John Ptak investigates astrological nothingness and the night sky:
NASA’s Astronomy picture of the day
We used to get as far out, as dark out, as we could. Crispy grass under our backs as we looked up. There was no choice; it was where the constellations were. If the night sky is the holder of stories, then here in this place the stars and the stories were most true.
Today our dense urban places are the keeper of our new memories. Skies are skylines and constellations are points on spires. And while we start out in the dark, by morning, the stories, and the view, becomes clearer. What stories are we making?
[Image source: Herschel’s “The Stellar System”]
Astronomers have discovered the largest known structure in the universe, a clump of active galactic cores that stretch 4 billion light-years from end to end. The structure is a light quasar group (LQG), a collection of extremely luminous Galactic Nulcei powered by supermassive central black holes.
So that’s cool and everything, but maybe some of you would be interested to know why this is a significant find? Beyond just its record-setting bigness.
Since Einstein, physicists have accepted something called the Cosmological Principle, which states that the universe looks the same everywhere if you view it on a large enough scale. You might find some weird shit over here, and some other freaky shit over there, but if you pull back the camera far enough, you’ll find that same weird and/or freaky shit cropping up over and over again in a fairly regular distribution. This is because the universe is (probably) infinite in size and (we are pretty darn sure) has, and has always had, the same forces acting on it everywhere.
So why is this new LQG so radical? (It stands for ‘Large Quasar Group,’ btw, not ‘Light Quasar Group.’)
Well, let’s try to comprehend the scale we’re dealing with. A ‘megaparsec,’ written Mpc, is about 3.2 million light years long. The Milky Way is about 0.03 Mpc across (or 100,000 light years). The distance between our galaxy and Andromeda, our closest galactic neighbor, is 0.75 Mpc, or 2.5 million light years. LQGs are usually about 200 Mpc across. Assuming a logarithmic distribution of weird shit outliers (if you don’t know how logarithmic distribution curves work, don’t worry about it), cosmologists predicted that nothing in the universe should be more than 370 Mpc across.
This new LQG is 1200 Mpc long. That’s four billion light years. Four BILLION LIGHT YEARS. Just to travel from one side to the other of this one thing. I mean for fuck’s sake, the universe is only about 14 billion years old! How many of these things could there be?
Right now it looks like the Cosmological Principle might be out the window, unless physicists can find some way to make the existence of this new LQG work with the math (and boy, are they trying). And that’s totally baffling. It would mean—well, we don’t have any idea what it would mean. That the universe isn’t essentially uniform? That some ‘special’ physics apply/applied in some places but not in others? That Something Happened that is totally outside our current ability to understand or quantify stuff happening?
By the way, no one lives there. The radiation from so many quasars would sterilize rock.
Google Doodle celebrating the birthday of Maria Mitchell who discovered a comet in 1847. An American, Maria was awarded a medal by King Frederick VI of Denmark who established a prize for each discoverer of a “telescopic comet” that could not be seen by the naked eye.
Maria was the first female member of both the American Academy of Arts and Sciences and the American Association for the Advancement of Science. In 1865 she became Vassar College’s first professor of astronomy and director of the Vassar College Observatory. Despite her fame, Maria was initially paid less than many younger male professors, but she insisted on pay equity and received a raise.
Maria was an abolitionist and refused to wear cotton because it was harvested by enslaved people. She was also an advocate for woman’s rights and counted Elizabeth Cady Stanton among her friends.
The Tenth Planet
In 2005, a distant rock was discovered orbiting the sun in the icy, debris-filled Kuiper Belt. It’s currently about 96.6 AU from the sun—three times as far away as Pluto—and it was christened Eris, for the Greek goddess of chaos of strife, while its moon was named for Eris’s daughter, Dysnomia, the demon goddess of lawlessness. In Greek mythology, Eris stirred up jealousy and anger among the goddesses and basically started the Trojan War, so it’s a beautifully fitting name, because Eris’s discovery shook the international astronomical community and outraged the world. Some thought Eris should be classified as the tenth planet since it’s thought to be bigger than Pluto, but others disagreed because it’s smaller than our own moon, and this sparked debates over what constitutes a planet. The International Astronomical Union met in 2006, and their discussions led to Pluto’s planetary demise—they stripped it of its planethood status, reclassifying it as a dwarf planet (otherwise known as ‘plutoids’). Eris was put into that same category, never becoming a planet at all. It’s an interesting little world, though: it takes 557 years to complete a single orbit, and it’s so far away from the sun that its surface temperatures are between −243 and −217 degrees Celsius. The icy surface is dominated by nitrogen methane, similar to the surface of Pluto, and its atmosphere is most likely frozen, so Eris is extremely reflective and gleams brightly. Since it’s in an elliptical orbit, it will get closer to the sun in years to come and warm up, so hopefully we’ll learn new things about it.
Listed In Chronological Order
1) January 21 — Very Close Moon/Jupiter Conjunction
A waxing gibbous moon (78% illuminated) will pass within less than a degree to the south of Jupiter high in the evening sky. Your closed fist held out at arms length covers 10 degrees. These two wont get that close again until 2026.
2) February 2-23 — Best Evening View of Mercury
The planet Mercury will be far enough away from the glare of the Sun to be visible in the Western sky after sunset. It will be at its brightest on the 16th and dim quickly afterwards. On the 8th it will skim by the much dimmer planet Mars by about 0.4 degrees.
3) March 10-24 — Comet PANSTARRS at its best
First discovered in 2011, this comet should be coming back around for about 2 weeks. It will be visible low in the northwest sky after sunset. Here are some sources predicting what the comets may look like in the sky; 1, 2
4) April 25 — Partial Lunar Eclipse
A very minor, partial lunar eclipse (not visible in North America) where only about 2 percent of the moon’s diameter will be inside the dark shadow of the Earth.
5) May 9 — Annular Eclipse of the Sun (“Ring of Fire” Eclipse)
It will be visible in Northern Australia and parts of Papua New Guinea but mostly within the Pacific Ocean. See all the solar eclipse paths for 2001-2020 here.
6) May 24-30 — Dance of the Planets
Mercury, Venus and Jupiter will seemingly dance between each other in the twilight sky just after sunset as they will change their positions from one evening to the next. Venus will be the brightest of all, six times brighter than Jupiter.
7) June 23 — Biggest Full Moon of 2013
It will be the biggest full moon because the moon will be the closest to the Earth at this time making it a ‘supermoon’ and the tides will be affected as well creating exceptionally high and low tides for the next few days.
8) August 12 — Perseid Meteor Shower
One of the best and most reliable meteor showers of the year producing upwards of 90 meteors per hour provided the sky is dark. This year the moon won’t be in the way as much as it will set during the evening leaving the rest of the night dark. Here is a useful dark-sky finder tool.
9) October 18 — Penumbral Eclipse of the Moon
Visible mostly in Asia, Europe and Africa, at this time the 76% of the moon will be covered by the penumbral shadow of the Earth.
10) November 3 — Hybrid Eclipse of the Sun
A Hybrid Eclipse meaning, along its path, the eclipse will turn from Annular to Total and in this case most of the path will appear to be Total as there will be a slight ring of sunlight visible near the beginning of the track. This one will begin in the Atlantic (near the East Coast of the U.S.) and travel through Africa. See the path here. The greatest eclipse (with 100 seconds of totality) will appear in Liberia, near the West Coast of Africa.
11) Mid-November through December — Comet ISON
The second comet this year, ISON, could potentially be visible in broad daylight as it reaches its closest point to the Sun. It will reach that point on November 28 and it is close enough to the Sun to be categorized as a ‘Sungrazer’. Afterwards it will travel towards Earth (passing by within 40 million miles) a month later.
12) All of December — Dazzling Venus
The brightest planet of them all will shine a few hours after sundown in the Southwestern sky and for about 1.5 hours approaching New Years Eve. Around December 5th, a crescent moon will pass above the planet and the next night Venus will be at its brightest and wont be again until 2021.
13) December 13-14 — Geminid Meteor Shower
This is another great (if not the best) annual meteor shower. This year put on a show at about 120 meteors per hour and in 2013 it won’t be much different so expect another fantastic show. However, the moon - as it is a few days before full phase - will be in the way for most of the night obscuring some of the fainter meteors. You might have to stay up in the early morning hours (4am) to catch the all the meteors it has to offer. If you missed 2012’s Geminid Meteor Shower, here are some great photo-sets; 1, 2, 3
*The gif is of a total solar eclipse, from this video
Today marks the 400th anniversary of an important milestone in astronomy: German astronomer Simon Marius viewed the Andromeda Galaxy through a telescope, the first time it was viewed through a telescope, which he described looking like a ‘candle shining through a horn.’ Andromeda is the nearest spiral galaxy to the Milky Way galaxy at 2.5 million light years away and has been the object of intense study since antiquity.
For his part, if Marius is ever remembered it is usually for his dispute with Galileo. In 1614 Marius described his discovery of the Jovian moons, pre-dating his discovery several days before Galileo’s date of discovery. Although the credit usually goes to Galileo, the names for the moons came from Marius:
Io, Europa, Ganimedes puer, atque Calisto
lascivo nimium perplacuere Iovi.
Io, Europa, the boy Ganymede, and Callisto greatly pleased lustful Jupiter.
Similarly, even though Messier credits Marius with the discovery of Andromeda as a galaxy, the Persian astronomer Abd al-Rhaman al-Sufi is now credited with the discovery over 600 years earlier!
Image of Andromeda courtesy NASA. Image of Marius in the public domain.
Saturn’s B ring is spread out in all its glory in this image from Cassini. Scientists are trying to better understand the origin and nature of the various structures seen in the B ring.
Saturn’s B ring is the densest and most massive of all the rings. The C ring is also visible inside the B ring and the A ring puts on an appearance beyond the Cassini Division near the top and bottom of the image.
This view looks toward the sunlit side of the rings from about 7 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on July 22, 2012.
The view was obtained at a distance of approximately 201,000 miles (324,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 134 degrees. Image scale is 10 miles (16 kilometers) per pixel.
This new global view of Earth’s city lights is a composite assembled from data acquired by the Suomi National Polar-orbiting Partnership (NPP) satellite.
The data was acquired over nine days in April 2012 and 13 days in October 2012. It took 312 orbits to get a clear shot of every parcel of Earth’s land surface and islands. This new data was then mapped over existing Blue Marble imagery of Earth to provide a realistic view of the planet.
The image was made possible by the satellite’s “day-night band” of the Visible Infrared Imaging Radiometer Suite, which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as city lights, gas flares, auroras, wildfires and reflected moonlight.
The day-night band observed Hurricane Sandy, illuminated by moonlight, making landfall over New Jersey on the evening of Oct. 29. Night images showed the widespread power outages that left millions in darkness in the wake of the storm.
The amazing image above of a sunset on exo-planet HD209458b 150 light years away, was reconstructed by Frederic Pont of the University of Exeter using data from a camera onboard the Hubble Space Telescope.
Pont used his knowledge of how the color of light changes based on chemicals it encounters, and computer modeling, to create an actual image of what a sunset on the actual planet would look like.
The large exo planet in question, exoplanet HD209458b, nicknamed Osiris, circles its star rather closely. At certain points, when the planet passes between us and its star, the light from that star passes through Osiris’s atmosphere before reaching us, which allowed Pont to determine the chemical composition of the atmosphere and deduce what colors would appear to the naked human eye.
The light from Osiris’s star is white, like our own sun, but when it passes through the sodium in Osirisi’s atmosphere, red light in it is absorbed, leaving the starlight to appear blue. But as the sun sets, the blue light is scattered in the same way as it is here on Earth (Rayleigh scattering) causing a gradual change to green, and then to a dim dark green. And finally, due to diffraction, the bottom of the image becomes slightly flattened.
The planet Uranus has 27 known moons, the first two of which (Titania and Oberon) were discovered by the man who discovered Uranus, Sir William Hershel, in 1787. Although Herschel believed he had seen as many as 6 moons and possibly a ring, nothing more was confirmed for another 50 years when the next two moons were discovered by William Lassell, which he named Ariel and Umbriel. Lassell deviated slightly from Herschel’s naming tradition and found Umbriel in Alexander Pope’s poem the Rape of the Lock. Since then all additional moons have been named for characters from either Shakespeare or Pope.
First, moons named after characters from Shakespeare:
Next, moons named from characters from Pope:
After the two moons discovered in the 1850s, another moon wasn’t discovered for another century, in 1948. The remaining almost two dozen moons were not discovered until the Voyager 2 flyby in 1986.
Learn more about the plays (including plots, characters and full texts) at www.shakespeare-online.com. You can find Alexander Pope at www.poemhunter.com. You can also click on any of the links above for links to wikipedia.
Image of Uranus’s moons to scale courtesy NASA, in the public domain.
In case you haven’t already, check out 100,000 Stars, an interactive 3D visualization of our stellar neighbourhood. It’s a Google Chrome Experiment that draws on data from sources such as NASA and the European Space Agency to plot the stars closest to our own, helping you visualise our place in the galaxy. You can take a tour, or wander on your own. Happy exploration!
Badass Scientist of the Week: Dr. Carl Sagan
Carl Sagan (1934–1996) was an astronomer, a skeptic, a science communicator and—to many—a poet. As a child he was fascinated with the stars, and this deep sense of wonder at the universe never abated all throughout his adult life. He studied at the University of Chicago, achieving his doctorate in astronomy and astrophysics by 1960, and over the next ten years, he held teaching and research posts at various universities and observatories. In 1970, he became director of Cornell University’s Laboratory for Planetary Studies and the David Duncan Professor of Astronomy and Space Sciences. At the same time, he played a leading role as a consultant at NASA, briefing the Apollo astronauts and being closely associated with unmanned planetary missions too, most notably the Mariner, Viking, Voyager, and Galileo expeditions. His research transformed planetary science, helping to solve mysteries such as the high temperatures of Venus, the seasonal changes of Mars and the reddish haze of Titan, and he also was a pioneer of the study of extraterrestrial life—but Carl is best known as a science communicator. In his award-winning books and his enormously popular 1980 TV series Cosmos, he captured the hearts and minds of millions with his easy charisma, his ability to explain difficult concepts, and his infectious wonder for the universe. His insights about our fragile world live on today as his legacy, and the way he continues to change the public’s perception of science is perhaps his greatest achievement—showing us that examining our universe using natural curiosity and the tools of science is a joyous, awe-inspiring endeavour. Happy birthday, Carl, and thank you for everything you’ve given us.
Vulcan: The Hypothetical Planet
ercury has a curiously eccentric orbit that early astronomers had difficulty plotting. Although the Sun has the biggest gravitational influence on it, every other object in the Universe has an influence on it too according to Newton’s laws of gravitation. These are faint in comparison to the Sun’s enormous pull, but astronomers still have to factor them into calculations of Mercury’s motions. But in the mid 1800s, after painstaking calculation involving every known factor, French astronomer Urbain Jean Joseph Leverrier found that something was still unaccounted for. Neptune had just been discovered and had solved the problems with Uranus’s orbit, so rather than question Newton, Leverrier proposed in 1860 that there must be an object inside of Mercury’s orbit—a new planet that would account for irregularities. Leverrier called it Vulcan, but there was one problem: no one had ever observed it. Over the following decades, reports trickled in about various objects inside Mercury’s orbits, some perhaps small planets and others perhaps groups of asteroids. But the data didn’t match up, and no solid, consistent evidence could be provided. Controversy sprung up in the astronomical community, and yet, if Newton was correct, then there had to be another force acting on Mercury. In 1915, Einstein’s Theory of General Relativity explained it. It turns out that Newtonian gravity breaks down under extreme conditions, and relativity can step in to make corrections. Being so close to the enormous force of the Sun is certainly an extreme condition—basically, the Sun’s massive energy acts as the extra force on Mercury. When Einstein explained Mercury’s motions without the need for Vulcan, this shadow of a planet shrunk into non-existence—but it wasn’t a terrible hypothesis. Leverrier simply made the best inference he could with the available data.