If you live in the north and eastern part of the US, you’re probably experiencing some frigid weather. You’re probably also hearing people talk about something called a “polar vortex.”
Just what is a polar vortex and why is it making the temperatures so cold?
This image was captured by NOAA’s GOES-East satellite on Jan. 6, 2014, at 11:01 a.m. EST (1601 UTC). A frontal system that brought rain and snow to the US East coast is seen draped from north to south, and behind the front lies the clearer skies bitter cold air associated with the polar vortex. Also visible in the image is snow on the ground in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Michigan, Iowa and Missouri. The clouds over Texas are associated with a low pressure system centered over western Oklahoma that is part of the cold front connected to the movement of the polar vortex.
NASA explains that the polar vortex is a “whirling and persistent large area of low pressure, found typically over both North and South poles.”
Weather reports say the northern polar vortex was pushing southward over western Wisconsin and eastern Minnesota on Monday, Jan. 6, 2014, and was bringing frigid temperatures to half of the continental United States. It is expected to move northward back over Canada toward the end of the week.
More about the polar vortex:
Both the northern and southern polar vortexes are located in the middle and upper troposphere (lowest level of the atmosphere) and the stratosphere (next level up in the atmosphere). The polar vortex is a winter phenomenon. It develops and strengthens in its respective hemispheres’ winters as the sun sets over the polar region and temperatures cool. They weaken in the summer. In the Northern Hemisphere, they circulate in a counterclockwise direction, so the vortex sitting over western Wisconsin is sweeping in cold Arctic air around it.
You can find anything on the internet, right? A new study reveals, however, that you can’t find evidence of time travelers on the internet. Credible time travelers, that is.
The study was conducted by astrophysicist Robert Nemiroff who is part of the Astronomy Picture of the Day (APOD) team, along with some of his students from Michigan Technological University.
They did three separate types of searches, and developed a search strategy based on what they call “prescient knowledge.” They looked for discussions on social media and various websites where there might be evidence of a mention of something or someone before people should have known about it. If they were able to find evidence of that, it could indicate that whoever wrote it had traveled from the future.
They selected search terms relating to two recent phenomena, Pope Francis and Comet ISON, and began looking for references to them before they were known to exist.
First, they looked for specific terms on Twitter, then secondly looked for “prescient” inquiries submitted to a search engine, and the third search involved a request for a direct Internet communication, either by email or tweet, pre-dating to the time of the inquiry.
The team used a variety of search engines, such as Google and Bing, and combed through Facebook and Twitter.
“In our limited search we turned up nothing,” Nemiroff said in a press release. “I didn’t really think we would. But I’m still not aware of anyone undertaking a search like this. The Internet is essentially a vast database, and I thought that if time travelers were here, their existence would have already come out in some other way, maybe by posting winning lottery numbers before they were selected.”
So far, no lottery winners have confessed to using time travel to make their winnings.
In the case of Comet ISON, there were no mentions before it was discovered in September 2012. They discovered only one blog post referencing a Pope Francis before Jorge Mario Bergoglio was elected head of the Catholic Church on March 16, but it seemed more accidental than prescient.
In the third part of their search, the researchers created a post in September 2013 asking readers to email or tweet one of two messages on or before August 2013: “#ICanChangeThePast2” or “#ICannotChangeThePast2.”
Nemiroff and physics graduate student Teresa Wilson will present their findings today, Monday, Jan. 6, at the American Astronomical Society meeting in Washington, DC.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
As we’ve said before, all telescopes really want to be in space. In part 3 of our series on amateur telescope making, we bring you up to speed on the final frontier: amateurs building space telescopes. The hardware and software is available off the shelf, and launches have never been more affordable. The era of amateur space telescopes has arrived. Continue reading “Astronomy Cast Ep. 329: Telescope Making, Part 3: Space Telescopes”
Residents of high northern latitudes can take heart this frigid January: this coming weekend offers a chance to replicate a unique astronomical sighting.
Veteran sky watcher Bob King recently wrote a post for Universe Todaydescribing what observers can expect from the planet Venus for the last few weeks of this current evening apparition leading up to Venus’s passage between the Earth and the Sun on January 11th. Like so many other readers, we’ve been holding a nightly vigil to see when the last date will be that we can spot the fleeing world… and some great pics have been pouring in.
But did you know that when the conditions are just right, that you can actually spy Venus at the moment of inferior conjunction?
No, we’re not talking about a rare transit of Venus as last occurred on June 6th, 2012, when Venus crossed the disk of the Sun as seen from our Earthly perspective… you’ll have to wait until 2117 to see that occur again. What we’re talking about is a passage of Venus high above or below the solar disk, when spying it while the Sun sits just below the horizon might just be possible.
Not all inferior conjunctions of Venus are created equal. The planet’s orbit is tilted 3 degrees with respect to our own and can thus pass a maximum of eight degrees north or south of the Sun. Venus last did this on inferior conjunction in 2009 and will once again pass a maximum distance north of the Sun in 2017. For the southern hemisphere, the red letter years are 2007, and next year in 2015.
You’ll note that the above periods mark out an 8-year cycle, a period after which a roughly similar apparition of the planet Venus repeats. This is because Venus takes just over 224 days to complete one orbit, and 13 orbits of Venus very nearly equals 8 Earth years.
And while said northern maximum is still three years away, this week’s inferior conjunction is close at five degrees from the solar limb. The best prospects to see Venus at or near inferior conjunction occur for observers “North of the 60”. We accomplished this feat two Venusian 8-year cycles ago during the inferior conjunction of January 16th, 1998 from latitude 65 degrees north just outside of Fairbanks, Alaska. We set up on the Chena Flood Channel, assuring as low and as flat a horizon as possible… and we kept the engine of our trusty Jeep Wrangler idling as a refuge from the -40 degrees Celsius temperatures!
It took us several frigid minutes of sweeping the horizon with binoculars before we could pick up the dusky dot of Venus through the low atmospheric murk and pervasive ice fog. We could just glimpse Venus unaided afterward, once we knew exactly where to look!
This works because the ecliptic is at a relatively shallow enough angle to the horizon as seen from the high Arctic that Venus gets its maximum ~five degree “boost” above the horizon.
A word of warning is also in order not to attempt this sighting while the dazzling (and potentially eye damaging) Sun is above the horizon. Start sweeping the horizon for Venus about 30 minutes before local sunrise, with the limb of the Sun safely below the horizon.
Venus presents a disk 1’ 02” across as seen from Earth during inferior conjunction, the largest of any planet and the only one that can appear larger than an arc minute in size. Ironically, both Venus and Earth reach perihelion this month. Said disk is, however, only 0.4% illuminated and very near the theoretical edge of visibility known as the Danjon Limit. And although the technical visual magnitude of Venus at inferior conjunction is listed as -3.1, expect that illumination scattered across that razor thin crescent to be more like magnitude -0.6 due to atmospheric extinction.
Are you one of the +99% of the world’s citizens that doesn’t live in the high Arctic? You can still watch the passage of Venus from the relative warmth of your home online, via the Solar Heliospheric Observatory’s (SOHO) vantage point in space. SOHO sits at the sunward L1 point between the Earth and the Sun and has been monitoring Sol with a battery on instruments ever since its launch in 1995. A great side benefit of this is that SOHO also catches sight of planets and the occasional comet that strays near the Sun in its LASCO C2 and C3 cameras. Venus will begin entering the 15 degree wide field of view for SOHO’s LASCO C3 camera on January 7th, and you’ll be able to trace it all the way back out until January 14th.
From there on out, Venus will enter the early morning sky. When is the first date that you can catch it from your latitude with binoculars and /or the naked eye? Venus spends most of the remainder of 2014 in the dawn, reaching greatest elongation 46.6 degrees west of the Sun on March 22nd, 2014 and is headed back towards superior conjunction on the farside of the Sun on October 25th, 2014. But there’s lots more Venusian action in 2014 in store…. more to come!
We are awash in the unseen, the unknown and the unexplained. Our Universe is enshrouded in mystery. Even what we do know — the complex physical laws that describe the planets, stars and galaxies — can seem just beyond any normal human being’s grasp. We can’t all be Einsteins, after all.
But excluding string theory, dark energy and quantum field theory most of science is remarkably within our grasp. And in less than a minute, a concept as culturally conflicted and misunderstood as global warming, can be explained. See above.
The motivation behind this video is simple. Research shows that virtually no Americans — roughly 0 percent — can explain the physical mechanisms of global warming at even a basic level. So Berkeley Professor Michael Ranney and colleagues created a total of five videos (with the longest clocking in at 656 words in under five minutes) with the hope of elucidating the basics of global warming.
Their initial study, completed in 2011, surveyed 270 people in San Diego parks in order to assess how well the average American understands global warming. San Diego was chosen because it draws tourists from across the United States, and would thus create a better rounded sample.
“The main concept we were hoping people would tell us, which is at the heart of understanding global warming, is that there is an asymmetry between stuff that’s coming in to our planet and stuff that’s heading out,” Ranney told Universe Today.
This asymmetry explains why sunlight (in the form of visible light) may enter the atmosphere unhindered but is later impeded by greenhouse gases (because it is no longer in the form of visible light — it has been absorbed by the Earth and emitted in the form of infrared light). But not a single person could explain global warming at this basic level.
“We were shocked at how few people knew this” Ranney said. “I thought it was a moral imperative to get the word out as fast as possible.”
So Ranney and his colleagues set out with their work in front of them, creating the videos in order to increase the average American’s understanding of global warming. Their goal is that any one of the five videos will change the lives of seven billion viewers.
“We hope that a video of 400 words or even 35 words will allow people to have a moment in time to which they fix that they knew what the mechanism of climate change was,” Ranney told Universe Today. For that single moment “their knowledge was obvious, valid, understandable and available.”
In order to drive this point home, Ranney used an analogy that began like this: “So a climate change acceptor walks into a bar.” But all jokes aside, if one who accepts anthropogenic global warming tries to convince the man sitting next to him that global warming is real, but cannot explain the physical mechanism behind global warming, then he’s in trouble. He’s likely not only lost his bar mate but encouraged a life-time of global warming denial.
We cannot expect to increase the public’s awareness and acceptance of climate change without a huge increase in scientific literacy. Even if every viewer can’t recall the exact mechanistic details of global warming they can at least say to the man sitting next to them at the bar: “Look, I can’t regurgitate it now but I did understand it then.”
A second study provided college students with an explanation akin to the one found in the five-minute video. After reading it, the students not only understood global warming better but they were also more likely to accept global warming as a reality — suggesting these videos have the power to change people’s minds.
“Eventually people come to appreciate salient evidence,” Ranney told Universe Today. “Let’s say you think you’re in a fantastic monogamous relationship. If you come home and find your partner with someone else, it only takes that one moment in time to change your belief.”
Helping people to understand the basic physics behind global warming is a vital tool in convincing them that global warming is as real as it gets. Once someone clicks on the video, the next 52 seconds alone might leave a pretty big impact.
Ranney emphasized help from graduate student Lee Nevo Lamprey, undergraduate student Kimberly Le and other collaborators (including Dav Clark, Daniel Reinholz, Lloyd Goldwasser, Sarah Cohen and Rachel Ranney).
Once our own Sun has consumed all the hydrogen fuel in its core, it too will reach the end of its life. Astronomers estimate this to be a short 7 billion years from now. For a few million years, it will expand into a red giant, puffing away its outer layers. Then it’ll collapse down into a white dwarf and slowly cool down to the background temperature of the Universe.
I’m sure you know that some other stars explode when they die. They also run out of fuel in their core, but instead of becoming a red giant, they detonate in a fraction of a second as a supernova.
So, what’s the big difference between stars like our Sun and the stars that can explode as supernovae?
Mass. That’s it.
Supernova progenitors – these stars capable of becoming supernovae – are extremely massive, at least 8 to 12 times the mass of our Sun. When a star this big runs out of fuel, its core collapses. In a fraction of a second, material falls inward to creating an extremely dense neutron star or even a black hole. This process releases an enormous amount of energy, which we see as a supernova.
If a star has even more mass, beyond 140 times the mass of the Sun, it explodes completely and nothing remains at all. If these other stars can detonate like this, is it possible for our Sun to explode?
Could there be some chain reaction we could set off, some exotic element a rare comet could introduce on impact, or a science fiction doomsday ray we could fire up to make the Sun explode?
Nope, quite simply, it just doesn’t have enough mass. The only way this could ever happen is if it was much, much more massive, bringing it to that lower supernovae limit.
In other words, you would need to crash an equally massive star into our Sun. And then do it again, and again.. and again… another half dozen more times. Then, and only then would you have an object massive enough to detonate as a supernova.
Now, I’m sure you’re all resting easy knowing that solar detonation is near the bottom of the planetary annihilation list. I’ve got even better news. Not only will this never happen to the Sun, but there are no large stars close enough to cause us any damage if they did explode.
A supernova would need to go off within a distance of 100 light-years to irradiate our planet.
According to Dr. Phil Plait from Bad Astronomy, the closest star that could detonate as a supernova is the 10 solar mass Spica, at a distance of 260 light-years. No where near close enough to cause us any danger.
So don’t worry about our Sun exploding or another nearby star going supernova and wiping us out. You can put your feet up and relax, as it’s just not going to happen.
A Moment Frozen in Time
On May 19th, 2005, NASA’s Mars Exploration Rover Spirit captured this stunning view as the Sun sank below the rim of Gusev crater on Mars. This Panoramic Camera (Pancam) mosaic was taken around 6:07 in the evening of Sol 489. The terrain in the foreground is the rock outcrop “Jibsheet,” a feature that Spirit has been investigating for several weeks (rover tracks are dimly visible leading up to “Jibsheet”). The floor of Gusev crater is visible in the distance, and the Sun is setting behind the wall of Gusev some 80 km (50 miles) in the distance.
Credit: NASA/JPL-Caltech/Texas A&M/Cornell
See photo gallery below[/caption]
But a decade ago, NASA’s six wheeled Spirit rover was but a promise of great things to come. And her rich Martian scientific heritage we know today was but a dream yet to ensue
Jan. 3 marks the 10th anniversary since her touchdown on Mars on Jan. 3, 2004. Her twin sister Opportunity soft landed 3 weeks later on Jan. 24, 2004.
So here’s a collection of some of Spirit’s greatest hits on the Red Planet for all to enjoy and remember her fabulous exploits.
Read my detailed new overview marking ‘Spirits 10 Years on Mars’ – here – with even more spectacular Red Planet imagery!
Since the golf cart sized Spirit snapped over 128,000 raw images, drove 4.8 miles and ground into 15 rock targets we can’t show everything.
Here’s a retrospective of some of our favorites.
During her more than six year lifetime spanning until March 2010, Spirit discovered compelling evidence that ancient Mars exhibited hydrothermal activity, hot springs and volcanic explosions flowing with water.
“Spirit’s big scientific accomplishments are the silica deposits at Home Plate, the carbonates at Comanche, and all the evidence for hydrothermal systems and explosive volcanism, Rover Principal Investigator Steve Squyres of Cornell University, explained to me in an earlier interview.
“What we’ve learned is that early Mars at Spirit’s site was a hot, violent place, with hot springs, steam vents, and volcanic explosions. It was extraordinarily different from the Mars of today.”
Meanwhile, NASA’s new Curiosity rover just celebrated 500 Sols on Mars and is speeding towards Mount Sharp from inside Gale Crater – which is about the same size as Gusev crater.
Stay tuned here for Ken’s continuing Mars rover, Curiosity, Chang’e-3, SpaceX, Orbital Sciences, LADEE, MAVEN, MOM and more news.
Ten Years Ago, Spirit Rover Lands on Mars
This bird’s-eye view from August 2005 combines a self-portrait of the spacecraft deck and a panoramic mosaic of the Martian surface as viewed by NASA’s Mars Exploration Rover Spirit. The rover’s solar panels are still gleaming in the sunlight, having acquired only a thin veneer of dust two years after the rover landed and commenced exploring the red planet. Spirit captured this 360-degree panorama on the summit of “Husband Hill” inside Mars’ Gusev Crater. During the period from Spirit’s Martian days, or sols, 583 to 586 (Aug. 24 to 27, 2005), the rover’s panoramic camera acquired the hundreds of individual frames for this largest panorama ever photographed by Spirit. Credit: NASA/JPL-Caltech/Cornell
See Spirit’s 1st and last panoramas and more imagery below[/caption]
Today, Jan. 3, marks the 10th anniversary since the safe landing of NASA’s renowned Spirit rover on the plains of Mars on Jan. 3, 2004.
Spirit comprises one half of NASA’s now legendary pair of Mars Exploration Rovers (MER). Opportunity, her twin sister landed, on the opposite side of the Red Planet three weeks later – on Jan. 24, 2004. The goal was to “follow the water” as a potential enabler for past Martian microbes if they ever existed.
Together, the long-lived, golf cart sized robots proved that early Mars was warm and wet, billions of years ago – a key finding in the search for habitats conducive to life beyond Earth.
Exactly a decade ago, the famous robot survived the scorching atmospheric heating of the 6 minute plunge through the thin Martian atmosphere, bounced some two dozen times cocooned inside cushioning airbags, and gradually rolled to a stop inside 100 mile wide Gusev Crater. It was known as the “6 minutes of Terror”.
The three petaled landing pad opened and Spirit was dramatically born in a milestone event that will be forever remembered in the annuls of history because of the groundbreaking scientific discoveries that ensued and the unbelievable longevity of the twins.
Before they were launched atop Delta II rockets in the summer of 2003 from Cape Canaveral, the dynamic, solar powered robo duo were expected to last a mere three months – with a ‘warranty’ of 90 Martian days (Sols).
Either dust accumulation on the life giving solar panels, an engineering issue or the extremely harsh Martian environment was expected to somehow terminate them mercilessly.
In reality, both robots enormously exceeded expectations and accumulated a vast bonus time of exploration and discovery in numerous extended mission phases.
No one foresaw that Martian winds would occasionally clean the solar panels to give them a new lease on life or that the components would miraculously continue functioning.
Spirit endured the utterly extreme Red Planet climate for more than six years until communications ceased in 2010.
Opportunity is still roving Mars today, and doing so in rather good condition!
Altogether, Spirit drove 4.8 miles (7.73 kilometers),that’s about 12 times more than the original goal set for the mission.
She transmitted over 128,000 images.
After landing in the dusty plains, she headed for the nearby Columbia Hills some 2 miles away and ultimately became the first Martian mountaineer, when she scaled Husband Hill and found evidence for the flow of liquid water at the Hillary outcrop.
The rovers were not designed to climb hills. But eventually she scaled 30 degree inclines.
The rover was equipped with a rock grinder named the Rock Abrasion Tool (RAT) built by Honeybee Robotics.
Spirit ground the surfaces off 15 rock targets and scoured 92 targets with a brush to prepare the targets for inspection with spectrometers and a microscopic imager, according to NASA.
Eventually she drove back down the hill and made even greater scientific discoveries in the area known as ‘Home Plate’.
Spirit survived three harsh Martian winters and only succumbed to the Antarctic-like temperatures when she unexpectedly became mired in an unseen sand trap driving beside an ancient volcanic feature named ‘Home Plate’ that prevented the solar arrays from generating life giving power to safeguard critical electronic and computer components.
In 2007, Spirit made one of the key discoveries of the mission at ‘Home Plate’ when her stuck right front wheel churned up a trench of bright Martian soil that exposed a patch of nearly pure silica, which was formed in a watery hot spring or volcanic environment.
Spirit was heading towards another pair of volcanic objects named ‘von Braun’ and ‘Goddard’ and came within just a few hundred feet when she died in the sand trap.
See Spirits last panorama below – created from raw images taken in Feb. 2010 by Marco Di Lorenzo and Ken Kremer.
Here’s how the rovers’ principal investigator, Steve Squyres of Cornell University, Ithaca, N.Y., described some of the key findings in a NASA statement, starting with what Spirit found after driving from the crater floor where it landed into the Columbia hills to the east:
“In the Columbia Hills, we discovered compelling evidence of an ancient Mars that was a hot, wet, violent place, with volcanic explosions, hydrothermal activity, steam vents — nothing like Mars today.
“At Opportunity’s landing site, we found evidence of an early Mars that had acidic groundwater that sometimes reached the surface and evaporated away, leaving salts behind. It was an environment with liquid water, but very different from the environment that Spirit told us about.
“When Opportunity got to the rim of Endeavour Crater, we began a whole new mission. We found gypsum veins and a rich concentration of clay minerals. The clay minerals tell us about water chemistry that was neutral, instead of acidic — more favorable for microbial life, if any ever began on Mars.”
“Because of the rovers’ longevity, we essentially got four different landing sites for the price of two.”
Meanwhile, NASA’s new Curiosity rover just celebrated 500 Sols on Mars and is speeding towards Mount Sharp from inside Gale Crater – which is about the same size as Gusev crater.