“It Sounds Far Fetched Even For The Plot Of A Sci-fi Film.

The orbit of Jupiter protects the Earth from asteroids.

Galaxy NGC 7714 After Collision : Is this galaxy jumping through a giant ring of stars? Probably not. Although the precise dynamics behind the featured image is yet unclear, what is clear is that the pictured galaxy, NGC 7714, has been stretched and distorted by a recent collision with a neighboring galaxy. This smaller neighbor, NGC 7715, situated off to the left of the featured frame, is thought to have charged right through NGC 7714. Observations indicate that the golden ring pictured is composed of millions of older Sun-like stars that are likely co-moving with the interior bluer stars. In contrast, the bright center of NGC 7714 appears to be undergoing a burst of new star formation. NGC 7714 is located about 100 million light years away toward the constellation of the Fish . The interactions between these galaxies likely started about 150 million years ago and should continue for several hundred million years more, after which a single central galaxy may result. via NASA

js

Ep. 12 Longitude - HD and the Void

The hardest part of determining longitude was figuring out how sailors could find their longitudinal coordinates at sea. There were a lot of methods proposed but adding a ship into the equation makes precision difficult. Learn about the Longitude ...

The hardest part of determining longitude was figuring out how sailors could find their longitudinal coordinates at sea. There were a lot of methods proposed but adding a ship into the equation makes precision difficult. Learn about the Longitude Act of 1714 and how, even though this podcast loves astronomy, the astronomical method might not always be the best option.

Below the cut are my sources, music credits, a timeline of the astronomers and engineers and clockmakers I mention, a vocab list, a really cool resource that lets you drag continents all over a flattened map of Earth to compare their sizes at different latitudes, and the transcript of this episode. Let me know 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 in real life. And please check out the podcast on iTunes, rate it or review it if you’d like, subscribe, and maybe tell your friends about it if you think they’d like to listen!

(My thoughts on the next episode were the Voyager golden records, space race history, the transit of Venus, or maybe something about the Moon landing. I’m loving Edmond Halley again these days, too. I’m prepping to interview a friend about her graduate-level research into the history of the universe and possibly dark matter, too. Let me know by the 20th and I’ll hopefully have the next podcast up on September 25th! If not then, I’ll push for October 2nd.)

Glossary

azimuth -  a section of the horizon measured between a fixed point and the vertical circle passing through the center of an object. See example in the link. 

equator - Earth’s zero line of latitude. It’s the place on Earth where the Sun is directly overhead at noon on the vernal and autumnal equinoxes.

kamal - an Arabic navigation tool consisting of a knotted string and a piece of wood. A navigator would tie a knot in the string and, by holding it in their teeth, sight the North Star along the top of the wooden piece and the horizon along the bottom. To return home, the navigator would sail north or south to bring Polaris to the altitude they had observed in their home port, then turn left or right and sail down the latitude, keeping Polaris at a constant angle. Over time, Arab navigators started tying knots at regular intervals of a fingerwidth, called an issbah, that’s about 1 degree and 36 minutes.

magnetosphere - an invisible barrier that surrounds a celestial objet. It is often generated by the movement of the liquid metal core of the object. Around a planet, it deflects high-energy, charged particles called cosmic rays that can either come from the Sun or, less often, from interstellar space.

prime meridian - Earth’s zero degree of longitude. In current maps and time zones, this invisible, imaginary line runs through London, England.

sextant - a device used to determine an observer’s location based on the observation of a known celestial object and a lot of calculation. It is still in use by sailors.

tropic of cancer - a line of latitude that marks where the Sun will be at noon on the summer solstice.

tropic of capricorn - a line of latitude that marks where the Sun will be at noon on the winter solstice.

Script/Transcript

Sources

Longitude at Sea via The Galileo Project at Rice University

Vitamin C necessity via University of Maryland Medical Center

Scurvy via NHS

Scurvy via the Encyclopedia Britannica online

An interactive map that shows how our current map distorts land masses by letting you compare different countries’ sizes.

Sobel, Dava. Longitude. Walker & Co.; New York, 1995.

“anyone living below the Equator would melt into deformity from the horrible heat” (3).

“It simply urged Parliament to welcome potential solutions from any field of science or art, put forth by individuals or groups of any nationality, and to reward success handsomely” (53).

Timeline

Claudius Ptolemy, Greek (100-170 CE)

Johannes Werner (in Latin, Ioannis Vernerus), German (1468-1522)

Tycho Brahe, Danish (1541-1601)

Galileo Galilei, Italian (1564-1642)

Giovanni Cassini (in French, Jean-Dominique Cassini), Italian/French (1625-1712)

Christiaan Huygens, Dutch (1629-1695)

Sir Isaac Newton, English (1642-1726/7)

Ole Rømer, Danish (1644-1710)

John Flamsteed, English (1646-1719)

Edmond Halley, English (1656-1742)

John Hadley, English (1682-1744)

John Harrison, English (1693-1776)

Thomas Godfrey, American (1704-1749)

John Bird, English (1709-1776)

Larcum Kendall, English (1719-1790)

James Cook, English (1728-1779)

Nevil Maskelyne, English (1732-1811)

John Arnold, English (1736-1799)

Thomas Earnshaw, English (1749-1829)

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

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

What is an upcoming project/mission you're most excited for?

It is likely that I’ll be assigned a mission to the International Space Station (ISS) within the next few years.  We’ve had a continuous presence on the Space Station for 17 years now, along with our international partners (Russian Space Agency, European Space Agency, Japanese Space Agency, and Canadian Space Agency).  Missions on the ISS typically last 6 months.  I’m incredibly excited to contribute to the impressive array of scientific experiments that we are conducting every day on ISS (I am a scientist after all!), and very much look forward to the potential of going for a spacewalk and gaining that perspective of gazing down on the fragile blue ball that is our home from above.  Beyond that, being part of test missions on the Orion spacecraft (currently under construction at NASA!) would be an extraordinary opportunity.  The current NASA plan is to send astronauts in Orion in a mission that will go 40,000 miles beyond the Moon in the early 2020s, reaching a distance further than that ever travelled by humans.  I’d certainly be game for that! 

A ‘Ring of Fire’ solar eclipse is a rare phenomenon that occurs when the moon’s orbit is at its apogee: the part of its orbit farthest away from the Earth. Because the moon is so far away, it seems smaller than normal to the human eye. The result is that the moon doesn't entirely block out our view of the sun, but leaves an “annulus,” or ring of sunlight glowing around it. Hence the term  “annular” eclipse rather than a “total” eclipse.

China's First Lunar Rover Live-Blogged Its Own Death

The Yutu rover suffered a mysterious “abnormality” over the weekend. And the robot’s microblogged death note may make you cry.

oh gosh!

Cassini prepares for final orbital “Grand Finale” at Saturn.

Erik Wernquist, the same filmmaker who created 2014’s “Wanderers” and a stunning New Horizons promotional film in 2015, has created a new video highlighting NASA’s Cassini mission’s final days at Saturn. The Cassini spacecraft will begin its final series of orbits to cap a 13-year groundbreaking science mission known as the Grand Finale. For the first time ever in Cassini’s time at Saturn, the spacecraft will fly in between the planet’s rings and atmosphere. No spacecraft has ever before flown in this region of any of the solar system’s ringed planets. After 20 orbits, Cassini will dive into Saturn’s upper atmosphere September 15 where it will be destroyed. In 2008, mission managers explored a range of End of Mission scenarios that would protect Saturn’s moon’s from Earthly contaminants before ultimately deciding on atmospheric reentry. Cassini began her End of Mission manoeuvres on November 26, 2016, when it began the first of 20 ring-grazing orbits. A close flyby of Titan April 22 will alter the spacecraft’s trajectory to begin the first of 23 orbits in the Grand Finale, which will begin April 26.

Cassini launched from Earth on October 20, 1997, and entered Saturn orbit July 1, 2004. 16 days later, the European-built Huygens probe attached to the spacecraft landed on Titan, becoming the first probe to land in the outer solar system. Originally scheduled for a four-year mission ending in 2008, Cassini received two mission extensions in 2008 and 2010, with the latter ending in 2017. With the spacecraft’s fuel reserves low, the Cassini team decided to end the mission. P/C: JPL/Erik Wernquist

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

Light Echoes Used to Study Protoplanetary Disks : This illustration shows a star surrounded by a protoplanetary disk. A new study uses data from NASAs Spitzer Space Telescope and four ground-based telescopes to determine the distance from a star to the inner rim of its surrounding protoplanetary disk. Researchers used a method called photo-reverberation, also known as light echoes.

js