Venus is often referred to as “Earth’s Twin” (or “sister planet”), and for good reason. Despite some rather glaring differences, not the least of which is their vastly different atmospheres, there are enough similarities between Earth and Venus that many scientists consider the two to be closely related. In short, they are believed to have been very similar early in their existence, but then evolved in different directions.
Earth and Venus are both terrestrial planets that are located within the Sun’s Habitable Zone (aka. “Goldilocks Zone”) and have similar sizes and compositions. Beyond that, however, they have little in common. Let’s go over all their characteristics, one by one, so we can in what ways they are different and what ways they are similar.
Electromagnetism is one of the fundamental forces of the universe, responsible for everything from electric and magnetic fields to light. Originally, scientists believed that magnetism and electricity were separate forces. But by the late 19th century, this view changed, as research demonstrated conclusively that positive and negative electrical charges were governed by one force (i.e. magnetism).
Since that time, scientists have sought to test and measure electromagnetic fields, and to recreate them. Towards this end, they created electromagnets, a device that uses electrical current to induce a magnetic field. And since their initial invention as a scientific instrument, electromagnets have gone on to become a regular feature of electronic devices and industrial processes.
In 1610, Galileo Galilei looked up at the night sky through a telescope of his own design. Spotting Jupiter, he noted the presence of several “luminous objects” surrounding it, which he initially took for stars. In time, he would notice that these “stars” were orbiting the planet, and realized that they were in fact Jupiter’s moons – which would come to be named Io, Europa, Ganymede and Callisto.
Of these, Ganymede is the largest, and boasts many fascinating characteristics. In addition to being the largest moon in the Solar System, it is also larger than even the planet Mercury. It is the only satellite in the Solar System known to possess a magnetosphere, has a thin oxygen atmosphere, and (much like its fellow-moons, Europa and Callisto) is believed to have an interior ocean.
From the vantage point of a window in an insane asylum, Vincent van Gogh painted one of the most noted and valued artistic works in human history. It was the summer of 1889. With his post-impressionist paint strokes, Starry Night depicts a night sky before sunrise that undulates, flows and is never settled. Scientific discoveries are revealing a Cosmos with such characteristics.
Since Vincent’s time, artists and scientists have taken their respective paths to convey and understand the natural world. The latest released images taken by the European Planck Space Telescope reveals new exquisite details of our Universe that begin to touch upon the paint strokes of the great master and at the same time looks back nearly to the beginning of time. Since Van Gogh – the passage of 125 years – scientists have constructed a progressively intricate and incredible description of the Universe.
The path from Van Gogh to the Planck Telescope imagery is indirect, an abstraction akin to the impressionism of van Gogh’s era. Impressionists in the 1800s showed us that the human mind could interpret and imagine the world beyond the limitations of our five senses. Furthermore, optics since the time of Galileo had begun to extend the capability of our senses.
Mathematics is perhaps the greatest form of abstraction of our vision of the World, the Cosmos. The path of science from the era of van Gogh began with his contemporary, James Clerk Maxwell who owes inspiration from the experimentalist Michael Faraday. The Maxwell equations mathematically define the nature of electricity and magnetism. Since Maxwell, electricity, magnetism and light have been intertwined. His equations are now a derivative of a more universal equation – the Standard Model of the Universe. The accompanying Universe Today article by Ramin Skibba describes in more detail the new findings by Planck Mission scientists and its impact on the Standard Model.
The work of Maxwell and experimentalists such as Faraday, Michelson and Morley built an overwhelming body of knowledge upon which Albert Einstein was able to write his papers of 1905, his miracle year (Annus mirabilis). His theories of the Universe have been interpreted, verified time and again and lead directly to the Universe studied by scientists employing the Planck Telescope.
In 1908, the German physicist Max Planck, for whom the ESA telescope is named, recognized the importance of Einstein’s work and finally invited him to Berlin and away from the obscurity of a patent office in Bern, Switzerland.
As Einstein spent a decade to complete his greatest work, the General Theory of Relativity, astronomers began to apply more powerful tools to their trade. Edwin Hubble, born in the year van Gogh painted Starry Night, began to observe the night sky with the most powerful telescope in the World, the Mt Wilson 100 inch Hooker Telescope. In the 1920s, Hubble discovered that the Milky Way was not the whole Universe but rather an island universe, one amongst billions of galaxies. His observations revealed that the Milky Way was a spiral galaxy of a form similar to neighboring galaxies, for example, M31, the Andromeda Galaxy.
Einstein’s equations and Picasso’s abstraction created another rush of discovery and expressionism that propel us for another 50 years. Their influence continues to impact our lives today.
Telescopes of Hubble’s era reached their peak with the Palomar 200 inch telescope, four times the light gathering power of Mount Wilson’s. Astronomy had to await the development of modern electronics. Improvements in photographic techniques would pale in comparison to what was to come.
The development of electronics was accelerated by the pressures placed upon opposing forces during World War II. Karl Jansky developed radio astronomy in the 1930s which benefited from research that followed during the war years. Jansky detected the radio signature of the Milky Way. As Maxwell and others imagined, astronomy began to expand beyond just visible light – into the infrared and radio waves. Discovery of the Cosmic Microwave Background (CMB) in 1964 by Arno Penzias and Robert Wilson is arguably the greatest discovery from observations in the radio wave (and microwave) region of the electromagnetic spectrum.
Analog electronics could augment photographic studies. Vacuum tubes led to photo-multiplier tubes that could count photons and measure more accurately the dynamics of stars and the spectral imagery of planets, nebulas and whole galaxies. Then in the 1947, three physicists at Bell Labs , John Bardeen, Walter Brattain, and William Shockley created the transistor that continues to transform the World today.
For astronomy and our image of the Universe, it meant more acute imagery of the Universe and imagery spanning across the whole electromagnetic spectrum. Infrared Astronomy developed slowly beginning in the 1800s but it was solid state electronics in the 1960s when it came of age. Microwave or Millimeter Radio Astronomy required a marriage of radio astronomy and solid state electronics. The first practical millimeter wave telescope began operations in 1980 at Kitt Peak Observatory.
With further improvements in solid state electronics and development of extremely accurate timing devices and development of low-temperature solid state electronics, astronomy has reached the present day. With modern rocketry, sensitive devices such as the Hubble and Planck Space Telescopes have been lofted into orbit and above the opaque atmosphere surrounding the Earth.
Astronomers and physicists now probe the Universe across the whole electromagnetic spectrum generating terabytes of data and abstractions of the raw data allow us to look out into the Universe with effectively a sixth sense, that which is given to us by 21st century technology. What a remarkable coincidence that the observations of our best telescopes peering through hundreds of thousands of light years, even more so, back 13.8 billion years to the beginning of time, reveal images of the Universe that are not unlike the brilliant and beautiful paintings of a human with a mind that gave him no choice but to see the world differently.
Now 125 years later, this sixth sense forces us to see the World in a similar light. Peer up into the sky and you can imagine the planetary systems revolving around nearly every star, swirling clouds of spiral galaxies, one even larger in the sky than our Moon, and waves of magnetic fields everywhere across the starry night.
Have you ever seen the beautiful auroral displays in the high latitudes? These are the Northern and Southern Lights. But what dark physics wizardry is going on to make this happen?
If you live in the high latitudes, like Alaska, or New Zealand, you’ve probably had a chance to see an aurora. Here in Canada, we call them the Northern Lights or the Aurora Borealis, but the lucky folks in the far southern latitudes see them too. On a good night, you can see flickering sheets of light that dance across the night sky, producing an amazing display of colors. You can see green, red and even yellow and purple ghostly displays.
So what causes the Northern Lights? They’re produced as our planet moves through the chemtrails emanating from the womp-rat sized exhaust ports of Planet X. Originating in the Bush-Cheney administration during a failed co-invasion attempt of the lizard people from the hollow part of the flat earth and aliens from John Carpenter’s THE THING. They cause diabetes, gluten sensitivity, itchy bun noodles and homeopathy and herald the coming of the Grand Nagus of MMA-UFC-ENTJ-LOL-WTF-BBQ. That is, if you believe everything you read on the internet.
Auroras are in fact caused by interactions between energetic particles from the Sun and the Earth’s magnetic field. The Earth is filled with liquid metal, and it rotates inside turning our planet into a giant magnet. Invisible magnetic field lines travel from the Earth’s northern magnetic pole to its southern magnetic pole. This is why compasses point north, they’re following the field lines produced by this giant metallic spinning goo core. Or as I like to call it “The Planetary Shield Generator”, which should not be confused with the giant whirling metallic debris field orbiting the Earth which is our “Alien Invasion Shield”. Which you can learn about in another episode.
So why would we need a Planetary Shield, you might ask? It is because we are perpetually under assault by our great enemy, the Sun. Our Sun is constantly releasing a flurry of energetic particles right at us. These particles are electrically charged and driven to Earth by the Solar Wind. When they encounter the Earth’s magnetic field, they’re forced into a spiral along the magnetic field lines. Eventually they collide with an oxygen or nitrogen atom in the Earth’s atmosphere and release photons of light.
So, thanks to the spinning magnet goo core, our planetary shield converts these particles into beautiful night time displays. Although there can be auroras almost any night in the highest latitudes, we see the most brilliant auroral displays after large flares on the Sun. The most powerful flares blast a hail of particles that’s so intense, auroral displays can be seen at mid and even low-latitudes. It sounds dangerous, but we’re perfectly safe here, beneath our protective atmosphere and magnetic field.
You might be amazed to know that auroral displays can even make sounds. People have reported crackling noises coming from the sky during an aurora. Even though the auroras themselves are at very high altitudes, the particle interactions can happen just a few hundred meters above the ground. People have reported hearing claps and crackles during an aurora, and this has been verified by microphones placed by scientists. If you could get high up into the atmosphere, I’m sure the sounds would be amazing.
The interactions between the Sun and our planet are just another gift we get from the night sky. If you’ve never seen an aurora with your own eyes, you really need to add them to your bucket list. Organize a trip to northern Europe or Alaska and get a chance to see this amazing display of nature.
Have you ever been lucky enough to see the Northern Lights? Tell us a story in the comments below.
It’s oft-repeated that black holes are powerful gravity wells, because they represent a dense concentration of matter in one location. But what about their magnetic fields? A new study suggests that this force could be at least as strong as gravity in supermassive black holes, the singularities that lurk in the center of many galaxies.
Simulations of magnetic fields of gas falling into these beasts suggest that this action — if the gas carries a magnetic field — makes the field stronger until it equals gravity.
Magnetic fields can affect properties such as how luminous black holes appear (in radio) and how powerful the jets emanating from the singularity are. The scientists speculate that when you see bright jets from a black hole, this could imply a strong magnetic field indeed.
“Surprisingly, the magnetic field strength around these exotic objects is comparable to the magnetic field produced in something more familiar: a magnetic resonance imaging (MRI) machine that you can find in your local hospital,” the Max Planck Institute for Radio Astronomy stated.
“Both supermassive black holes and MRI machines produce magnetic fields that are roughly 10,000 times stronger than the Earth’s surface magnetic field, which is what guides an ordinary compass.”
New information on how strong the magnetic fields was based on recent work with the Very Long Baseline Array, a networked group of radio telescopes in the United States. Specifically, the information came from a program named MOJAVE (Monitoring Of Jets in Active galactic nuclei with VLBA Experiments) that looks at jets around several hundred supermassive black holes.
The researchers emphasized that more observational research will be needed to supplement the simulations. The work will be published today in Nature. Leading the research was Mohammad Zamaninasab, a past researcher at Max Planck.
Expect the unexpected when it comes to northern lights. Last night beautifully illustrated nature’s penchant for surprise. A change in the “magnetic direction” of the wind of particles from the sun called the solar wind made all the difference. Minor chances for auroras blossomed into a spectacular, night-long storm for observers at mid-northern latitudes.
Packaged with the sun’s wind are portions of its magnetic field. As that material – called the interplanetary magnetic field (IMF) – sweeps past Earth, it normally glides by, deflected by our protective magnetic field, and we’re no worse for the wear. But when the solar magnetic field points south – called a southward Bz – it can cancel Earth’s northward-pointing field at the point of contact, opening a portal. Once linked, the IMF dumps high-speed particles into our atmosphere to light up the sky with northern lights.
Spiraling down magnetic field lines like firefighters on firepoles, billions of tiny solar electrons strike oxygen and nitrogen molecules in the thin air 60-125 miles up. When the excited atoms return back to their normal rest states, they shoot off niblets of green and red light that together wash the sky in multicolor arcs and rays. Early yesterday evening, the Bz plot in the ACE satellite data dipped sharply southward (above), setting the stage for a potential auroral display.
Nothing in the space weather forecast would have led you to believe northern lights were in the offing for mid-latitude skywatchers last night. Maybe a small possibility of a glow very low on the northern horizon. Instead we got the full-blown show. Nearly every form of aurora put in an appearance from multi-layered arcs spanning the northern sky to glowing red patches, crisp green rays and the bizarre flaming aurora. “Flames” look like waves or ripples of light rapidly fluttering from the bottom to the top of an auroral display. Absolutely unearthly in appearance and yet only 100 miles away.
VLF Auroral Chorus by Mark Dennison
I even broke out a hand-held VLF (very low frequency) radio and listened to the faint but crazy cosmic sounds of electrons diving through Earth’s magnetosphere. When my electron-jazzed brain finally hit the wall at 4 a.m., flames of moderately bright aurora still rippled across the north.
So what about tonight? Just like last night, there’s only a 5% chance of a minor storm. Take a look anyway – nature always has a surprise or two up her sleeve.
A satellite triplet was born last week. The European Space Agency’s Swarm constellation flew into space on Friday (Nov. 22) on a quest to understand more about the Earth’s magnetic field.
Around the same time, ESA put out a few videos explaining why the magnetic field is important. This one explains that the magnetic field has weakened over the past few years, while the north pole has shifted direction. “In fact, a whole pole reversal is possible,” the narrator says. “It happened last 780,000 years ago at the very beginning of human history. But cavemen didn’t have mobile phone networks, GPS networks or power supplies.”
If a reversal did happen, it could affect those systems, the video adds, asking “Will we soon find ourselves back in the stone age?”
In the short term, however, the focus is on Swarm’s science. The satellites successfully unfurled their booms on Saturday (Nov. 23) and are now starting three months of commissioning before their planned four-year mission.
Once they get going, the satellites will make observations from two altitudes — a pair at about 285 miles (460 kilometers) in altitude and the final of the trio at a higher altitude of 330 miles (530 kilometers). They will monitor any changes in the Earth’s magnetic field, looking at spots ranging from the core of our planet to areas of the upper atmosphere.
Nearly 18.7 billion kilometers from Earth — about 17 light-hours away — NASA’s Voyager 1 spacecraft is just about on the verge of entering interstellar space, a wild and unexplored territory of high-energy cosmic particles into which no human-made object has ever ventured. Launched in September 1977, Voyager 1 will soon become the first spacecraft to officially leave the Solar System.
Or has it already left?
I won’t pretend I haven’t heard it before: Voyager 1 has left the Solar System! Usually followed soon after by: um, no it hasn’t. And while it might all seem like an awful lot of flip-flopping by supposedly-respectable scientists, the reality is there’s not a clear boundary that defines the outer limits of our Solar System. It’s not as simple as Voyager rolling over a certain mileage, cruising past a planetary orbit, or breaking through some kind of discernible forcefield with a satisfying “pop.” (Although that would be cool.)
Rather, scientists look at Voyager’s data for evidence of a shift in the type of particles detected. Within the transitionary zone that the spacecraft has most recently been traveling through, low-energy particles from the Sun are outnumbered by higher-energy particles zipping through interstellar space, also called the local interstellar medium (LISM). Voyager’s instruments have been detecting dramatic shifts in the concentrations of each for over a year now, unmistakably trending toward the high-energy end — or at least showing a severe drop-off in solar particles — and researchers from the University of Maryland are claiming that this, along with their model of a porous solar magnetic field, indicates Voyager has broken on through to the other side.
“It’s a somewhat controversial view, but we think Voyager has finally left the Solar System, and is truly beginning its travels through the Milky Way,” said Marc Swisdak, UMD research scientist and lead author of a new paper published this week in The Astrophysical Journal Letters.
According to Swisdak, fellow UMD plasma physicist James F. Drake, and Merav Opher of Boston University, their model of the outer edge of the Solar System fits recent Voyager 1 observations — both expected and unexpected. In fact, the UMD-led team says that Voyager passed the outer boundary of the Sun’s magnetic influence, aka the heliopause… last year.
But, like some of last year’s claims, these conclusions aren’t shared by mission scientists at NASA.
“Details of a new model have just been published that lead the scientists who created the model to argue that NASA’s Voyager 1 spacecraft data can be consistent with entering interstellar space in 2012,” said Ed Stone, Voyager project scientist at Caltech, in a press release issued today. “In describing on a fine scale how magnetic field lines from the sun and magnetic field lines from interstellar space can connect to each other, they conclude Voyager 1 has been detecting the interstellar magnetic field since July 27, 2012. Their model would mean that the interstellar magnetic field direction is the same as that which originates from our sun.
“Other models envision the interstellar magnetic field draped around our solar bubble and predict that the direction of the interstellar magnetic field is different from the solar magnetic field inside. By that interpretation, Voyager 1 would still be inside our solar bubble.”
Stone says that further discussion and investigation will be needed to “reconcile what may be happening on a fine scale with what happens on a larger scale.”
Whether still within the Solar System — however it’s defined — or outside of it, the bottom line is that the venerable Voyager spacecraft are still conducting groundbreaking research of our cosmic neighborhood, 36 years after their respective launches and long after their last views of the planets. And that’s something nobody can argue about.
“The Voyager 1 spacecraft is exploring a region no spacecraft has ever been to before. We will continue to look for any further developments over the coming months and years as Voyager explores an uncharted frontier.”
– Ed Stone, Voyager project scientist
Built by JPL and launched in 1977, both Voyagers are still capable of returning scientific data from a full range of instruments, with adequate power and propellant to remain operating until 2020.
Note: The definition of “Solar System” used in this article is in reference to the Sun’s magnetic influence, the heliosphere, and all that falls within its outermost boundary, the heliopause (wherever that is.) Objects farther out are still gravitationally held by the Sun, such as distant KBOs and Oort Cloud comets, but orbit within the interstellar medium.
Gather round the internets for another episode of the Weekly Space Hangout. Where our experienced team of journalists, astronomers and astronomer-journalists bring you up to speed on the big happenings in the universe of space and astronomy.
Our team this week:
Reporters: Casey Dreier, David Dickinson, Amy Shira Teitel, Sondy Springmann, Nicole Gugliuci
We record the Weekly Space Hangout every Friday at Noon Pacific, 3 pm Eastern. Join us live here on Universe Today, over on our YouTube account, or on Google+. Or you can watch the archive after the fact.