in space. An alternative explanation for the observations is that the white dwarf is partnered with a neutron star, rather than a black hole. In this scenario, the neutron star spins faster as it pulls material from a companion star via a disk, a process that can lead to the neutron star spinning around its axis thousands of times every second. A few such objects, called transitional millisecond pulsars, have been observed near the end of this spinning up phase. The authors do not favor this possibility as transitional millisecond pulsars have properties not seen in X9, such as extreme variability at X-ray and radio wavelengths. However, they cannot disprove this explanation. “We’re going to watch this binary closely in the future, since we know little about how such an extreme system should behave”, said co-author Vlad Tudor of Curtin University and the International Centre for Radio Astronomy Research in Perth, Australia. “We’re also going to keep studying globular clusters in our galaxy to see if more evidence for very tight black hole binaries can be found.” A paper describing these results was recently accepted for publication in the Monthly Notices of the Royal Astronomical Society and is available online: https://arxiv.org/abs/1702.02167 NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations. Read More from NASA’s Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2017/47tuc/ For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra Images (mentioned), Text, Credits: NASA/Lee Mohon/Marshall Space Flight Center/Molly Porter/Chandra X-ray Center/Megan Watzke. Greetings, Orbiter.ch Full article
In November, a couple lovely people brought my attention to articles about a recent discovery that headlines consistently referred to as the ‘zombie star.’ What the heck is a zombie star? What makes it a zombie? I found a zombie star from 2014 in addition to the one in 2017 and I dug into the life cycle of the average star to get a sense of what undeath looks like in stars.
Below the cut are my sources, music credits, a vocab list, and the transcript of this episode. Suggest what you think I should research next by messaging me here, tweeting at me at @HDandtheVoid, or asking me to my face if you know me. Please subscribe on iTunes, rate it and maybe review it, and tell friends if you think they’d like to hear it! Also, welcome if you found me through PodCon!
(My thoughts on the next episode are the International Space Station, the transit of Venus, or astronaut training practices. The next episode will allegedly be up on New Year’s Day, January 1st. We’ll see about that.)
Glossary
Chandrasekhar limit - the upper limit for the mass of an astronomical body that can support extreme density without imploding: about 1.4 times the mass of our Sun. Any white dwarf star that has less than that mass will stay a white dwarf forever; any star that exceeds the Chandrasekhar limit will end in a supernova.
dwarf nova - a close binary system of a red dwarf, a white dwarf, and an accretion disk around the white dwarf. They brighten by 2 to 6 magnitudes depending on the stability of the disk, which loses material to the white dwarf. Categorized as a cataclysmic variable.
neutron star - a type of star that has gone supernova, when the surviving core is 1.5 to 3 solar masses and contracts into a small, very dense, very fast-spinning star.
nova - a close binary system of a white dwarf and a secondary star that’s a little cooler than the Sun. The system brightens 7 to 16 magnitudes in 1 to 100 days, and then the star fades slowly to the initial brightness over a period of several years or decades. At maximum brightness, it’s similar to an A or F giant star. Recurrent novae are similar to this category of variable but have several outbursts during their recorded history. Categorized as a cataclysmic variable.
pulsar - a type of neutron star that spins very, very fast. Also a kind of variable star that emits light pulses usually between 0.0014 seconds and 8.5 seconds.
reflection telescope - reflects light rays off the concave surface of a parabolic mirror to get an image of a distant object. Higher contrast image, worse color quality.
spectroscopy - the study of light from an incandescent source (or, more recently, electromagnetic radiation and other radiative energy) that has its wavelength dispersed by a prism or other spectroscopic device that can disperse an object’s wavelength. The spectra of distant astronomical objects like the Sun, stars, or nebulae are patterns of absorption lines that correspond to elements that these objects are made up of.
supernova - a massive star that explodes with a magnitude increase of 20 or more. Supernovae have led us to realize that the expansion of the Universe is accelerating.
supernova progenitors - the kinds of stars and conditions that will result in certain types of supernovae.
white dwarf star - a star that has exhausted all of its nuclear fuel (i.e. no longer has hydrogen to convert into helium through nuclear fusion). It is the hot, dense core of a star. Unless it is acquiring/accreting matter from a nearby star, it will cool over time and become a dead star.
Script/Transcript
Sources
Chandrasekhar limit via PBS, Jan 2012
“The Chandrasekhar Limit is therefore not just as upper limit to the maximum mass of an ideal white dwarf, but also a threshold. A star surpassing this threshold no longer hoards its precious cargo of heavy elements. Instead, it delivers them to the universe at large in a supernova that marks its own death but makes it possible for living beings to exist.”
Type I and Type II supernovae via Space.com
Type Ia supernovae via Swinburne University of Technology
Type Ia Supernova Progenitors via Swinburne University of Technology
Zombie star via NASA, Aug 2014
Curtis McCully “I was very surprised to see anything at the location of the supernova. We expected the progenitor system would be too faint to see, like in previous searches for normal Type Ia supernova progenitors. It is exciting when nature surprises us.”
The abstract of the article McCully and his team wrote on Type 1ax supernovae via Nature Magazine, Aug 2014
Zombie star via CNN, Nov 2017
Arcavi: "My first thought was that this must be some nearby star in our galaxy, just varying its brightness. But when we got the first spectrum of it, we saw that it was in fact a supernova 500 million light-years away. My mind was blown. The fact that it got bright and dim five times was very unusual. We'd never seen a supernova do that before."
Arcavi: "This means that we still have a lot to learn about how massive stars evolve and how they explode."
Robert Evans via Sky and Telescope, Sept 2005
2017 zombie star articles I didn’t use because there were too many of them:
Air and Space Magazine, Nov 2017
The Atlantic, Nov 2017
BBC News, Nov 2017
BGR, Nov 2017
Carnegie Science, Nov 2017
Earth Sky, Nov 2017
Express UK, Nov 2017
The Guardian, Nov 2017
Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity
Filler Music: 'Toll Free’ by the Shook Twins off their album What We Do
Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught
A podcast project to fill the space in my heart and my time that used to be filled with academic research. In 2018, that space gets filled with... MORE SPACE! Cheerfully researched, painstakingly edited, informal as hell, definitely worth everyone's time.
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