Asteroid 2014 YB35 will safely pass Earth at 4.5 million km on Friday, March 27. (Composite image by J. Major showing asteroid Lutetia imaged by ESA's Rosetta, Earth and Moon imaged by NASA's Galileo, and the Milky Way imaged by ESO and Serge Brunier.)
There are ways to report on occasional close approaches by near-Earth objects (NEOs) that convey the respectful awareness of their presences and the fact that our planet shares its neighborhood with many other objects, large and small… and that sometimes their paths around the Sun bring them unnervingly close to our own.
Then there’s just straight-up over-sensationalism intended to drum up page views by scaring the heck out of people, regardless of facts.
Apparently this is what’s happened regarding the upcoming close approach by NEO 2014 YB35. An asteroid of considerable (but definitely not unprecedented) size – estimated 440-990 meters in diameter, or around a third of a mile across – YB35 will pass by Earth on Friday, March 27, coming as close as 11.7 times the distance between Earth and the Moon at 06:20 UTC.
11.7 lunar distances. That’s 4.5 million kilometers, or almost 2.8 million miles. Cosmically close, sure, but far from “skimming”…and certainly with no danger of an impact or any of the nasty effects that would be a result thereof. None. Zero. Zilch. NASA isn’t concerned, and you shouldn’t be either.
I typically wouldn’t even bother writing up something like this, except that I have been seeing posts shared among acquaintances on Facebook and Twitter that refer to sensationalist articles portraying the event as a frightening near-miss by an apocalyptic object. I won’t link to those articles here but in short they focus heavily on the destructive nature of an object the size of YB35 were it to hit Earth and how it would wipe out “all species” of life on our planet wholesale, and how YB35 is “on course” with Earth’s orbit.
The problem I have is that these statements, although technically not false in themselves, are not being used to demonstrate the potential danger of large-scale cosmic impact events but rather to frighten and alarm people about this particular pass. Which is not any way to responsibly inform the public about impacts, asteroids, and what we can or should be doing to mitigate these dangers.
Orbital diagram of 2014 YB35 for March 27, 2015. Via JPL’s Small-Body Database.
First observed through the Catalina Sky Survey in Dec. 2014, YB35 is a good-sized asteroid. It will come relatively close to Earth on Friday but more than plenty far enough away to not pose any danger or have any physical effects on Earth in any way (similar to the close pass of the smaller asteroid 2014 UR116 in December.) YB35 will actually make slightly closer passes in March 2033 and in 2128, but still at similar distances.
YB35 is, for all intents and purposes, one of the many potentially-hazardous* asteroids that won’t hit us, and NASA is well aware of nearly all of the NEOs in its size range thanks in no small part to space observatories like NEOWISE and various ground-based survey projects around the world. They will observe this event for the increased information on YB35 that can be gathered, but they are not “on alert” and the astronomers certainly aren’t “terrified.”
Should we take this as a reminder that large asteroids are out there and we should be as diligent as we can about identifying them? Yes, certainly. Should we support missions that would help spot and track near-Earth objects as well as those that would provide a way to potentially deflect any large incoming ones? Of course. Should we drop to our knees and cry “why?!” or sleep in our backyard bunkers tonight surrounded by bottled water and cans of beans? Not at all.
So don’t believe the hype, don’t go max out your credit cards, and please don’t sleep in your bunker. Pass it on.
Want to learn more about NEOs and close approaches? Visit JPL’s Near-Earth Object Program page here. Also, watch a fascinating animation showing the discovery rate of asteroids in the Solar System from 1980-2011 by Scott Manley below.
*Note: Potentially-hazardous asteroids (PHAs) are those larger than 150m whose orbits could cross Earth’s in the future, not necessarily that they will or that Earth will be sharing the same place when and if they do.
A view of the Villarrica Volcano's Eruption In Chile on March 3, 2-15. Credit: Ariel Marinkovic/EPA /Landov.
Want some volcano facts? Here are 10 interesting facts about volcanoes. Some of these facts you’ll know, and others may surprise you. Whatever the case, volcanoes are amazing features of nature that demand our respect.
1. There are Three Major Kinds of Volcanoes:
Although volcanoes are all made from hot magma reaching the surface of the Earth and erupting, there are different kinds. Shield volcanoes have lava flows with low viscosity that flow dozens of kilometers; this makes them very wide with smoothly sloping flanks.
Stratovolcanoes are made up of different kinds of lava, and eruptions of ash and rock and grow to enormous heights. Cinder cone volcanoes are usually smaller, and come from short-lived eruptions that only make a cone about 400 meters high.
2. Volcanoes Erupt Because of Escaping Magma:
About 30 km beneath your feet is the Earth’s mantle. It’s a region of superhot rock that extends down to the Earth’s core. This region is so hot that molten rock can squeeze out and form giant bubbles of liquid rock called magma chambers. This magma is lighter than the surrounding rock, so it rises up, finding cracks and weakness in the Earth’s crust.
Lava fountain in Hawaii. Image Credit: Jim D. Griggs/HVO/USGS
When it finally reaches the surface, it erupts out of the ground as lava, ash, volcanic gasses and rock. It’s called magma when it’s under the ground, and lava when it erupts onto the surface.
3. Volcanoes can be Active, Dormant or Extinct:
An active volcano is one that has had an eruption in historical times (in the last few thousand years). A dormant volcano is one that has erupted in historical times and has the potential to erupt again, it just hasn’t erupted recently. An extinct volcano is one that scientists think probably won’t erupt again. Here’s more information on the active volcanoes in the world.
4. Volcanoes can Grow Quickly:
Although some volcanoes can take thousands of years to form, others can grow overnight. For example, the cinder cone volcano Paricutin appeared in a Mexican cornfield on February 20, 1943. Within a week it was 5 stories tall, and by the end of a year it had grown to more than 336 meters tall. It ended its grown in 1952, at a height of 424 meters. By geology standards, that’s pretty quick.
Detailed view from space of the ash plume caused by the Eyjafjallajökull volcano in 2010. Credit: NASA
5. There are 20 Volcanoes Erupting Right Now:
Somewhere, around the world, there are likely about 20 active volcanoes erupting as you’re reading this. Some are experiencing new activity, others are ongoing. Between 50-70 volcanoes erupted last year, and 160 were active in the last decade. Geologists estimate that 1,300 erupted in the last 10,000 years.
Three quarters of all eruptions happen underneath the ocean, and most are actively erupting and no geologist knows about it at all. One of the reasons is that volcanoes occur at the mid ocean ridges, where the ocean’s plates are spreading apart. If you add the underwater volcanoes, you get an estimate that there are a total of about 6,000 volcanoes that have erupted in the last 10,000 years.
6. Volcanoes are Dangerous:
But then you knew that. Some of the most deadly volcanoes include Krakatoa, which erupted in 1883, releasing a tsunami that killed 36,000 people. When Vesuvius exploded in AD 79, it buried the towns of Pompeii and Herculaneum, killing 16,000 people.
Image of Mt. Vesuvius, captured in 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard the Terra satellite. Credit: NASA/EO
Mount Pelee, on the island of Martinique destroyed a town with 30,000 people in 1902. The most dangerous aspect of volcanoes are the deadly pyroclastic flows that blast down the side of a volcano during an eruption. These contain ash, rock and water moving hundreds of kilometers an hour, and hotter than 1,000 degrees C.
7. Supervolcanoes are Really Dangerous:
Geologists measure volcano eruptions using the Volcano Explosivity Index, which measures the amount of material released. A “small” eruption like Mount St. Helens was a 5 out of 8, releasing a cubic kilometer of material. The largest explosion on record was Toba, thought to have erupted 73,000 years ago.
It released more than 1,000 cubic kilometers of material, and created a caldera 100 km long and 30 kilometers wide. The explosion plunged the world into a world wide ice age. Toba was considered an 8 on the VEI.
8. The Tallest Volcano in the Solar System isn’t on Earth:
That’s right, the tallest volcano in the Solar System isn’t on Earth at all, but on Mars. Olympus Mons, on Mars, is a giant shield volcano that rises to an elevation of 27 km, and it measures 550 km across. Scientists think that Olympus Mons was able to get so large because there aren’t any plate tectonics on Mars. A single hotspot was able to bubble away for billions of years, building the volcano up bigger and bigger.
Mauna Kea observed from space. Credit: NASA/EO
9. The Tallest and Biggest Volcanoes on Earth are side by side:
The tallest volcano on Earth is Hawaii’s Mauna Kea, with an elevation of 4,207 meters. It’s only a little bigger than the largest volcano on Earth, Mauna Loa with an elevation of only 4,169 meters. Both are shield volcanoes that rise up from the bottom of the ocean. If you could measure Mauna Kea from the base of the ocean to its peak, you’d get a true height of 10,203 meters (and that’s bigger than Mount Everest).
10. The Most Distant Point from the Center of the Earth is a Volcano:
You might think that the peak of Mount Everest is the most distant point from the center of the Earth, but that’s not true. Instead, it’s the volcano Chimborazo in Ecuador. That’s because the Earth is spinning in space and is flattened out. Points at the equator are further from the center of the Earth than the poles. And Chimborazo is very close to the Earth’s equator.
I for one have never witnessed the northern lights in person, and like many people I experience them vicariously through the photography and videos of more well-traveled (or more polar-bound) individuals. Typically these are either single-shot photos or time-lapses made up of many somewhat long-exposure images. As beautiful as these are, they don’t accurately capture the true motion of this upper atmospheric phenomenon. But here we get a look at the aurora as it looks in real time, captured on camera by Jon Kerr from northern Finland. Check it out above or watch in full screen HD on YouTube.
The video was shot with a full-frame mirrorless Sony a7S. See more of Jon’s aurora videos on YouTube here.
Technicians work on NASA’s 20-foot-tall Magnetospheric Multiscale (MMS) mated quartet of stacked observatories in the cleanroom at NASA's Goddard Space Flight Center in Greenbelt, Md., on May 12, 2014. Credit: Ken Kremer- kenkremer.com
NASA’s first mission dedicated to study the process in nature known as magnetic reconnection undergoing final preparation for launch from Cape Canaveral, Florida in just under two weeks time.
The Magnetospheric Multiscale (MMS) mission is comprised of a quartet of identically instrumented observatories aimed at providing the first three-dimensional views of a fundamental process in nature known as magnetic reconnection.
Magnetic reconnection is the process whereby magnetic fields around Earth connect and disconnect while explosively releasing vast amounts of energy. It occurs throughout the universe.
“Magnetic reconnection is one of the most important drivers of space weather events,” said Jeff Newmark, interim director of the Heliophysics Division at NASA Headquarters in Washington.
“Eruptive solar flares, coronal mass ejections, and geomagnetic storms all involve the release, through reconnection, of energy stored in magnetic fields. Space weather events can affect modern technological systems such as communications networks, GPS navigation, and electrical power grids.”
The four MMS have been stacked on top of one another like pancakes, encapsulated in the payload fairing, transported to the launch pad, hoisted and mated to the top of the 195-foot-tall rocket.
NASA’s Magnetospheric Multiscale (MMS) observatories are shown here in the clean room being processed for a March 12, 2015 launch from Space Launch Complex 41 on Cape Canaveral Air Force Station, Florida. Credit: NASA/Ben Smegelsky
The nighttime launch of MMS on a United Launch Alliance Atlas V rocket should put on a spectacular sky show for local spectators along the Florida space coast as well as more distant located arcing out in all directions.
Liftoff is slated for 10:44 p.m. EDT Thursday March 12 from Space Launch Complex 41 on Cape Canaveral Air Force Station, Florida.
The launch window extends for 30 minutes.
Artist rendition of the four MMS spacecraft in orbit in Earth’s magnetic field. Credit: NASA
After a six month check out phase the probes will start science operation in September.
Unlike previous missions to observe the evidence of magnetic reconnection events, MMS will have sufficient resolution to measure the characteristics of ongoing reconnection events as they occur.
The four probes were built in-house by NASA at the agency’s Goddard Space Flight Center in Greenbelt, Maryland where is visited them during an inspection tour by NASA Administrator Charles Bolden.
I asked Bolden to explain the goals of MMS during a one-on-one interview.
“MMS will help us study the phenomena known as magnetic reconnection and help us understand how energy from the sun – magnetic and otherwise – affects our own life here on Earth,” Bolden told Universe Today.
“MMS will study what effects that process … and how the magnetosphere protects Earth.”
MMS measurements should lead to significant improvements in models for yielding better predictions of space weather and thereby the resulting impacts for life here on Earth as well as for humans aboard the ISS and robotic satellite explorers in orbit and the heavens beyond.
NASA Administrator Charles Bolden poses with the agency’s Magnetospheric Multiscale (MMS) spacecraft, mission personnel, Goddard Center Director Chris Scolese and NASA Associate Administrator John Grunsfeld, during visit to the cleanroom at NASA’s Goddard Space Flight Center in Greenbelt, Md., on May 12, 2014. Credit: Ken Kremer- kenkremer.com
The best place to study magnetic reconnection is ‘in situ’ in Earth’s magnetosphere. This will lead to better predictions of space weather phenomena.
“This is the perfect time for this mission,” said Jim Burch, principal investigator of the MMS instrument suite science team at Southwest Research Institute (SwRI) in San Antonio, Texas.
“MMS is a crucial next step in advancing the science of magnetic reconnection. Studying magnetic reconnection near Earth will unlock the ability to understand how this process works throughout the entire universe.”
Magnetic reconnection is also believed to help trigger the spectacular aurora known as the Northern or Southern lights.
MMS is a Solar Terrestrial Probes Program, or STP, mission within NASA’s Heliophysics Division.
Watch for Ken’s ongoing MMS coverage and he’ll be onsite at the Kennedy Space Center in the days leading up to the launch on March 12.
Stay tuned here for Ken’s continuing MMS, Earth and planetary science and human spaceflight news.
Ken Kremer
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Learn more about MMS, Mars rovers, Orion, SpaceX, Antares, NASA missions and more at Ken’s upcoming outreach events:
Mar 6: “MMS Update, Future of NASA Human Spaceflight, Curiosity on Mars,” Delaware Valley Astronomers Assoc (DVAA), Radnor, PA, 7 PM.
Mar 10-12: “MMS, Orion, SpaceX, Antares, Curiosity Explores Mars,” Kennedy Space Center Quality Inn, Titusville, FL, evenings
The Academy Award winning film “Birdman” used what’s called tracking shot to create the sense of a seamless one-shot film. A new timelapse created from imagery captured by astronauts on the International Space Station uses the same technique — which has not been used in previous ISS timelapses — with stunning results. Additionally, the footage is very recent, from January and February 2015. It was compiled by Phil Selmes.
“The footage has been composited and edited to show enhanced camera movement, a day to night transition, and an uninterrupted camera movement which links two timelapse shots seamlessly,” Selmes told Universe Today. “These processes have never been used to present ISS time lapse footage in this way before.” Continue reading “Incredible “Birdman”-like Tracking-Shot Timelapse of Earth from Space”
If you’ve read your share of sci-fi, and I know you have, you’ve read stories about another Earth-sized planet orbiting on the other side of the Solar System, blocked by the Sun. Could it really be there?
No. Nooooo. No. Just no.
This is a delightful staple in science fiction. There’s a mysterious world that orbits the Sun exactly the same distance as Earth, but it’s directly across the Solar System from us; always hidden by the Sun. Little do we realize they know we’re here, and right now they’re marshalling their attack fleet to invade our planet. We need to invade counter-Earth before they attack us and steal our water, eat all our cheese or kidnap our beloved Nigella Lawson and Alton Brown to rule as their culinary queen and king of Other-Earth.
Well, could this happen? Could there be another planet in a stable orbit, hiding behind the Sun? The answer, as you probably suspect, is NO. No. Nooooo. Just no.
Well, that’s not completely true. If some powerful and mysterious flying spaghetti being magically created another planet and threw it into orbit, it would briefly be hidden from our view because of the Sun. But we don’t exist in a Solar System with just the Sun and the Earth. There are those other planets orbiting the Sun as well. As the Earth orbits the Sun, it’s subtly influenced by those other planets, speeding up or slowing down in its orbit.
So, while we’re being pulled a little forwards in our orbit by Jupiter, that other planet would be on the opposite side of the Sun. And so, we’d speed up a little and catch sight of it around the Sun. Over the years, these various motions would escalate, and that other planet would be seen more and more in the sky as we catch up to it in orbit.
Eventually, our orbits would intersect, and there’d be an encounter. If we were lucky, the planets would miss each other, and be kicked into new, safer, more stable orbits around the Sun. And if we were unlucky, they’d collide with each other, forming a new super-sized Earth, killing everything on both planets, obviously.
Diagram of the five Lagrange points associated with the sun-Earth system, showing DSCOVR orbiting the L-1 point. Image is not to scale. Credit: NASA/WMAP Science Team
What if there was originally two half-Earths and they collided and that’s how we got current Earth! Or 4 quarter Earths, each with their own population? And then BAM. One big Earth. Or maybe 64 64th Earths all transforming and converging to form VOLTREARTH.
Now, I’m now going to make things worse, and feed your imagination a little with some actual science. There are a few places where objects can share a stable orbit. These locations are known as Lagrange points, regions where the gravity of two objects create a stable location for a third object. The best of these are known as the L4 and L5 Lagrangian points. L4 is about 60-degrees ahead of a planet in its orbit, and L5 is about 60-degrees behind a planet in its orbit.
A small enough body, relative to the planet, could hang out in a stable location for billions of years. Jupiter has a collection of Trojan asteroids at its L4 and L5 points of its orbit, always holding at a stable distance from the planet. Which means, if you had a massive enough gas giant, you could have a less massive terrestrial world in a stable orbit 60-degrees away from the planet.
Grumpy Cat has the correct answer. Credit: grumpycat.com
Well, it was a pretty clever idea. Unfortunately, the forces of gravity conspire to make this hidden planet idea completely impossible. Most importantly, when someone tells you there’s a hidden planet on the other side of the Sun, just remember these words:
No.
Nooooo.
No.
Go ahead and name your favorite sci-fi stories that have used this trope. Tell us in the comments below.
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These six narrow-angle color images were made from the first ever "portrait" of the solar system taken by Voyager 1 on Valentine’s Day on Feb. 14, 1990, which was more than 4 billion miles from Earth and about 32 degrees above the ecliptic. Venus, Earth, Jupiter, and Saturn, Uranus, Neptune are seen in these blown-up images, from left to right and top to bottom. Credit: NASA/JPL-Caltech
A quarter of a century has passed since NASA’s Voyager 1 spacecraft snapped the iconic image of Earth known as the “Pale Blue Dot” that shows all of humanity as merely a tiny point of light.
The outward bound Voyager 1 space probe took the ‘pale blue dot’ image of Earth 25 years ago on Valentine’s Day, on Feb. 14, 1990 when it looked back from its unique perch beyond the orbit of Neptune to capture the first ever “portrait” of the solar system from its outer realms.
Voyager 1 was 4 billion miles from Earth, 40 astronomical units (AU) from the sun and about 32 degrees above the ecliptic at that moment.
The idea for the images came from the world famous astronomer Carl Sagan, who was a member of the Voyager imaging team at the time.
He head the idea of pointing the spacecraft back toward its home for a last look as a way to inspire humanity. And to do so before the imaging system was shut down permanently thereafter to repurpose the computer controlling it, save on energy consumption and extend the probes lifetime, because it was so far away from any celestial objects.
Sagan later published a well known and regarded book in 1994 titled “Pale Blue Dot,” that refers to the image of Earth in Voyagers series.
This narrow-angle color image of the Earth, dubbed “Pale Blue Dot,” is a part of the first ever “portrait” of the solar system taken by Voyager 1 on Valentine’s Day on Feb. 14, 1990. Credit: NASA/JPL-Caltech
“Twenty-five years ago, Voyager 1 looked back toward Earth and saw a ‘pale blue dot,’ ” an image that continues to inspire wonderment about the spot we call home,” said Ed Stone, project scientist for the Voyager mission, based at the California Institute of Technology, Pasadena, in a statement.
Six of the Solar System’s nine known planets at the time were imaged, including Venus, Earth, Jupiter, and Saturn, Uranus, Neptune. The other three didn’t make it in. Mercury was too close to the sun, Mars had too little sunlight and little Pluto was too dim.
Voyager snapped a series of images with its wide angle and narrow angle cameras. Altogether 60 images from the wide angle camera were compiled into the first “solar system mosaic.”
Voyager 1 was launched in 1977 from Cape Canaveral Air Force Station in Florida as part of a twin probe series with Voyager 2. They successfully conducted up close flyby observations of the gas giant outer planets including Jupiter, Saturn, Uranus and Neptune in the 1970s and 1980s.
Both probes still operate today as part of the Voyager Interstellar Mission.
“After taking these images in 1990, we began our interstellar mission. We had no idea how long the spacecraft would last,” Stone said.
Hurtling along at a distance of 130 astronomical units from the sun, Voyager 1 is the farthest human-made object from Earth.
Solar System Portrait – 60 Frame Mosaic. The cameras of Voyager 1 on Feb. 14, 1990, pointed back toward the sun and took a series of pictures of the sun and the planets, making the first ever “portrait” of our solar system as seen from the outside. Missing are Mercury, Mars and Pluto. Credit: NASA/JPL-Caltech
Voyager 1 still operates today as the first human made instrument to reach interstellar space and continues to forge new frontiers outwards to the unexplored cosmos where no human or robotic emissary as gone before.
Here’s what Sagan wrote in his “Pale Blue Dot” book:
“That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. … There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
A full Moon flyby, as seen from Paris, France. Credit and copyright: Sebastien Lebrigand.
Shining like a beacon in Earth’s sky is the Moon. We’ve seen so much of it in our lifetimes that it’s easy to take it for granted; even the human landings on the Moon in the 1960s and 1970s were eventually taken for granted by the public.
Fortunately for science, we haven’t stopped looking at the Moon in the decades after Neil Armstrong took his first step. Here are a few things to consider about Earth’s closest big neighbor.
A montage of planets and other objects in the solar system. Credit: NASA/JPL
While the universe is a big place to study, we shouldn’t forget our own backyard. With eight planets and a wealth of smaller worlds to look at, there’s more than enough to learn for a few lifetimes!
So what are some of the most surprising things about the planets? We’ve highlighted a few things below.
1. Mercury is hot, but not too hot for ice
The closest planet to the Sun does indeed have ice on its surface. That sounds surprising at first glance, but the ice is found in permanently shadowed craters — those that never receive any sunlight. It is thought that perhaps comets delivered this ice to Mercury in the first place. In fact, NASA’s MESSENGER spacecraft not only found ice at the north pole, but it also found organics, which are the building blocks for life. Mercury is way too hot and airless for life as we know it, but it shows how these elements are distributed across the Solar System.
2. Venus doesn’t have any moons, and we aren’t sure why.
Both Mercury and Venus have no moons, which can be considered a surprise given there are dozens of other ones around the Solar System. Saturn has over 60, for example. And some moons are little more than captured asteroids, which may have been what happened with Mars’ two moons, for example. So what makes these planets different? No one is really sure why Venus doesn’t, but there is at least one stream of research that suggests it could have had one in the past.
Mars, as it appears today, Credit: NASA
3. Mars had a thicker atmosphere in the past.
What a bunch of contrasts in the inner Solar System: practically atmosphere-less Mercury, a runaway hothouse greenhouse effect happening in Venus’ thick atmosphere, temperate conditions on much of Earth and then a thin atmosphere on Mars. But look at the planet and you can see gullies carved in the past from probable water. Water requires more atmosphere, so Mars had more in the past. Where did it go? Some scientists believe it’s because the Sun’s energy pushed the lighter molecules out of Mars’ atmosphere over millions of years, decreasing the thickness over time.
4. Jupiter is a great comet catcher.
The most massive planet in the Solar System probably had a huge influence on its history. At 318 times the mass of Earth, you can imagine that any passing asteroid or comet going near Jupiter has a big chance of being caught or diverted. Maybe Jupiter was partly to blame for the great bombardment of small bodies that peppered our young Solar System early in its history, causing scars you can still see on the Moon today. And in 1994, astronomers worldwide were treated to a rare sight: a comet, Shoemaker-Levy 9, breaking up under Jupiter’s gravity and slamming into the atmosphere.
Fragmentation of comets is common. Many sungrazers are broken up by thermal and tidal stresses during their perihelions. At top, an image of the comet Shoemaker-Levy 9 (May 1994) after a close approach with Jupiter which tore the comet into numerous fragments. An image taken by Andrew Catsaitis of components B and C of Comet 73P/Schwassmann–Wachmann 3 as seen together on 31 May 2006 (Credit: NASA/HST, Wikipedia, A.Catsaitis)
5. No one knows how old Saturn’s rings are
There’s a field of ice and rock debris circling Saturn that from afar, appear as rings. Early telescope observations of the planet in the 1600s caused some confusion: does that planet have ears, or moons, or what? With better resolution, however, it soon became clear that there was a chain of small bodies encircling the gas giant. It’s possible that a single moon tore apart under Saturn’s strong gravity and produced the rings. Or, maybe they’ve been around (pun intended) for the last few billion years, unable to coalesce into a larger body but resistant enough to gravity not to break up.
6. Uranus is more stormy than we thought.
When Voyager 2 flew by the planet in the 1980s, scientists saw a mostly featureless blue ball and some assumed there wasn’t much activity going on on Uranus. We’ve had a better look at the data since then that does show some interesting movement in the southern hemisphere. Additionally, the planet drew closer to the Sun in 2007, and in more recent years telescope probing has shown some storms going on. What is causing all this activity is difficult to say unless we were to send another probe that way. And unfortunately, there are no missions yet that are slated for sure to zoom out to that part of the Solar System.
Infrared images of Uranus showing storms at 1.6 and 2.2 microns obtained Aug. 6, 2014 by the 10-meter Keck telescope. Credit: Imke de Pater (UC Berkeley) & Keck Observatory images.
7. Neptune has supersonic winds.
While on Earth we are concerned about hurricanes, the strength of these storms is nowhere near what you would find on Neptune. At its highest altitudes, according to NASA, winds blow at more than 1,100 miles per hour (1,770 kilometers per hour). To put that in context, that’s faster than the speed of sound on Earth, at sea level. Why Neptune is so blustery is a mystery, especially considering the Sun’s heat is so little at its distance.
8. You can see Earth’s magnetic field at work during light shows.
We have a magnetic field surrounding our planet that protects us from the blasts of radiation and particles the Sun sends our way. Good thing, too, because such flare-ups could prove deadly to unprotected people; that’s why NASA keeps an eye on solar activity for astronauts on the International Space Station, for example. At any rate, when you see auroras shining in the sky, that’s what happens when the particles from the Sun flow along the magnetic field lines and interact with Earth’s upper atmosphere.
Universe Today has many articles on interesting facts about the planets. Start with 10 facts about Mercury and 10 facts about Venus. You may also want to check out the 10 facts about Mars. Astronomy Cast also has a number of podcasts about the planets, including one on Earth.
Betelgeuse was the first star directly imaged -- besides our own Sun, of course. Image obtained by the Hubble Space Telescope. Credit: Andrea Dupree (Harvard-Smithsonian CfA), Ronald Gilliland (STScI), NASA and ESA
While there are untold billions of celestial objects visible in the nighttime sky, some of them are better known than others. Most of these are stars that are visible to the naked eye and very bright compared to other stellar objects. For this reason, most of them have a long history of being observed and studied by human beings, and most likely occupy an important place in ancient folklore.
So without further ado, here is a sampling of some of the better-known stars in that are visible in the nighttime sky:
Polaris: Also known as the North Star (as well as the Pole Star, Lodestar, and sometimes Guiding Star), Polaris is the 45th brightest star in the night sky. It is very close to the north celestial pole, which is why it has been used as a navigational tool in the northern hemisphere for centuries. Scientifically speaking, this star is known as Alpha Ursae Minoris because it is the alpha star in the constellation Ursa Minor (the Little Bear).
The Polaris star system, as seen within the Ursa Minor constellation and up close. Credit: NASA, ESA, N. Evans (Harvard-Smithsonian CfA), and H. Bond (STScI)
It’s more than 430 light-years away from Earth, but its luminosity (being a white supergiant) makes it highly visible to us here on Earth. What’s more, rather than being a single supergiant, Polaris is actually a trinary star system, comprised of a main star (alpha UMi Aa) and two smaller companions (alpha UMi B, alpha UMi Ab). These, along with its two distant components (alpha UMi C, alpha UMi D), make it a multistar system.
Interestingly enough, Polaris wasn’t always the north star. That’s because Earth’s axis wobbles over thousands of years and points in different directions. But until such time as Earth’s axis moves farther away from the “Polestar”, it remains our guide.
Because it is what is known as a Cepheid variable star – i.e. a star that pulsates radially, varying in both temperature and diameter to produce brightness changes – it’s distance to our Sun has been the subject of revision. Many scientific papers suggest that it may be up to 30% closer to our Solar System than previously expected – putting it in the vicinity of 238 light years away.
Time exposure centered on Polaris, the North Star. Notice that the closer stars are to Polaris, the smaller the circles they describe. Stars at the edge of the frame make much larger circles. Credit: Bob King
Sirius: Also known as the Dog Star, because it’s the brightest star in Canis Major (the “Big Dog”), Sirius is also the brightest star in the night sky. The name “Sirius” is derived from the Ancient Greek “Seirios“, which translates to “glowing” or “scorcher”. Whereas it appears to be a single bright star to the naked eye, Sirius is actually a binary star system, consisting of a white main-sequence star named Sirius A, and a faint white dwarf companion named Sirius B.
The reason why it is so bright in the sky is due to a combination of its luminosity and distance – at 6.8 light years, it is one of Earth’s nearest neighbors. And in truth, it is actually getting closer. For the next 60,000 years or so, astronomers expect that it will continue to approach our Solar System; at which point, it will begin to recede again.
In ancient Egypt, it was seen as a signal that the flooding of the Nile was close at hand. For the Greeks, the rising of Sirius in the night sky was a sign of the”dog days of summer”. To the Polynesians in the southern hemisphere, it marked the approach of winter and was an important star for navigation around the Pacific Ocean.
Alpha Centauri System: Also known as Rigel Kent or Toliman, Alpha Centauri is the brightest star in the southern constellation of Centaurus and the third brightest star in the night sky. It is also the closest star system to Earth, at just a shade over four light-years. But much like Sirius and Polaris, it is actually a multistar system, consisting of Alpha Centauri A, B, and Proxima Centauri (aka. Centauri C).
Artist’s impression of the planet around Alpha Centauri B. Credit: ESO
Based on their spectral classifications, Alpha Centauri A is a main sequence white dwarf with roughly 110% of the mass and 151.9% the luminosity of our Sun. Alpha Centauri B is an orange subgiant with 90.7% of the Sun’s mass and 44.5% of its luminosity. Proxima Centauri, the smallest of the three, is a red dwarf roughly 0.12 times the mass of our Sun, and which is the closest of the three to our Solar System.
English explorer Robert Hues was the first European to make a recorded mention of Alpha Centauri, which he did in his 1592 work Tractatus de Globis. In 1689, Jesuit priest and astronomer Jean Richaud confirmed the existence of a second star in the system. Proxima Centauri was discovered in 1915 by Scottish astronomer Robert Innes, Director of the Union Observatory in Johannesburg, South Africa.
Betelgeuse: Pronounced “Beetle-juice” (yes, the same as the 1988 Tim Burton movie), this bright red supergiant is roughly 65o light-year from Earth. Also known as Alpha Orionis, it is nevertheless easy to spot in the Orion constellation since it is one of the largest and most luminous stars in the night sky.
Betelgeuse, as seen by the Hubble Space Telescope, and in relation to the Orion constellation. Credit: NASA
The star’s name is derived from the Arabic name Ibt al-Jauza’, which literally means “the hand of Orion”. In 1985, Margarita Karovska and colleagues from the Harvard–Smithsonian Center for Astrophysics, announced the discovery of two close companions orbiting Betelgeuse. While this remains unconfirmed, the existence of possible companions remains an intriguing possibility.
What excites astronomers about Betelgeuse is it will one day go supernova, which is sure to be a spectacular event that people on Earth will be able to see. However, the exact date of when that might happen remains unknown.
Rigel: Also known as Beta Orionis, and located between 700 and 900 light years away, Rigel is the brightest star in the constellation Orion and the seventh brightest star in the night sky. Here too, what appears to be a blue supergiant is actually a multistar system. The primary star (Rigel A) is a blue-white supergiant that is 21 times more massive than our sun, and shines with approximately 120,000 times the luminosity.
Rigel B is itself a binary system, consisting of two main sequence blue-white subdwarf stars. Rigel B is the more massive of the pair, weighing in at 2.5 Solar masses versus Rigel C’s 1.9. Rigel has been recognized as being a binary since at least 1831 when German astronomer F.G.W. Struve first measured it. A fourth star in the system has been proposed, but it is generally considered that this is a misinterpretation of the main star’s variability.
Rigel A is a young star, being only 10 million years old. And given its size, it is expected to go supernova when it reaches the end of its life.
Vega: Vega is another bright blue star that anchors the otherwise faint Lyra constellation (the Harp). Along with Deneb (from Cygnus) and Altair (from Aquila), it is a part of the Summer Triangle in the Northern hemisphere. It is also the brightest star in the constellation Lyra, the fifth brightest star in the night sky and the second brightest star in the northern celestial hemisphere (after Arcturus).
Characterized as a white dwarf star, Vega is roughly 2.1 times as massive as our Sun. Together with Arcturus and Sirius, it is one of the most luminous stars in the Sun’s neighborhood. It is a relatively close star at only 25 light-years from Earth.
Vega was the first star other than the Sun to be photographed and the first to have its spectrum recorded. It was also one of the first stars whose distance was estimated through parallax measurements, and has served as the baseline for calibrating the photometric brightness scale. Vega’s extensive history of study has led it to be termed “arguably the next most important star in the sky after the Sun.”
Artist’s concept of a recent massive collision of dwarf planet-sized objects that may have contributed to the dust ring around the star Vega. Credit: NASA/JPL/Caltech/T. Pyle (SSC)
Based on observations that showed excess emission of infrared radiation, Vega is believed to have a circumstellar disk of dust. This dust is likely to be the result of collisions between objects in an orbiting debris disk. For this reason, stars that display an infrared excess because of circumstellar dust are termed “Vega-like stars”.
Thousands of years ago, (ca. 12,000 BCE) Vega was used as the North Star is today, and will be so again around the year 13,727 CE.
Pleiades: Also known as the “Seven Sisters”, Messier 45 or M45, Pleiades is actually an open star cluster located in the constellation of Taurus. At an average distance of 444 light years from our Sun, it is one of the nearest star clusters to Earth, and the most visible to the naked eye. Though the seven largest stars are the most apparent, the cluster actually consists of over 1,000 confirmed members (along with several unconfirmed binaries).
The core radius of the cluster is about 8 light years across, while it measures some 43 light years at the outer edges. It is dominated by young, hot blue stars, though brown dwarfs – which are just a fraction of the Sun’s mass – are believed to account for 25% of its member stars.
Pleiades, also known as M45, is a prominent open star cluster in the sky. Image Credit: Jamie Ball
The age of the cluster has been estimated at between 75 and 150 million years, and it is slowly moving in the direction of the “feet” of what is currently the constellation of Orion. The cluster has had several meanings for many different cultures here on Earth, which include representations in Biblical, ancient Greek, Asian, and traditional Native American folklore.
Antares: Also known as Alpha Scorpii, Antares is a red supergiant and one of the largest and most luminous observable stars in the nighttime sky. It’s name – which is Greek for “rival to Mars” (aka. Ares) – refers to its reddish appearance, which resembles Mars in some respects. It’s location is also close to the ecliptic, the imaginary band in the sky where the planets, Moon and Sun move.
This supergiant is estimated to be 17 times more massive, 850 times larger in terms of diameter, and 10,000 times more luminous than our Sun. Hence why it can be seen with the naked eye, despite being approximately 550 light-years from Earth. The most recent estimates place its age at 12 million years.
A red supergiant, Antares is over 850 times the diameter of our own Sun, 15 times more massive, and 10,000 times brighter. Credit: NASA/Ivan Eder
Antares is the seventeenth brightest star that can be seen with the naked eye and the brightest star in the constellation Scorpius. Along with Aldebaran, Regulus, and Fomalhaut, Antares comprises the group known as the ‘Royal stars of Persia’ – four stars that the ancient Persians (circa. 3000 BCE) believed guarded the four districts of the heavens.
Canopus: Also known as Alpha Carinae, this white giant is the brightest star in the southern constellation of Carina and the second brightest star in the nighttime sky. Located over 300 light-years away from Earth, this star is named after the mythological Canopus, the navigator for king Menelaus of Sparta in The Iliad.
Thought it was not visible to the ancient Greeks and Romans, the star was known to the ancient Egyptians, as well as the Navajo, Chinese and ancient Indo-Aryan people. In Vedic literature, Canopus is associated with Agastya, a revered sage who is believed to have lived during the 6th or 7th century BCE. To the Chinese, Canopus was known as the “Star of the Old Man”, and was charted by astronomer Yi Xing in 724 CE.
Image of Canopus, as taken by crew members aboard the ISS. Credit: NASA
It is also referred to by its Arabic name Suhayl (Soheil in persian), which was given to it by Islamic scholars in the 7th Century CE. To the Bedouin people of the Negev and Sinai, it was also known as Suhayl, and used along with Polaris as the two principal stars for navigation at night.
It was not until 1592 that it was brought to the attention of European observers, once again by Robert Hues who recorded his observations of it alongside Achernar and Alpha Centauri in his Tractatus de Globis (1592).
As he noted of these three stars, “Now, therefore, there are but three Stars of the first magnitude that I could perceive in all those parts which are never seene here in England. The first of these is that bright Star in the sterne of Argo which they call Canobus. The second is in the end of Eridanus. The third is in the right foote of the Centaure.”
