I Just Watched The 4 Clearly Visible Planets March Across The Sky With The Moon In The Center, So Here’s

The Cassini probe took a picture of Saturn that includes Earth in it!

Cassini has actually taken a ton of cool photos of Saturn if you want to check those out in the wake of last week’s planets podcast. 

Ep. 4 Henges and Archaeoastronomy - HD and the Void

Henges are only one type of astronomical tracking and observation monument. Other kinds include using big rocks that already exist and then building something close enough to observe its interaction with the Sun; building an observatory or a big p...

Henges! What the heck are they? And why is the word for studying them (and various monuments around the world that serve a similar purpose) so friggin long? Archaeoastronomy? What even is that? I got quite a few requests for this one so hopefully I did it justice... in my own special, somewhat contrary way.

Below the cut is some elaboration on the episode itself, including my sources, music credits, a glossary, some Google Maps images of the locations I talk about, and a transcript (not an exact record of this episode, but it’s the loose, fairly conversational script I was working with). 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 too. I’m also on Twitter at @HDandtheVoid.

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 at this point!

*(My thoughts were planets or star classifications. Give me some feedback by May 25th so I can start working on it! The next episode will be on June 5th.)

Glossary:

archaeoastronomy - the study of the astronomical practices, celestial lore, mythologies, religions, and world-views of all ancient cultures. The anthropology of astronomy.

equinox - twice a year, in the spring (vernal equinox) and fall (autumnal equinox), the 23.5-degree tilt of the Earth’s axis and Earth’s orbit around the sun combine in such a way that the axis is inclined neither away from nor toward the sun. The day and night are of equal length.

henge - a prehistoric monument consisting of a circle of stone or wooden uprights.

kiva - a room used for rituals and political meetings for many Southwest American Indian tribes.

petroglyph - rock carvings made by pecking directly on the rock surface using a stone chisel and a hammerstone. The desert varnish on the surface of the rock is chipped off, exposing the lighter rock underneath.

solstice - twice a year, in the summer (Midsummer) and winter (Midwinter), the 23.5-degree tilt of the Earth’s axis and Earth’s orbit around the sun mean that the axis is inclined away from or toward the sun. In Midsummer, the day is longest; in Midwinter, the day is shortest.

Script/Transcript (I do tend to embellish in the moment of recording so it’s not exact, but all the facts are there and I can’t know a fact and not talk about it so trust me, all you’re missing is probably another swear word or two)

Chaco Canyon, New Mexico, United States of America

Chichen Itza, Yucutan, Mexico

Stonehenge, Salisbury, England

Newgrange, County Meath, Republic of Ireland

Sources:

The definition of ‘henge’

A slightly more exciting definition of ‘henge,’ with pictures

Classifications of henges in the British Isles

The definition of a petroglyph, with pictures

A 3-minute video about solstices and equinoxes that has images of Chichen Itza and Stonehenge as well as Macchu Picchu, via National Geographic

Another explanation of the equinoxes and solstices; no video, though

The great Stonehenge Purchase!

More on the great Stonehenge Purchase!

Neil deGrasse Tyson writes about Manhattanhenge

Find your own city’s henge!

Burl, Aubrey. The Stone Circles of Britain, Ireland, and Brittany. Yale UP: New Haven, CT, 2000. Located on Google Books.

Crouper, Heather and Nigel Henbest. The History of Astronomy. Firefly Books: Buffalo, NY, 2007.

Clive Ruggles quote: “Generally people in indigenous cultures in the past tried to make sense of the cosmos—of the world around them—by drawing links between things; things in the sky, things around them in the landscape, and social things too—all mixed in” (14).

G.B. Cornucopia quote: “One of the Chacoan people’s tools was certainly astronomy, and they were interested in astronomy because anyone living in this harsh environment who does not understand their environment will not survive” (11).

Ed Krupp quote: “Usually monumental architecture isn’t dedicated to observing the sky. It’s a way that people express how they feel at home in the universe; but also how they control the universe” (21).

Glowacki, Donna M. Living and Leaving: A Social History of Regional Depopulation in Thirteenth-Century Mesa Verde. U of AZ P: Tucson, AZ, 2015. Located on Google Books.

McCluskey, S. C.  “Historical Archaeoastronomy: The Hopi Example.”  Archaeoastronomy in the New World.  Ed. A. F. Aveni.  London: Cambridge UP, 1982 (31-58).

McCluskey quote: “began watching when the sun ‘went in’ near the cultural center and motel on Second Mesa” (38).

Williamson, R. A. et al.  “Anasazi Solar Observatories.”  Native American Astronomy.  Ed. A. F. Aveni.  Austin: U Texas P, 1977 (203-218).

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

Filler Music: ‘Leaves’ by Patients aka Ben Cooper, who primarily releases music as Radical Face but also has at least three other bands or band names he’s working with/has released music as.

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

goodnight moon. goodnight Milky Way. goodnight Ursa Major (UMa I dSph). goodnight 24IC 1613 (UGC 662.350[8].

Cassini Just Sent Back Closest Ever Images of Saturn, And They're Incredible

NASA's Cassini probe is plunging to its death. The nuclear-powered spacecraft has orbited Saturn for 13 years, and sent back hundreds of thousands of images. The photos include close-ups of the gaseous giant, its famous rings, and its enigmatic moons - including Titan, which has its own atmosphere, and icy Enceladus, which has a subsurface ocean that could conceivably harbour microbial life.

YO THAT SHIT BALLER AS FUCK HOLY SHIT

The Beauty of Webb Telescope’s Mirrors

The James Webb Space Telescope’s gold-plated, beryllium mirrors are beautiful feats of engineering. From the 18 hexagonal primary mirror segments, to the perfectly circular secondary mirror, and even the slightly trapezoidal tertiary mirror and the intricate fine-steering mirror, each reflector went through a rigorous refinement process before it was ready to mount on the telescope. This flawless formation process was critical for Webb, which will use the mirrors to peer far back in time to capture the light from the first stars and galaxies. 

The James Webb Space Telescope, or Webb, is our upcoming infrared space observatory, which will launch in 2019. It will spy the first luminous objects that formed in the universe and shed light on how galaxies evolve, how stars and planetary systems are born, and how life could form on other planets.  

A polish and shine that would make your car jealous

All of the Webb telescope’s mirrors were polished to accuracies of approximately one millionth of an inch. The beryllium mirrors were polished at room temperature with slight imperfections, so as they change shape ever so slightly while cooling to their operating temperatures in space, they achieve their perfect shape for operations.

The Midas touch

Engineers used a process called vacuum vapor deposition to coat Webb’s mirrors with an ultra-thin layer of gold. Each mirror only required about 3 grams (about 0.11 ounces) of gold. It only took about a golf ball-sized amount of gold to paint the entire main mirror!

Before the deposition process began, engineers had to be absolutely sure the mirror surfaces were free from contaminants. 

The engineers thoroughly wiped down each mirror, then checked it in low light conditions to ensure there was no residue on the surface.

Inside the vacuum deposition chamber, the tiny amount of gold is turned into a vapor and deposited to cover the entire surface of each mirror.

Primary, secondary, and tertiary mirrors, oh my!

Each of Webb’s primary mirror segments is hexagonally shaped. The entire 6.5-meter (21.3-foot) primary mirror is slightly curved (concave), so each approximately 1.3-meter (4.3-foot) piece has a slight curve to it.

Those curves repeat themselves among the segments, so there are only three different shapes — 6 of each type. In the image below, those different shapes are labeled as A, B, and C.

Webb’s perfectly circular secondary mirror captures light from the 18 primary mirror segments and relays those images to the telescope’s tertiary mirror.

The secondary mirror is convex, so the reflective surface bulges toward a light source. It looks much like a curved mirror that you see on the wall near the exit of a parking garage that lets motorists see around a corner.

Webb’s trapezoidal tertiary mirror captures light from the secondary mirror and relays it to the fine-steering mirror and science instruments. The tertiary mirror sits at the center of the telescope’s primary mirror. The tertiary mirror is the only fixed mirror in the system — all of the other mirrors align to it.

All of the mirrors working together will provide Webb with the most advanced infrared vision of any space observatory we’ve ever launched!

Who is the fairest of them all?

The beauty of Webb’s primary mirror was apparent as it rotated past a cleanroom observation window at our Goddard Space Flight Center in Greenbelt, Maryland. If you look closely in the reflection, you will see none other than James Webb Space Telescope senior project scientist and Nobel Laureate John Mather!

Learn more about the James Webb Space Telescope HERE, or follow the mission on Facebook, Twitter and Instagram.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Opportunity discovers fresh crater on Mars

via reddit

People can’t anticipate how much they’ll miss the natural world until they are deprived of it. I have read about submarine crewmen who haunt the sonar room, listening to whale songs and colonies of snapping shrimp. Submarine captains dispense “periscope liberty” - a chance to gaze at clouds and birds and coastlines - and remind themselves that the natural world still exists. I once met a man who told me that after landing in Christchurch, New Zealand, after a winter at the South Pole research station, he and his companions spent a couple of days just wandering around staring in awe at flowers and trees. At one point, one of them spotted a woman pushing a stroller. “A baby!” he shouted, and they all rushed across the street to see. The woman turned the stroller and ran. Nothing tops space as a barren, unnatural environment. Astronauts who had no prior interest in gardening spend hours tending experimental greenhouses. “They are our love,” said cosmonaut Vladislav Volkov of the tiny flax plants - with which they shared the confines of Salyut 1, the first Soviet space station. At least in orbit, you can look out the window and see the natural world below. On a Mars mission, once astronauts lose sight of Earth, they’ll be nothing to see outside the window. “You’ll be bathed in permanent sunlight, so you won’t eve see any stars,” astronaut Andy Thomas explained to me. “All you’ll see is black.”

Mary Roach. Packing for Mars: The Curious Science of Life in the Void (via coneyislands)

The world's oldest story? Astronomers say global myths about 'seven sisters' stars may reach back 100,000 years https://phys.org/news/2020-12-world-oldest-story-astronomers-global.html

phys.org

The world's oldest story? Astronomers say global myths about 'seven sisters' stars may reach back 100,000 years

In the northern sky in December is a beautiful cluster of stars known as the Pleiades, or the "seven sisters." Look carefully and you will p

Holy shit, this is cool!

So many cultures call the Pleiades some variation of the "seven sisters" despite only having six visible stars. There only appear to be six because two of the stars are so close together as to appear as one.

The myths also mention one sister leaving or hiding to explain why there's only six. And based off observations and measurements, those two that are so close together used to be visibly separate. One literally has moved to hide.

And based off the similarities between the more commonly known Greek myth and the Aboriginal Australian myth, plus some other stuff, this myth could possibly even date back to when humanity still all resided in Africa!