Cassini Prepares For Final Orbital “Grand Finale” At Saturn.

This has been going on since 1995! There are so many pictures! I gotta check these out but it will take hours. Maybe treat myself to like ten a day? It’s a better way to wake up than checking Facebook right now, I like this plan.

Shooting for an April first post date! I just started researching and hooboy, I am going to go way way way way down the rabbit hole of tangents. I think everything is interesting and cool.

Inner corona and prominences during Monday’s total solar eclipse

via reddit

UGC 12591: The Fastest Rotating Galaxy Known : Why does this galaxy spin so fast? To start, even identifying which type of galaxy UGC 12591 is difficult – it has dark dust lanes like a spiral galaxy but a large diffuse bulge of stars like a lenticular. Surprisingly observations show that UGC 12591 spins at about 480 km/sec, almost twice as fast as our Milky Way, and the fastest rotation rate yet measured. The mass needed to hold together a galaxy spinning this fast is several times the mass of our Milky Way Galaxy. Progenitor scenarios for UGC 12591 include slow growth by accreting ambient matter, or rapid growth through a recent galaxy collision or collisions – future observations may tell. The light we see today from UGC 12591 left about 400 million years ago, when trees were first developing on Earth. via NASA

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Ep. 5 Star Classifications Part 1: Leavitt and Variable Stars - HD and the Void

First in a two-part series about stars and how we classify them. Variables are a very specific kind of star that have a regular variation in brightness, like a heartbeat. They were first categorized and analyzed by Henrietta Swan Leavitt at the tu...

Stars are too distant to really peer at and they have all that radiation and heat and blinding light and such so it’s doubtful that we will ever be able to prod the Sun, but astronomers can certainly classify what stars we’ve been able to observe! This is the first part of a two-part series on star classification systems. This podcast focuses on variable stars, how they were discovered, the awesome women who started developing the basis of a major star classification system, and what variable stars did for our understanding of the universe. 

There is a lot of technical talk and I did my best to make it comprehensible but you can absolutely hit me up with questions if you have them! I’m also on Twitter at @HDandtheVoid if you’d rather ask me there. And go ahead and check out the podcast on iTunes, rate it or review it if you’d like, and subscribe! I’ll always post all the extras here on tumblr but iTunes might be more convenient for downloading and podcast apps and all that good stuff.

Below the cut is some elaboration on the episode itself, including my sources, music credits, a BIG glossary, a quote on women and emotional labor that really hits home for me, and a transcript. I mention a couple of books and quote a couple people in this episode so if you want to see that written down, those sources are there as well. Let me know what you think of this episode, let me know what you think I should research next*, tell me a fun space fact… anything’s helpful! 

*(The June 19th podcast is already set, it’s going to be part 2 on star classifications, but in July I could start talking about things like spectroscopy, planets, dark matter, or I have a book in at the library on longitude.)

Glossary:

arcsecond - an infinitesimal measurement of a degree; in 1 degree there are 3,600 arcseconds.

cosmic distance measurements: light-years - a way to imagine distance scales on an astronomical level; the distance light can travel in one year, or about 6 trillion miles. parsecs - a measurement of distance on an astronomical scale; the distance to a star that shifts by one arcsecond from one side of Earth’s orbit to the other. It’s more common than using light-years when discussing deep space astronomy. One parsec is about 19 trillion miles (30 trillion kilometers), a bit over 3 light-years.

magnitude - the measurement of a star’s brightness as seen from earth. The brighter it is, the lower its magnitude value; the Sun has an apparent magnitude of -27.

Malmquist Bias - the stars that are visible in a cluster are the brightest ones. Astronomers rely on them to compute average luminosity, but the fact that they’re the brightest ones inevitably skews the results.

parallax - the apparent shift of an object when viewed through two different lines of sight.

radial velocity - the speed at which a star is moving away from or towards Earth.

standard candle - a kind of celestial object that has a known luminosity due to some characteristic that the entire class of objects possesses.

stellar photometry - measuring and recording the magnitude of stars.

triangulation - a technique to measure the distance of an object by observing it from two different locations, knowing the distance between both observation locations and measuring the angle at which the distant object moves (its parallax angle).

variable stars: variable stars - stars that change brightness. Reasons for the brightness changes vary, and certain types of variable stars can be used to determine relative distance. They are either intrinsic (when a change in brightness is caused by a star’s own physical changes, like pulsation or eruption) or extrinsic (when the variance has an external cause, such as an eclipse of one star by another or stellar rotation). Cepheid variables - variable stars with a period between 1 and 70 days, with light variations from 0.1 to 2 magnitudes. They’re massive, with a high luminosity and are usually classified between F and G or K. They obey the period-luminosity relationship and played a major part in calculating distances to far-away galaxies as well as helping to determine the age of the Universe. eclipsing binaries - binary systems of stars where the components regularly eclipse one another, causing an apparent decrease in the brightness of the system. irregular variables - variable stars, typically red giants, without a measurable period to their luminosity. Long Period Variables - LPVs have periods ranging from 30 to 1,000 days. They’re red giants or supergiants, typically classified M, R, C, or N. There are subclasses, too: Mira, which have light variations of more than 2.5 magnitudes and are the future evolution of our own star, the Sun; and semiregular, which have some regular periods and some irregular light variation and have light variations less than 2.5 magnitudes. RR Lyrae - variable stars with a period of 0.05 to 1.2 days and a light variation between 0.3 and 2 magnitudes. They’re older and smaller than Cepheids, and are white giant stars typically classified as A. RV Tauri - variable stars that have periods between 30 and 150 days, light variation up to 3 magnitudes, and possible cycle variations that can be hundreds or thousands of days long. They’re yellow supergiants classified between G and K.

cataclysmic variables: 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. 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. R Coronae Borealis - an eruptive variable, a supergiant star that is hydrogen-poor and carbon-rich and spends most of its time at maximum light, fading as much as 9 magnitudes at irregular intervals. Most often classified between F and K or R. 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. symbiotic stars -  close binary systems of a red giant and a hot blue star. They have nova-like outbursts up to 3 magnitudes.

Script/Transcript

Sources:

What stars are made of via NASA

Stars, Cepheid Variable by T. Lloyd Evans via the California Institute of Technology aka CalTech

Variable stars via the Australia Telescope National Facility

American Association of Variable Star Observers website. I used a couple of pages from this one but the whole organization is kinda on the nose.

Stellar magnitude via EarthSky

A star magnitude scale via Harvard

Harvard Observatory’s Astronomical Photographic Plate Collection, which has a history of the collection and the women computers.

Definitions and differences for parsecs and light-years, and a description of parallax and triangulation via EarthSky

Standard candle breakdowns via some magical wonderful person with the best accessible online science book project I have ever encountered. Mad props to whoever is doing this, it’s a noble cause.

Info on Walter Baade via the Online Archives of California

A very math-y breakdown of the Malmquist Bias in the article “Observational Selection Bias Affecting the Determination of the Extragalactic Distance Scale” by P. Teerikorpi, published 1997

Johnson, George. Miss Leavitt’s Stars. Atlas Books: NY, 2005.

Henrietta Swan Leavitt quote: “It is worthy of notice [that] the brighter variables have the longer periods” (38).

“If a theory or observation seemed to suggest that we, the observers, happen to occupy an exalted place in the heavens, then it was probably wrong” (110)

Edwin Hubble quote: “With increasing distance, our knowledge fades, and fades rapidly. Eventually, we reach the dim boundary—the utmost limits of our telescopes. There, we measure shadows, and search among ghostly errors of measurements for landmarks that are scarcely more substantial” (130)

Pickover, Clifford A. “Leavitt’s Luminosity Law.” Archimedes to Hawking: Laws of Science and the Great Minds Behind Them. Oxford UP: NY, 2008. 475.

Soba, Dava. The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars. Viking: New York, 2016.

From Claire Messud’s The Woman Upstairs (I haven’t read the book, I just collect quotes, so this isn’t me endorsing the book; I know nothing about it except this paragraph): “I’m a good girl, I’m a nice girl, I’m a straight-A, strait-laced, good daughter, good career girl, and I never stole anybody’s boyfriend and I never ran out on a girlfriend, and I put up with my parents’ shit and my brother’s shit, and I’m not a girl anyhow, I’m over forty fucking years old, and I’m good at my job and I’m great with kids and I held my mother’s hand when she died, after four years of holding her hand while she was dying and I speak to my father every day on the telephone–every day, mind you, and what kind of weather do you have on your side of the river, because here it’s pretty gray and a bit muggy too? It was supposed to say ‘Great Artist’ on my tombstone, but if I died right now it would say ‘such a good teacher/daughter/friend’ instead; and what I really want to shout, and want in big letters on that grave, too, is FUCK YOU ALL.”

Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity

Filler Music: 'River Man’ by Nick Drake off his album Five Leaves Left.

Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught

No matter where you hang your stockings, I wish you a very Merry Christmas!

Deep Space Gateway to Open Opportunities for Distant Destinations

NASA logo. March 29, 2017 NASA is leading the next steps into deep space near the moon, where astronauts will build and begin testing the systems needed for challenging missions to deep space destinations including Mars. The area of space near the moon offers a true deep space environment to gain experience for human missions that push farther into the solar system, access the lunar surface for robotic missions but with the ability to return to Earth if needed in days rather than weeks or months. The period of exploration in the vicinity of the moon will begin with the first integrated mission of the Space Launch System (SLS) rocket and the Orion spacecraft, and will continue as we explore further. NASA aims to begin a cadence of one flight per year after the second mission, and the agency has established an initial set of integrated human exploration objectives combining the efforts aboard the International Space Station, SLS and Orion, and other capabilities needed to support human missions to explore deep space. Flight hardware for SLS and Orion is currently in production for the first and second missions, life support and related technologies are being tested on ISS, and habitation and propulsion development activities are also underway. NASA is working with domestic and international partners to solve the great challenges of deep space exploration. Missions in the vicinity of the moon will span multiple phases as part of NASA’s framework to build a flexible, reusable and sustainable infrastructure that will last multiple decades and support missions of increasing complexity. Deep Space Gateway This first phase of exploration near the moon will use current technologies and allow us to gain experience with extended operations farther from Earth than previously completed. These missions enable NASA to develop new techniques and apply innovative approaches to solving problems in preparation for longer-duration missions far from Earth. In addition to demonstrating the safe operation of the integrated SLS rocket and Orion spacecraft, the agency is also looking to build a crew tended spaceport in lunar orbit within the first few missions that would serve as a gateway to deep space and the lunar surface. This deep space gateway would have a power bus, a small habitat to extend crew time, docking capability, an airlock, and serviced by logistics modules to enable research. The propulsion system on the gateway mainly uses high power electric propulsion for station keeping and the ability to transfer among a family of orbits in the lunar vicinity. The three primary elements of the gateway, the power and propulsion bus and habitat module, and a small logistics module(s), would take advantage of the cargo capacity of SLS and crewed deep space capability of Orion. An airlock can further augment the capabilities of the gateway and can fly on a subsequent exploration mission, Building the deep space gateway will allow engineers to develop new skills and test new technologies that have evolved since the assembly of the International Space Station. The gateway will be developed, serviced, and utilized in collaboration with commercial and international partners.

 Lunar Space Station

“I envision different partners, both international and commercial, contributing to the gateway and using it in a variety of ways with a system that can move to different orbits to enable a variety of missions,” said William Gerstenmaier, associate administrator for Human Exploration and Operations at NASA Headquarters in Washington. “The gateway could move to support robotic or partner missions to the surface of the moon, or to a high lunar orbit to support missions departing from the gateway to other destinations in the solar system.” Deep Space Transport The second phase of missions will confirm that the agency’s capabilities built for humans can perform long duration missions beyond the moon. For those destinations farther into the solar system, including Mars, NASA envisions a deep space transport spacecraft. This spacecraft would be a reusable vehicle that uses electric and chemical propulsion and would be specifically designed for crewed missions to destinations such as Mars. The transport would take crew out to their destination, return them back to the gateway, where it can be serviced and sent out again. The transport would take full advantage of the large volumes and mass that can be launched by the SLS rocket, as well as advanced exploration technologies being developed now and demonstrated on the ground and aboard the International Space Station. This second phase will culminate at the end of the 2020s with a one year mission in the lunar vicinity to validate the readiness of the system to travel beyond the Earth-moon system to Mars and other destinations, and build confidence that long-duration, distant human missions can be safely conducted with independence from Earth. Through the efforts to build this deep space infrastructure, this phase will enable explorers to identify and pioneer innovative solutions to technical and human challenges discovered or engineered in deep space. To achieve the agency’s goal to extend humanity’s presence in the solar system will require the best research, technologies and capabilities from international partners and the private sector. NASA will look to partners for potential contributions of spaceflight hardware and the delivery of supplemental resources. The gateway and transport could potentially support mission after mission as a hub of activity in deep space near the moon, representing multiple countries and agencies with partners from both government and private industry. NASA is open to new ideas of both a technical and programmatic nature suggestions as we develop, mature and implement this plan. Related links: Journey to Mars: https://www.nasa.gov/topics/journeytomars/index.html Orion Spacecraft: https://www.nasa.gov/exploration/systems/orion/index.html Space Launch System (SLS): https://www.nasa.gov/exploration/systems/sls/index.html Image, Text, Credits: NASA/Kathryn Hambleton. Greetings, Orbiter.ch Full article

Great detail of the famous crawler that transported the mighty Saturn V and all the space shuttles to the launch pads.  An engineering feat in its own right.

Heya, if you like space maybe you’ll like this comic? It’s one of my favorites and it’s ending soon and it’s all online for freebies! The spaceships are fish and folks get to go around fixing up abandoned ruins in space. It’s utterly beautiful. It’s also ending this month!

We’ll make it out eventually. 

http://www.onasunbeam.com/

(New chapters coming soon)