primordialbitch
i just think black holes are neat
52 posts
Latest Posts by primordialbitch
Motion is Curved and All Curvature is Spiral" - Walter Russell
This first image from NASA’s James Webb Space Telescope is the deepest and sharpest infrared image of the distant universe to date. Known as Webb’s First Deep Field, this image of galaxy cluster SMACS 0723 is overflowing with detail. Thousands of galaxies – including the faintest objects ever observed in the infrared – have appeared in Webb’s view for the first time. This slice of the vast universe covers a patch of sky approximately the size of a grain of sand held at arm’s length by someone on the ground.
NASA’s Webb Space Telescope Reveals Astounding, Unprecedented Views of the Universe
seeing the photos from Webb up against photos from Hubble just makes me… I don’t even know like, wow! Look at that!
shit man this got me emotional
Ancient Bronze Age city reemerges from Iraq river after extreme drought
When an extreme drought caused a 3,400-year-old city to reemerge from a reservoir on the Tigris River in northern Iraq, archaeologists raced to excavate it before the water returned.
The Bronze Age city, at an archaeological site called Kemune, is a relic of the Mittani Empire (also spelled Mitanni Empire), an ancient kingdom that ruled parts of northern Mesopotamia from around 1500 B.C. to 1350 B.C. Researchers have long known of the remains of the city, but they can only investigate them during droughts.
Archaeologists partly excavated Kemune in 2018 and discovered a lost palace with 22-foot-high (7 meters) walls and chambers decorated in painted murals, Live Science previously reported. This time, researchers mapped most of the city, including an industrial complex and a multistory storage facility that likely held goods from all over the region, according to a statement released by the University of Tübingen in Germany. Read more.
Red paint on 1,000-year-old gold mask from Peru contains human blood proteins
Thirty years ago, archeologists excavated the tomb of an elite 40-50-year-old man from the Sicán culture of Peru, a society that predated the Incas. The man’s seated, upside-down skeleton was painted bright red, as was the gold mask covering his detached skull. Now, researchers reporting in ACS’ Journal of Proteome Research have analyzed the paint, finding that, in addition to a red pigment, it contains human blood and bird egg proteins.
The Sicán was a prominent culture that existed from the ninth to 14th centuries along the northern coast of modern Peru. During the Middle Sicán Period (about 900–1,100 A.D.), metallurgists produced a dazzling array of gold objects, many of which were buried in tombs of the elite class. In the early 1990s, a team of archaeologists and conservators led by Izumi Shimada excavated a tomb where an elite man’s seated skeleton was painted red and placed upside down at the center of the chamber. Read more.
planetarium presenters trying to explain to a busload of 4th graders how incomprehensibly vast space is
Here’s one good thing to come out of 2020:
Paleontologists completed a life-sized replica of Sue, the most complete T. Rex ever found.
And she is freaking GORGEOUS!
As I read more about this beauty, I found out some new details regarding things I thought I previously knew about the beast that was Tyrannosaurus Rex, and I’m going to share them with you.
First, and most obvious, her size:
This is nothing new, we all figured T. Rex was big, but I for one never stopped to consider exactly how big it was. Nobody ever really knows what to imagine when they read about something the size of a whale that walked around and ate everything it could kill.
Speaking of eating things, I just want to remind you all that T. Rex had–by miles–the strongest bite of any terrestrial animal living or dead, somewhere around six and a half tons of force. That’s over six times greater than the current estimate of what Allosaurus was capable of, and three times what was delivered by the highest measured reading of the living title holder–the estuarine crocodile. It didn’t have to waste time swinging its head open-mouthed like Saurophaganax for a little extra oomph, or grow fancy serrated teeth like Carcharodontosaurus to cut pieces out of its prey. It opted for the simplest approach: get its mouth around something and crush it to death; imagine the full weight of an elephant on whatever was between this thing’s jaws.
“How did it find something to eat?” I hear you asking. “It can’t see something if it doesn’t move, right?”
Listen, I love Jurassic Park too, but that’s a big crock of shit.
Notice how both her eyes face forward. That gives her binocular vision (the ability to focus both eyes on one target, like you and I). More importantly it means she has impeccable depth perception due to overlapping fields of vision from each, large, eyeball. Researchers agree that T. Rex not only had incredible vision, but that it was probably better than most modern animals–including eagles, hawks, and owls–and that she could likely spot something three and a half miles away. If something that big can see that well, it doesn’t matter if you move or not, she’d be able to tell if it was an animal trying to hide or a piece of vegetation. So pray she isn’t hungry if she lays eyes on you. And even if by some miracle she didn’t see you, she’d still smell you.
If she decided you looked tasty, you probably wouldn’t hear her coming as much as you’d feel her. Modern science indicates that T. Rex didn’t roar like in Jurassic Park, but rather bellowed or maybe even hissed like crocodilians. If she were on to you, you’d most likely feel this sense of unease creep up your spine as a low-pitched rumble in the air permeated through you. You wouldn’t know what it was or where it was coming from until you hear her footfalls. By then it’s too late–you could try to run but she’d probably catch you. There’s plenty on YouTube that reconstructs what T. Rex may have sounded like, and it’s legitimately haunting.
To wrap all of this up, the one bit of good that came out of the cursed year that is 2020 is that this wonderful child of science and art came into the world, and reaffirmed my respect and admiration for the eight ton slab of muscle and teeth that is this magnificent creature.
…and it is nothing if not magnificent.
in mesopotamia there were no 'cover letters' or 'curriculum vitaes'. there were just, pots.
翼善冠yi-shan-guan, a type of hat in Chinese hanfu for ancient emperors and kings.
The term first appeared in Tang Dynasty and invented by Emperor Taizong of Tang. Quotes according to the official records of Tang, Song and Ming Dynasty. “唐贞观中，太宗采古制为翼善冠，自服之。朔望视朝，以常服及帛练裙襦通着之。若服袴褶，又与平巾帻通用。见宋王溥《唐会要．舆服上》﹑《旧唐书．舆服志》。明永乐三年，定皇帝常服冠以乌纱覆之，折角向上，亦名翼善冠。见《明史．舆服志二》。”
The yishanguan also has a corresponding hat of very similar shape in the official class and the commoner class, called wushamao乌纱帽, and in fact the yishanguan can be considered a variant of wushamao.
Actually yishanguan does have another name, called wu-sha-zhe-shang-jin乌纱折上巾, which means a hat made of black gauze with folded wings upward, and that’s what distinguishes it from an ordinary wushamao.
As for the origin of wushamao, it is futou幞头 in the Tang Dynasty. Futou in the Tang Dynasty originates from fujin幅巾 in the Han Dynasty. In the Han Dynasty, people wrapped their heads in a whole pair of soft cloth, so it was called fujin幅巾(It literally means a whole piece of cloth).
Some wushamao without wings, worn by officials, are similar in shape to the Yishanguan worn by the emperor. In Chinese historical dramas and costume dramas, jin-yi-wei锦衣卫, the imperial guards of secret service agent in the emperor’s court often wore this kind of wushamao without wings. And most wushamao have flush, long oval wings. There is a type of wushamao with particularly slender wings that is inherited from the Song Dynasty and is considered more formal.
The pictures below are ancient wushamao from the museums’ collection, as well as portraits of Ming Dynasty officials.
Because jinyiwei锦衣卫 resembles ancient agents, it is very popular among Chinese artists, who often draw characters wearing jinyiwei-style hanfu.
Then again, the following pictures are of Ming emperors wearing yishanguan. These pictures are accurate for reference.
Animated version drawn by 燕王WF
There are some ancient paintings from the Song and Ming dynasties, on which people are wearing various kinds of wushamao.
The above is the brief introduction about yishanguan and wushamao, after that I will also introduce more other types of hanfu hats.
The Great Conjunction: Jupiter and Saturn 🌌.
the fact that jupiter and saturn haven’t been physically and observably this close since 1226 is so poetic bc you’re telling me i’m going to look up at and admire the same astronomical anomaly in the sky that someone hundreds and hundreds of years ago, with less knowledge of the stars and the planets than we have now, also looked up at and admired nonetheless. the past is long gone but the awareness of being connected to someone somewhere long ago thru the night sky is overwhelming me
Newly discovered Amazon rock art show the rainforest's earliest inhabitants living with giant Ice Age animals
Amazonian rock art newly discovered by researchers provides further proof the rainforest’s earliest inhabitants lived alongside now-extinct giant Ice Age animals.
The thousands of pictures are among the oldest depictions of people interacting with the huge creatures, including mastodons. Usually the only clues about their appearance are skeletal remains.
This is one of the largest collections of rock art found in South America. The recorded drawings, likely first made around 12,600 and 11,800 years ago, are on three rock shelters on hills in the Colombian Amazon. The paintings, identified during landscape surveys, also depict geometric shapes, human figures, and handprints, as well as hunting scenes and people interacting with plants, trees and savannah animals. The vibrant red pictures were produced over a period of hundreds, or possibly thousands, of years. Read more.
did humans invent math or did we discover it
does math even exist
So you know those mutant strains of radiotrophic fungus they discovered in Chernobyl? The ones that feed on gamma radiation? Those fungi, the radiation-eating fungi? From Chernobyl? They brought some on board the International Space Station and took some measurements. Here is the paper, titled:
A Self-Replicating Radiation-Shield for Human Deep-Space Exploration: Radiotrophic Fungi can Attenuate Ionizing Radiation aboard the International Space Station
Space is full of high-energy radiation, and radiation shielding is a big engineering challenge for Martian habitats and deep-space missions. What they figured out is that an 8-inch thick layer of mutant Chernobyl radiation-eating fungus in the walls of the spacecraft or habitat would serve as a self-replicating, self-sustaining radiation shield for long-haul missions.
This sounds like such a good and normal idea! Let’s do it!
Powehi means “the adorned fathomless dark creation” or “embellished dark source of unending creation” and comes from the Kumulipo, an 18th century Hawaiian creation chant. Po is a profound dark source of unending creation, while wehi, meaning honoured with embellishments, is one of the chant’s descriptions of po, the newspaper reported.
10 Amazing Space Discoveries by the World’s Largest Flying Observatory
On the night of May 26, 2010, the Stratospheric Observatory for Infrared Astronomy, or SOFIA, the world’s largest flying observatory, first peered into the cosmos. Its mission: to study celestial objects and astronomical phenomena with infrared light. Many objects in space emit almost all their energy at infrared wavelengths. Often, they are invisible when observed in ordinary, visible light. Over the last decade, the aircraft’s 106-inch telescope has been used to study black holes, planets, galaxies, star-forming nebulas and more! The observations have led to major breakthroughs in astronomy, revolutionizing our understanding of the solar system and beyond. To celebrate its 10 years of exploration, here’s a look at the top 10 discoveries made by our telescope on a plane:
The Universe’s First Type of Molecule
Scientists believe that around 100,000 years after the big bang, helium and hydrogen combined to make a molecule called helium hydride. Its recent discovery confirms a key part of our basic understanding of the early universe.
A New View of the Milky Way
More than a pretty picture, this panorama of cosmic scale reveals details that can help explain how massive stars are born and what’s feeding our Milky Way galaxy’s supermassive black hole.
When Planets Collide
A double-star system that is more than 300 light-years away likely had an extreme collision between two of its rocky planets. A similar event in our own solar system may have formed our Moon.
How A Black Hole Feasts
Fear not, the dark, my friend. And let the feast begin! Magnetic fields in the Cygnus A galaxy are trapping material where it is close enough to be devoured by a hungry black hole.
Somewhere Like Home
The planetary system around Epsilon Eridani, a star located about 10 light-years away, has an architecture remarkably similar to our solar system. What’s more, its central star is a younger, fainter version of our Sun.
A Quiet Place
Black holes in many galaxies are actively consuming material, but our Milky Way galaxy’s central black hole is relatively quiet. Observations show magnetic fields may be directing material around, not into, the belly of the beast.
The Great Escape
Ever wonder how material leaves a galaxy? The wind flowing from the center of the Cigar Galaxy is so strong it’s pulling a magnetic field — and the mass of 50 to 60 million Suns — with it.
Exploding Star, New Worlds
What happens when a star goes boom? It turns out that supernova explosions can produce a substantial amount of material from which planets like Earth can form.
Stellar Sibling Rivalry
They say siblings need time and space to grow, but here’s one that really needs some room. A newborn star in the Orion Nebula is clearing a bubble of space around it, preventing any new luminous family members from forming nearby.
Clues to Life’s Building Blocks
Radiation from stars is making organic molecules in nebula NGC 7023, also known as the Iris Nebula, larger and more complex. The growth of these molecules is one of the steps that could lead to the emergence of life under the right circumstances.
SOFIA is a modified Boeing 747SP aircraft that allows astronomers to study the solar system and beyond in ways that are not possible with ground-based telescopes. Find out more about the mission at www.nasa.gov/SOFIA.
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A Russian zoo is home to a unique animal - the liger. It is half-lioness, half-tiger. Mother Zita is pictured licking her one month old liliger cub
How do blackholes form and how do they move ?
Celebrate #BlackHoleFriday with Nurturing Baby Stars
Are you throwing all your money into a black hole today?
Forget Black Friday — celebrate #BlackHoleFriday with us and get sucked into this recent discovery of a black hole that may have sparked star births across multiple galaxies.
If confirmed, this discovery would represent the widest reach ever seen for a black hole acting as a stellar kick-starter — enhancing star formation more than one million light-years away. (One light year is equal to 6 trillion miles.)
A black hole is an extremely dense object from which no light can escape. The black hole’s immense gravity pulls in surrounding gas and dust. Sometimes, black holes hinder star birth. Sometimes — like perhaps in this case — they increase star birth.
Telescopes like our Chandra X-ray Observatory help us detect the X-rays produced by hot gas swirling around the black hole. Have more questions about black holes? Click here to learn more.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
Unveiling the Center of Our Milky Way Galaxy
We captured an extremely crisp infrared image of the center of our Milky Way galaxy. Spanning more than 600 light-years, this panorama reveals details within the dense swirls of gas and dust in high resolution, opening the door to future research into how massive stars are forming and what’s feeding the supermassive black hole at our galaxy’s core.
Among the features coming into focus are the jutting curves of the Arches Cluster containing the densest concentration of stars in our galaxy, as well as the Quintuplet Cluster with stars a million times brighter than our Sun. Our galaxy’s black hole takes shape with a glimpse of the fiery-looking ring of gas surrounding it.
The new view was made by the world’s largest airborne telescope, the Stratospheric Observatory for Infrared Astronomy, or SOFIA.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
Your fave is problematic: Neutron Stars
Neutron stars are probably one of the weirdest type of objects to exist in the universe… but first let me explain what a neutron star is
when a star with the mass of 8-20 times of the sun dies (and by dies I mean fucking explodes), the core collapses to form a neutron star
they are incredibly dense, spin rapidly and have very strong magnetic fields
sounds all fun and games, right? sounds normal? well listen up
So, we know that electrons usually refuse to be squeezed together. but in a death event of a big star, the pressure is so extreme that protons and electrons get violently SMASHED together and form neutrons.
sounds like someone needs to take an anti-agression class if you ask me
Now, what once was a star more massive than the Sun, is condensed to a tiny ball (usually about 10-20km!) of neutrons, with all of the mass in this tiny ball.
To visualize, imagine the mass of the Sun (300 000X the mass of the Earth), in a little 20km sphere, the size of a small city.
To visualize the density of a neutron star, think of the classic model of the atom. if an atom was a sports field 100m across, it would be mostly empty. almost all of the atom’s mass sits in the core, in this example, the core is the size of a marble.
but in a neutron star, this doesn’t apply anymore. in a neutron star, the entire stadium would be filled to the brim with neutrons. ALL. OF. IT.
a single cubic centimetre of Neutronium has the mass of 400 million tons. that’s the total mass of every single car and truck in the US.
the typical gravity of a neutron star is about 100 million times of that of the Earth. clingy as shit
so far, we have detected over 1000 of these weird fucks in our galaxy alone. yikes
some Neutron stars are vampires. They can be in a binary star system where a normal star orbits them and they feed of that material
summary: extremely weird and violent space ball of rage, tiny, filled to the top with anger, sometimes a vampire
Washington State University Physicists create 'negative mass'
Washington State University physicists have created a fluid with negative mass, which is exactly what it sounds like. Push it, and unlike every physical object in the world we know, it doesn’t accelerate in the direction it was pushed. It accelerates backwards.
The phenomenon is rarely created in laboratory conditions and can be used to explore some of the more challenging concepts of the cosmos, said Michael Forbes, a WSU assistant professor of physics and astronomy and an affiliate assistant professor at the University of Washington. The research appears today in the journal Physical Review Letters, where it is featured as an “Editor’s Suggestion.”
Hypothetically, matter can have negative mass in the same sense that an electric charge can be either negative or positive. People rarely think in these terms, and our everyday world sees only the positive aspects of Isaac Newton’s Second Law of Motion, in which a force is equal to the mass of an object times its acceleration, or F=ma. In other words, if you push an object, it will accelerate in the direction you’re pushing it. Mass will accelerate in the direction of the force.
Keep reading
10 Things Einstein Got Right
One hundred years ago, on May 29, 1919, astronomers observed a total solar eclipse in an ambitious effort to test Albert Einstein’s general theory of relativity by seeing it in action. Essentially, Einstein thought space and time were intertwined in an infinite “fabric,” like an outstretched blanket. A massive object such as the Sun bends the spacetime blanket with its gravity, such that light no longer travels in a straight line as it passes by the Sun.
This means the apparent positions of background stars seen close to the Sun in the sky – including during a solar eclipse – should seem slightly shifted in the absence of the Sun, because the Sun’s gravity bends light. But until the eclipse experiment, no one was able to test Einstein’s theory of general relativity, as no one could see stars near the Sun in the daytime otherwise.
The world celebrated the results of this eclipse experiment— a victory for Einstein, and the dawning of a new era of our understanding of the universe.
General relativity has many important consequences for what we see in the cosmos and how we make discoveries in deep space today. The same is true for Einstein’s slightly older theory, special relativity, with its widely celebrated equation E=mc². Here are 10 things that result from Einstein’s theories of relativity:
1. Universal Speed Limit
Einstein’s famous equation E=mc² contains “c,” the speed of light in a vacuum. Although light comes in many flavors – from the rainbow of colors humans can see to the radio waves that transmit spacecraft data – Einstein said all light must obey the speed limit of 186,000 miles (300,000 kilometers) per second. So, even if two particles of light carry very different amounts of energy, they will travel at the same speed.
This has been shown experimentally in space. In 2009, our Fermi Gamma-ray Space Telescope detected two photons at virtually the same moment, with one carrying a million times more energy than the other. They both came from a high-energy region near the collision of two neutron stars about 7 billion years ago. A neutron star is the highly dense remnant of a star that has exploded. While other theories posited that space-time itself has a “foamy” texture that might slow down more energetic particles, Fermi’s observations found in favor of Einstein.
2. Strong Lensing
Just like the Sun bends the light from distant stars that pass close to it, a massive object like a galaxy distorts the light from another object that is much farther away. In some cases, this phenomenon can actually help us unveil new galaxies. We say that the closer object acts like a “lens,” acting like a telescope that reveals the more distant object. Entire clusters of galaxies can be lensed and act as lenses, too.
When the lensing object appears close enough to the more distant object in the sky, we actually see multiple images of that faraway object. In 1979, scientists first observed a double image of a quasar, a very bright object at the center of a galaxy that involves a supermassive black hole feeding off a disk of inflowing gas. These apparent copies of the distant object change in brightness if the original object is changing, but not all at once, because of how space itself is bent by the foreground object’s gravity.
Sometimes, when a distant celestial object is precisely aligned with another object, we see light bent into an “Einstein ring” or arc. In this image from our Hubble Space Telescope, the sweeping arc of light represents a distant galaxy that has been lensed, forming a “smiley face” with other galaxies.
3. Weak Lensing
When a massive object acts as a lens for a farther object, but the objects are not specially aligned with respect to our view, only one image of the distant object is projected. This happens much more often. The closer object’s gravity makes the background object look larger and more stretched than it really is. This is called “weak lensing.”
Weak lensing is very important for studying some of the biggest mysteries of the universe: dark matter and dark energy. Dark matter is an invisible material that only interacts with regular matter through gravity, and holds together entire galaxies and groups of galaxies like a cosmic glue. Dark energy behaves like the opposite of gravity, making objects recede from each other. Three upcoming observatories – Our Wide Field Infrared Survey Telescope, WFIRST, mission, the European-led Euclid space mission with NASA participation, and the ground-based Large Synoptic Survey Telescope — will be key players in this effort. By surveying distortions of weakly lensed galaxies across the universe, scientists can characterize the effects of these persistently puzzling phenomena.
Gravitational lensing in general will also enable NASA’s James Webb Space telescope to look for some of the very first stars and galaxies of the universe.
4. Microlensing
So far, we’ve been talking about giant objects acting like magnifying lenses for other giant objects. But stars can also “lens” other stars, including stars that have planets around them. When light from a background star gets “lensed” by a closer star in the foreground, there is an increase in the background star’s brightness. If that foreground star also has a planet orbiting it, then telescopes can detect an extra bump in the background star’s light, caused by the orbiting planet. This technique for finding exoplanets, which are planets around stars other than our own, is called “microlensing.”
Our Spitzer Space Telescope, in collaboration with ground-based observatories, found an “iceball” planet through microlensing. While microlensing has so far found less than 100 confirmed planets, WFIRST could find more than 1,000 new exoplanets using this technique.
5. Black Holes
The very existence of black holes, extremely dense objects from which no light can escape, is a prediction of general relativity. They represent the most extreme distortions of the fabric of space-time, and are especially famous for how their immense gravity affects light in weird ways that only Einstein’s theory could explain.
In 2019 the Event Horizon Telescope international collaboration, supported by the National Science Foundation and other partners, unveiled the first image of a black hole’s event horizon, the border that defines a black hole’s “point of no return” for nearby material. NASA’s Chandra X-ray Observatory, Nuclear Spectroscopic Telescope Array (NuSTAR), Neil Gehrels Swift Observatory, and Fermi Gamma-ray Space Telescope all looked at the same black hole in a coordinated effort, and researchers are still analyzing the results.
6. Relativistic Jets
This Spitzer image shows the galaxy Messier 87 (M87) in infrared light, which has a supermassive black hole at its center. Around the black hole is a disk of extremely hot gas, as well as two jets of material shooting out in opposite directions. One of the jets, visible on the right of the image, is pointing almost exactly toward Earth. Its enhanced brightness is due to the emission of light from particles traveling toward the observer at near the speed of light, an effect called “relativistic beaming.” By contrast, the other jet is invisible at all wavelengths because it is traveling away from the observer near the speed of light. The details of how such jets work are still mysterious, and scientists will continue studying black holes for more clues.
7. A Gravitational Vortex
Speaking of black holes, their gravity is so intense that they make infalling material “wobble” around them. Like a spoon stirring honey, where honey is the space around a black hole, the black hole’s distortion of space has a wobbling effect on material orbiting the black hole. Until recently, this was only theoretical. But in 2016, an international team of scientists using European Space Agency’s XMM-Newton and our Nuclear Spectroscopic Telescope Array (NUSTAR) announced they had observed the signature of wobbling matter for the first time. Scientists will continue studying these odd effects of black holes to further probe Einstein’s ideas firsthand.
Incidentally, this wobbling of material around a black hole is similar to how Einstein explained Mercury’s odd orbit. As the closest planet to the Sun, Mercury feels the most gravitational tug from the Sun, and so its orbit’s orientation is slowly rotating around the Sun, creating a wobble.
8. Gravitational Waves
Ripples through space-time called gravitational waves were hypothesized by Einstein about 100 years ago, but not actually observed until recently. In 2016, an international collaboration of astronomers working with the Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors announced a landmark discovery: This enormous experiment detected the subtle signal of gravitational waves that had been traveling for 1.3 billion years after two black holes merged in a cataclysmic event. This opened a brand new door in an area of science called multi-messenger astronomy, in which both gravitational waves and light can be studied.
For example, our telescopes collaborated to measure light from two neutron stars merging after LIGO detected gravitational wave signals from the event, as announced in 2017. Given that gravitational waves from this event were detected mere 1.7 seconds before gamma rays from the merger, after both traveled 140 million light-years, scientists concluded Einstein was right about something else: gravitational waves and light waves travel at the same speed.
9. The Sun Delaying Radio Signals
Planetary exploration spacecraft have also shown Einstein to be right about general relativity. Because spacecraft communicate with Earth using light, in the form of radio waves, they present great opportunities to see whether the gravity of a massive object like the Sun changes light’s path.
In 1970, our Jet Propulsion Laboratory announced that Mariner VI and VII, which completed flybys of Mars in 1969, had conducted experiments using radio signals — and also agreed with Einstein. Using NASA’s Deep Space Network (DSN), the two Mariners took several hundred radio measurements for this purpose. Researchers measured the time it took for radio signals to travel from the DSN dish in Goldstone, California, to the spacecraft and back. As Einstein would have predicted, there was a delay in the total roundtrip time because of the Sun’s gravity. For Mariner VI, the maximum delay was 204 microseconds, which, while far less than a single second, aligned almost exactly with what Einstein’s theory would anticipate.
In 1979, the Viking landers performed an even more accurate experiment along these lines. Then, in 2003 a group of scientists used NASA’s Cassini Spacecraft to repeat these kinds of radio science experiments with 50 times greater precision than Viking. It’s clear that Einstein’s theory has held up!
10. Proof from Orbiting Earth
In 2004, we launched a spacecraft called Gravity Probe B specifically designed to watch Einstein’s theory play out in the orbit of Earth. The theory goes that Earth, a rotating body, should be pulling the fabric of space-time around it as it spins, in addition to distorting light with its gravity.
The spacecraft had four gyroscopes and pointed at the star IM Pegasi while orbiting Earth over the poles. In this experiment, if Einstein had been wrong, these gyroscopes would have always pointed in the same direction. But in 2011, scientists announced they had observed tiny changes in the gyroscopes’ directions as a consequence of Earth, because of its gravity, dragging space-time around it.
BONUS: Your GPS! Speaking of time delays, the GPS (global positioning system) on your phone or in your car relies on Einstein’s theories for accuracy. In order to know where you are, you need a receiver – like your phone, a ground station and a network of satellites orbiting Earth to send and receive signals. But according to general relativity, because of Earth’s gravity curving spacetime, satellites experience time moving slightly faster than on Earth. At the same time, special relativity would say time moves slower for objects that move much faster than others.
When scientists worked out the net effect of these forces, they found that the satellites’ clocks would always be a tiny bit ahead of clocks on Earth. While the difference per day is a matter of millionths of a second, that change really adds up. If GPS didn’t have relativity built into its technology, your phone would guide you miles out of your way!
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