Asteroids Archives

January 26, 2015December 23, 2015 by Morgan Rehnberg

Are Asteroids the Future of Planetary Science?

The asteroid Vesta as seen by the Dawn spacecraft. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA

I don’t think I ever learned one of those little rhymes – My Very Educated Mother Just Served Us Nine Pizzas – to memorize the order of the planets, but if I had, it would’ve painted for me a minimalist picture of the solar system. (Side question: what is my Very Educated Mother serving now that we only have Dwarf Pizzas?) After all, much of the most exciting work in planetary science today happens not at the planets, but around them.

Ask an astronomer where in the solar system she’d like to visit next and you’re just as likely to hear Europa, Enceladus, Titan, or Triton as you are Venus, Mars, or Neptune. Our solar system hosts eight planets but nearly 200 known moons. And moons, it turns out, are just the start. We’ve detected more than a million asteroids; surely that’s just a fraction of what’s lurking beyond our limits of observation. Let’s not even think about the billions, perhaps even trillions, of Kuiper belt and Oort cloud objects – we could be here all day! So, while the planets may dominate the solar system gravitationally, they are pitiful numerically.

If there is one thing that the study of exoplanets has taught us in the last twenty years, it’s that the Universe thrives on chance. Given enough planets (and there appear to be gazillions out there!), practically anything can happen. Want a planet with a double sunset? We’ve got that, but perhaps you’d prefer one with three! How about a planet whose temperature is nearly half that of the surface of the Sun? No problem there. I can even offer you a planet ten times more massive than Jupiter, but nearly 20 times closer to its star than Mercury (probably not the best place for your first off-world vacation home…). The point is, with only a few thousand planets discovered, what we’ve seen already is astonishing. Imagine what those million asteroids could be hiding.

In fact, asteroids might be the next great frontier in planetary science. Let’s find out why.

An artist's impression of the rings around Chariklo. Credit: ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org) — An artist’s impression of the rings around Chariklo. Credit:
ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org)

Suppose I ask you to think about the planet Saturn. What’s the first thing that jumps to mind? Probably its rings. And, if you were paying attention around the time you learned one of those nifty rhymes, you might recall that Jupiter, Uranus, and Neptune also have rings. But, did you know that at least one asteroid is also home to a ring system? Called Chariklo, it’s the largest known of a family of asteroids trapped between the orbits of the outer planets. Early last year, astronomers reported the detection of a ring system about this 250-kilometer sized object. I say a ring system because there appear to be at least two distinct rings encircling Chariklo. Discovering this new system is more than just an additional data point. Perhaps the paramount question facing the field of planetary rings today is how they formed and how long they can last; the existence of rings around a tiny asteroid tells a very different story than that implied by the giant planets.

Of course, rings haven’t been the biggest planetary science story of the last decade (much to my chagrin as a rings researcher!). That honor might instead lie with geysers. The 2005 discovery of an enormous water plume emanating from the surface of Saturn’s moon Enceladus changed the way we looked at the icy moons of the solar system. Eight years later, astronomers using Hubble claimed to have found a similar phenomenon at Jupiter’s moon Europa (now they’re not so sure). But geysers, too, might not be the sole province of planetary moons. Just last year, researchers with the Herschel Space Telescope found the first evidence for water vapor emanating from the surface of the enormous asteroid Ceres! There’s more good news: unlike Europa, with its off-in-the-future mission, the Dawn spacecraft is on its way to Ceres right now. It will arrive in just under two months and provide a close-up look at the second confirmed off-world geyser.

Speaking of moons, it probably won’t surprise you to learn that asteroids have those, too! In fact, the number of asteroids with known satellites is far too long to enumerate here. But, they are not merely numerous; the variety of asteroid moons seems to be nearly as large as the variety of asteroids themselves. Like with the planets, many asteroids dwarf their moons. Others, though, are more like binary systems in which both bodies are approximately the same size. And, although we generally know little about their shape, the variety in this realm also appears tremendous.

An artist's conception of how an unmanned spacecraft might redirect an asteroid into lunar orbit. Credit: NASA — An artist’s conception of how an unmanned spacecraft might redirect an asteroid into lunar orbit. Credit: NASA

Ultimately, though, it’s not their number or their variety that might make asteroids the future of planetary science; the laws of physics are on their side. It’s no accident that NASA intends to send astronauts to land on an asteroid long before they attempt to touch down on Mars. Neither is it a coincidence that at least three missions (Hayabusa, Hayabusa 2, and OSIRIS-REx) will have returned, or at least attempted to, samples from an asteroid to the Earth before NASA’s ambitious plan to do the same at Mars. The gravitational tug on the surface of the Red Planet is more than thirteen times more powerful than that of even the largest asteroid.

We’re seeing this accessibility in action already. Hayabusa returned a sample of asteroid Itokawa back in 2010 and its successor is already on its way. And, remember Dawn on its way to Ceres? It turns out that wasn’t its first stop. Before setting out for the solar system’s largest asteroid, the mission spent fourteen months in orbit about the asteroid Vesta. When it arrives at Ceres in March, Dawn will become the first spacecraft in history to orbit two extraterrestrial bodies.

Dawn is, I think, a signal of things to come. Asteroids, in general, and the main asteroid belt, in particular, offer the tantalizing opportunity to visit a variety of different worlds in one fell swoop. These are places that are closer to us, easier to approach, and just as scientifically interesting as the classical celestial worlds. Does this mean that the world’s science agencies will or even should abandon the study of the planets? Of course not. No asteroid looks like the cloud tops of Jupiter or the methane lakes of Titan or the intense heat of Venus. I’m not at all trying to limit the worlds which we visit. Quite the opposite, in fact: we’ve suddenly found a million new places to go!

January 26, 2015December 23, 2015 by Bob King

News Flash: Asteroid Flying Past Earth Today Has Mini-Moon!

This animation, created from individual radar images, clearly show the rough outline of 2004 BL86 and its newly-discovered moon. Credit: NASA/JPL-Caltech

Wonderful news! Asteroid 2004 BL86, which passed closest to Earth today at a distance of 750,000 miles (1.2 million km), has a companion moon. Scientists working with NASA’s 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, California, have released the first radar images of the asteroid which show the tiny object in orbit about the main body.

While these are the first images of it, the “signature” of the satellite was seen in light curve data reported earlier by Joseph Pollock (Appalachian State University, North Carolina) and Petr Prave (Ondrejov Observatory, Czech Republic) according to Lance Benner who works with the radar team at Goldstone.

2004 BL86 measures about 1,100 feet (325 meters) across while its moon is approximately 230 feet (70 meters) across. The asteroid made its closest approach today (Jan. 26th) at 10:19 a.m. (CST), however it will peak in brightness this evening around 10 p.m. (4:00 UT) at magnitude +9.0. Unlike some flybys, 2004 BL86 will remain within a few tenths of a magnitude of peak brightness from 6 p.m. tonight (CST) through early tomorrow morning, so don’t miss the chance to see it in your telescope.

Don’t expect to see the diminutive moon visually – the entire system will only appear as a point of light, but I’m sure you’ll agree it’s cool just knowing it’s there.

The double asteroid (90) Antiope and S/2000 (90) 1. The two objects are separated by 171 km, and they perform their celestial dance in 16.5 hours. The adaptive optics observations could, however, never resolve the shape of the individual components as they are too small. Credit: ESO — The double asteroid (90) Antiope and its companion S/2000 (90) 1. The two objects are separated by 106 miles (171 km), and they perform their celestial dance in 16.5 hours. The adaptive optics observations couldn’t resolve the shape of the individual components as they are too small. Credit: ESO

Among near-Earth asteroids, about 16% that are about 655 feet (200 meters) or larger are either binary or triple systems. While that’s not what you’d call common, it’s not unusual either. To date, we know of 240 asteroids with a single moon, 10 triple systems and the sextuple system of Pluto (I realize that’s stretching a bit, since Pluto’s a dwarf planet) – 268 companions total. 52 of those are near-Earth asteroids.

With a resolution of 13 feet (4-meters) per pixel we can at least see the roughness of the the main body’s surface and perhaps imagine craters there. No details are visible on the moon though it does appear elongated. I’m surprised how round the main body is given its small size. An object that tiny doesn’t normally have the gravity required to crush itself into a sphere. Yet another fascinating detail needing our attention.

Of course the main asteroid will get your attention tonight. Please check out our earlier story on 2004 BL86 which includes more details as well as charts to help you track it as it flies across Cancer the Crab tonight. This is the best view we’re going to get of it for the next two centuries.

January 19, 2015December 23, 2015 by Nancy Atkinson

Here’s Ceres Compared to All the Other Asteroids We’ve Visited

Ceres compared to asteroids visited to date, including Vesta, Dawn's mapping target in 2011. Image by NASA/ESA. Compiled by Paul Schenck.

When the Dawn mission was in its planning stages, Ceres was considered an asteroid. But in 2006, a year before the mission launched, the International Astronomical Union formed a new class of solar system objects known as dwarf planets, and since by definition a dwarf planet is spherical and travels in an orbit around the Sun, Ceres fit that definition perfectly.

But since it’s located in the Asteroid Belt, we still tend to think of Ceres as an asteroid. So, how does Ceres compare to other asteroids?

Dr. Paul Schenk, who is a participating scientist on the Dawn mission, recently put together some graphics on his website and the one above compares Ceres to other asteroids that we’ve visited with spacecraft.

Of course, Ceres is bigger (it’s the biggest object in the Asteroid Belt) and more spherical than the other asteroids. When it comes right down to it, Ceres doesn’t look much like an asteroid at all!

“Ceres is most similar in size to several of Saturn’s icy moons and may be similar internally as well, being composed of 25% water ice by mass,” Schenk noted on his website.

Comparisons of Ceres with other prominent icy objects. Dione is Ceres' closest twin in size and mass. Image credit: NASA/ESA. Compiled by Paul Schenk. — Comparisons of Ceres with other prominent icy objects. Dione is Ceres’ closest twin in size and mass. Image credit: NASA/ESA. Compiled by Paul Schenk.

And water is one of the most interesting and mysterious aspects of Ceres. A year ago, the Herschel space telescope discovered water vapor around Ceres, and the vapor could be emanating from water plumes — much like those that are on Saturn’s moon Enceladus – or it could be from cryovolcanism from geysers or icy volcano.

“The water vapor question is one of the most interesting things we will look for,” Schenk told Universe Today. “What is its source, what does it indicate about the interior and activity level within Ceres? Is Ceres active, very ancient, or both? Does it go back to the earliest Solar System? Those are the questions we hope to answer with Dawn.”

Some scientists also think Ceres may have an ocean and possibly an atmosphere, which makes Dawn’s arrival at Ceres in March one of the most exciting planetary events of 2015, in addition to New Horizon’s arrival at Pluto.

“Since we don’t know why the water vapor venting has happened, or even if it continues, it’s hard to say much more than that,” Schenk said via email, “but it is theoretically possible that some liquid water still exists within Ceres. Dawn will try to determine if that is true.”

One of the possibilities that has been discussed is that if the water vapor is confirmed, Ceres could potentially host microbial life. I asked Schenk what other factors would have to be present in order for that to have occurred?

“The presence of carbon molecules is often regarded as necessary for life,” he replied, “and we think we see that on the surface spectroscopically in the form of carbonates and clays. So, I think the questions will be, whether there is actually liquid water of any kind, whether the carbon compounds are just a surface coating or in the interior, and whether Ceres has ever been warm. If those are true then some sort of prebiotic or biotic activity is in play.”

Since we do not know the answer to any of these questions yet, Schenk says Dawn’s visit to Ceres should be interesting!

On thing of note is that Dawn is now closing in on Ceres and just today, the team released the best image we have yet of Ceres, which you can see in our article here.

Read more of Schenk’s article, “Year of the ‘Dwarves’: Ceres and Pluto Get Their Due.”

Keep tabs on the Dawn mission by following Universe Today, or see the Dawn mission website.

January 19, 2015December 23, 2015 by Jason Major

Here’s Dawn’s Best View of Ceres Yet

Animation of Ceres made from Dawn images acquired on Jan. 13, 2015 (Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI)

Just sit back and watch the world turn… or should I say, watch the dwarf planet turn in this fascinating animation from Dawn as the spacecraft continues on its ion-powered approach to Ceres!

The images were captured by Dawn’s framing camera over the course on an hour on Jan. 13 at a distance of 238,000 miles (383,000 km) from Ceres. At 590 miles (950 km) wide Ceres is the largest object in the main asteroid belt.

“Already, the [latest] images hint at first surface structures such as craters,” said Andreas Nathues, lead investigator for the framing camera team at the Max Planck Institute for Solar System Research in Gottingen, Germany. “We have identified all of the features seen by Hubble on the side of Ceres we have observed, and there are also suggestions of remarkable structures awaiting us as we move even closer.”

Although these latest 27-pixel images from Dawn aren’t quite yet better than Hubble’s images from Jan. 2004, very soon they will be.

Comparison of HST and Dawn FC images of Ceres taken nearly 11 years apart

“The team is very excited to examine the surface of Ceres in never-before-seen detail,” said Chris Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles. “We look forward to the surprises this mysterious world may bring.”

Launched Sept. 27, 2007, Dawn previously spent over 13 months in orbit around the asteroid/protoplanet Vesta from 2011–12 and is now on final approach to Ceres. On March 6 Dawn will arrive at Ceres, becoming the first spacecraft to enter orbit around two different target worlds.

Learn more at JPL’s Dawn mission site here, and find out where Dawn is right now here.

Also, read more from the Max Planck Institute for Solar System Research here.

Source: NASA/MPI

January 15, 2015April 26, 2016 by Bob King

Big Asteroid 2004 BL86 Buzzes Earth on January 26: How to See it in Your Telescope

Artist view of an asteroid passing Earth. Credit: ESA/P.Carril

A lot of asteroids pass near Earth every year. Many are the size of a house, make close flybys and zoom out of the headlines. 2004 BL86 is a bit different. On Monday evening January 26th, it will become the largest asteroid to pass closest to Earth until 2027 when 1999 AN10 will approach within one lunar distance.

Big is good. 2004 BL86 checks in at 2,230 feet (680-m) wide or nearly half a mile. Add up its significant size and relatively close approach – 745,000 miles (1.2 million km) – and something wonderful happens. This newsy space rock is expected to reach magnitude +9.0, bright enough to see in a 3-inch telescope or even large binoculars.

This graphic depicts the passage of asteroid 2004 BL86, which will come no closer than about three times the distance from Earth to the moon on Jan. 26, 2015. Due to its orbit around the sun, the asteroid is currently only visible by astronomers with large telescopes who are located in the southern hemisphere. But by Jan. 26, the space rock's changing position will make it visible to those in the northern hemisphere. Click to see an animation. Credit: NASA/JPL-Caltech — This graphic depicts the passage of asteroid 2004 BL86, which will safely pass by the Earth on January 26th. Closest approach occurs around 10 a.m (CST) that day. The asteroid is currently only visible by astronomers with large telescopes who are located in the southern hemisphere. But by Jan. 26, the space rock’s changing position will make it visible to those in the northern hemisphere. Click to see an animation. Credit: NASA/JPL-Caltech

This is a rare opportunity then to see an Earth-approaching asteroid so easily. All you need is a good map as 2004 BL86 will be zipping along at two arc seconds per second or two degrees (four Moon diameters) per hour. That means you’ll see it move in real time like a slow satellite inching its way across the sky. Cool!

As you can see from its name, 2004 BL86 was discovered 11 years ago in 2004 by the Lincoln Near-Earth Asteroid Research (LINEAR), an MIT Lincoln Laboratory program to track near-Earth objects funded by the U.S. Air Force and NASA. As of September 15, 2011, the search has swept up 2,423 new asteroids and 279 new comets.

Map showing the hourly progress of 2004 BL86 Monday evening January 26th as it treks across Cancer the Crab not far from Jupiter. Stars are shown to magnitude +9. The number at the tick marks show the time (CST) each hour starting at 6 p.m., then 7 p.m., 8 p.m. and so on. Click for a larger version. Created with Chris Marriott's SkyMap program — Map showing the hourly progress of 2004 BL86 Monday evening January 26th as it treks across Cancer the Crab not far from Jupiter. Stars are shown to magnitude +9. Numbers at the tick marks show the time (CST) each hour starting at 6 p.m., then 7 p.m., 8 p.m. and so on. Click for a larger version. Created with Chris Marriott’s SkyMap program

All asteroids with well-known orbits receive a number. The first asteroid, 1 Ceres, was discovered in 1801. The 4,150th asteroid, 4150 Starr and named for the Beatles’ Ringo Starr, was found in 1984. 2004 BL86 will likely be the highest-numbered asteroid any of us will ever see. How does 357,439 sound to you?

Some observers prefer a black on white map for tracking asteroids and deep sky objects. Click to view a larger version. Created with Chris Marriott's SkyMap program — Some observers prefer a black on white map for tracking asteroids and deep sky objects. Click to view a larger version. Created with Chris Marriott’s SkyMap program

Observers in the Americas, Europe and Africa will have the best seats for viewing the asteroid, which will shine brightest between 7 p.m. and midnight CST from a comfortably high perch in Cancer the Crab not far from Jupiter. The half-moon will also be out but over in the western sky, so shouldn’t get in the way of seeing our speedy celeb.

Not only will 2004 BL86 pass near a few fairly bright stars but the Beehive Cluster (M44) will temporarily gain a new member between 11 p.m. and midnight as the asteroid buzzes across the well-known star cluster.

“Monday, January 26 will be the closest asteroid 2004 BL86 will get to Earth for at least the next 200 years,” said Don Yeomans, who’s retiring as manager of NASA’s Near Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California, after 16 years in the position.

More detailed map showing the hourly position of the asteroid through central Cancer. Stars plotted to magnitude +9.5. Created with Chris Marriott's SkyMap software — More detailed map showing the hourly position of the asteroid through central Cancer. Stars plotted to magnitude +9.5. Click to get a larger version. Created with Chris Marriott’s SkyMap software

To learn more about the space rock and acquire close-ups of its surface, NASA’s Deep Space Network antenna at Goldstone, California, and the Arecibo Observatory in Puerto Rico will attempt to ping the asteroid with microwaves to create radar-generated images of the asteroid during the days surrounding its closest approach to Earth.

“When we get our radar data back the day after the flyby, we will have the first detailed images,” said radar astronomer Lance Benner of JPL, principal investigator for the Goldstone radar observations of the asteroid. “At present, we know almost nothing about the asteroid, so there are bound to be surprises.”

NASA's Deep Space Network will be watching during 2004 BL86's flyby Monday Jan. 26. Credit: NASA — NASA’s Deep Space Network will be watching during 2004 BL86’s flyby Monday Jan. 26. Credit: NASA

While 2004 BL86 will be brightest Monday night, that’s not the only time amateur astronomers might see it. It comes into view for southern hemisphere observers around magnitude +13 on Jan. 24 and leaves the scene at a similar brightness high in the northeastern sky in the northern hemisphere on the 29th. If you use a star-charting program like Starry Night, Guide, MegaStar and others, you can get updated orbital element packages HERE. Just select your program and download the Observable Unusual Minor Planets file. Open it in your software and create maps for the entire apparition.

One last observing tip before you go your own way. Close asteroids will sometimes be a little bit off a particular track depending on your location. Not much but enough that I recommend you scan not just the single spot where you expect to see it but also nearby in the field of view. If you see a “star” on the move – that’s it.

As always, Dr. Gianluca Masi, Italian astrophysicist, will share his live coverage of the event beginning at 1:30 p.m. (19:30 UT) Jan. 26th.

Let us know if you see our not-so-little cosmic friend. Good luck!

January 13, 2015December 23, 2015 by Matt Williams

Faster-Than-Light Lasers Could “Illuminate” the Universe

The Very Large Telescoping Interferometer firing it's adaptive optics laser. Credit: ESO/G. Hüdepohl

It’s a cornerstone of modern physics that nothing in the Universe is faster than the speed of light (c). However, Einstein’s theory of special relativity does allow for instances where certain influences appear to travel faster than light without violating causality. These are what is known as “photonic booms,” a concept similar to a sonic boom, where spots of light are made to move faster than c.

And according to a new study by Robert Nemiroff, a physics professor at Michigan Technological University (and co-creator of Astronomy Picture of the Day), this phenomena may help shine a light (no pun!) on the cosmos, helping us to map it with greater efficiency.

Consider the following scenario: if a laser is swept across a distant object – in this case, the Moon – the spot of laser light will move across the object at a speed greater than c. Basically, the collection of photons are accelerated past the speed of light as the spot traverses both the surface and depth of the object.

The resulting “photonic boom” occurs in the form of a flash, which is seen by the observer when the speed of the light drops from superluminal to below the speed of light. It is made possible by the fact that the spots contain no mass, thereby not violating the fundamental laws of Special Relativity.

An image of NGC 2261 (aka. Hubble's Variable Nebula) by the Hubble space telescope. Credit: HST/NASA/JPL. — *An image of NGC 2261 (aka. Hubble’s Variable Nebula) by the Hubble space telescope. Image Credit: HST/NASA/JPL.*

Another example occurs regularly in nature, where beams of light from a pulsar sweep across clouds of space-borne dust, creating a spherical shell of light and radiation that expands faster than c when it intersects a surface. Much the same is true of fast-moving shadows, where the speed can be much faster and not restricted to the speed of light if the surface is angular.

At a meeting of the American Astronomical Society in Seattle, Washington earlier this month, Nemiroff shared how these effects could be used to study the universe.

“Photonic booms happen around us quite frequently,” said Nemiroff in a press release, “but they are always too brief to notice. Out in the cosmos they last long enough to notice — but nobody has thought to look for them!”

Superluminal sweeps, he claims, could be used to reveal information on the 3-dimensional geometry and distance of stellar bodies like nearby planets, passing asteroids, and distant objects illuminated by pulsars. The key is finding ways to generate them or observe them accurately.

For the purposes of his study, Nemiroff considered two example scenarios. The first involved a beam being swept across a scattering spherical object – i.e. spots of light moving across the Moon and pulsar companions. In the second, the beam is swept across a “scattering planar wall or linear filament” – in this case, Hubble’s Variable Nebula.

Artist view of an asteroid (with companion) passing near Earth. Credit: P. Carril / ESA — *Photonic booms caused by laser sweeps could offer a new imaging technique for mapping out passing asteroids. Credit: P. Carril / ESA*

In the former case, asteroids could be mapped out in detail using a laser beam and a telescope equipped with a high-speed camera. The laser could be swept across the surface thousands of times a second and the flashes recorded. In the latter, shadows are observed passing between the bright star R Monocerotis and reflecting dust, at speeds so great that they create photonic booms that are visible for days or weeks.

This sort of imaging technique is fundamentally different from direct observations (which relies on lens photography), radar, and conventional lidar. It is also distinct from Cherenkov radiation – electromagnetic radiation emitted when charged particles pass through a medium at a speed greater than the speed of light in that medium. A case in point is the blue glow emitted by an underwater nuclear reactor.

Combined with the other approaches, it could allow scientists to gain a more complete picture of objects in our Solar System, and even distant cosmological bodies.

Nemiroff’s study accepted for publication by the Publications of the Astronomical Society of Australia, with a preliminary version available online at arXiv Astrophysics

Further reading:
Michigan Tech press release
Robert Nemiroff/Michigan Tech

December 31, 2014December 23, 2015 by Elizabeth Howell

Asteroids Don’t Break Up Like You Think They Do: Study

Artist's impression of an asteroid breaking up. Credit: NASA/JPL-Caltech

The early Solar System was a shooting gallery. Smaller-body collisions happened far more frequently than we see it today, pockmarking the Moon and Mercury. On a larger scale, simulation show the Earth came close to blowing apart when a Mars-sized object crashed into us long ago.

So we’d be forgiven for thinking that it’s asteroid collisions that cause these tiny bodies to break up, given their numbers and the history of our neighborhood. But it turns out, a new study says, that the larger asteroids likely have another way of coming apart.

“For asteroids about 100 meters [328 feet] in diameter collisions are not the primarily cause of break ups – rapid rotation is,” the Smithsonian Astrophysical Observatory stated.

“Moreover, because the rate of collisions depends on the numbers and sizes of objects but rotation does not, their results are in strong disagreement with previous models of collisionally-produced small asteroids.”

Most near-Earth asteroids fall into three classes named after the first asteroid discovered in that class. Apollo and Aten asteroids cross Earth's orbit; Amors orbit just beyond Earth but cross Mars' orbit. Credit: Wikipedia — Most near-Earth asteroids fall into three classes named after the first asteroid discovered in that class. Apollo and Aten asteroids cross Earth’s orbit; Amors orbit just beyond Earth but cross Mars’ orbit. Credit: Wikipedia

It turns out that rotation has a strong effect on such a small body. First, the asteroid is emitting stuff that can produce a spin — water evaporating, or its surface expanding as heat from the Sun strikes it. Also, the Sun’s pressure on the asteroid creates a rotation. Between these different effects, at the right (or wrong) moment it can cause a catastrophic breakup.

As a simulation (coupled with observations from the Pan-STARRS telescope), the research is not done with complete certainty. But the model shows 90% confidence that asteroids in the so-called “main belt” (between Mars and Jupiter”) experience disruptions in this way, at least once per year.

The research was published in the journal Icarus and is also available in preprint version on Arxiv. It was led by Larry Denneau at the University of Hawaii.

Source: Smithsonian Astrophysical Observatory

December 31, 2014December 23, 2015 by David Dickinson

10 Space Science Stories to Watch in 2015

A new Avengers movie. A reboot of the Star Wars franchise. The final installment of the Hunger Games. The Martian makes it to the big screen. Yup, even if the zombie apocalypse occurs in 2015, it’ll still be a great year. But trading science fiction for fact, we’re also on track for a spectacular year in space science and exploration as well.

Humanity will get its first good look at Ceres and Pluto, giving us science writers some new pics to use instead of the same half dozen blurry dots and artist’s conceptions. SpaceX will also attempt a daring landing on a sea platform, and long duration missions aboard the International Space Station will get underway. And key technology headed to space and on Earth may lead the way to opening up the window of gravitational wave astronomy on the universe. Here’s 10 sure-fire bets to watch for in the coming year from Universe Today:

10. LISA Pathfinder

A precursor to a full-fledged gravitational wave detector in space, LISA Pathfinder will be launching atop a Vega rocket from Kourou, French Guiana in July 2015. LISA stands for the Laser Interferometer Space Antenna, and the Pathfinder mission will journey to the L1 Lagrange point between the Earth and the Sun to test key technologies. LISA Pathfinder will pave the way for the full fledged LISA space platform, a series of three free flying spacecraft proposed for launch in the 2030s.

9. AdLIGO Goes Online

And speaking of gravitational waves, we may finally get the first direct detection of the same in 2015, when Advanced LIGO is set to go online. Comprised of two L-shaped detectors, one based in Livingston Louisiana, and another in Hanford Washington, AdLIGO will feature ten times the sensitivity of the original LIGO observatory. In fact, as was the case of the hunt for the Higgs-Boson by CERN, a non-detection of gravitational waves by AdLIGO would be a much stranger result!

8. Hubble Turns 25

Launched on April 24^th, 1990 aboard the Space Shuttle Discovery, the Hubble Space Telescope celebrates 25 years in space in 2015. The final servicing mission in 2009 gave Hubble a reprieve from the space junk scrap heap, and the orbiting telescope is still going strong. Hubble has no less than pushed the limits in modern astronomy to become a modern icon of the space age.

7. The End of MESSENGER

NASA’s Mercury exploring spacecraft wraps up its mission next year. Launched in 2004, MESSENGER arrived in orbit around Mercury after a series of flybys on March 18^th, 2011. MESSENGER has mapped the innermost world in detail, and studied the space environment and geology of Mercury. In late March 2015, MESSENGER will achieve one final first, when it impacts the surface of Mercury at the end of its extended mission.

6. Akatsuki at Venus

This Japanese spacecraft missed orbital insertion a few years back, but gets a second chance at life in 2015. Launched in 2010 atop an H-IIA rocket from the Tanegashima Space Center in Japan, Akatsuki failed to enter orbit around Venus at the end of 2010, and instead headed out for a heliocentric path around the Sun. Some quick thinking by JAXA engineers led to a plan to attempt to place Akatsuki in Venusian orbit in November 2015. This would be a first for the Japanese space agency, as attempts by JAXA at placing a spacecraft in orbit around another planet – including the Mars Nozomi probe – have thus far failed.

autonomous_spaceport_drone_ship — The target for the Falcon-9 first stage later next week. Credit: SpaceX.

5. SpaceX to Attempt to Land on a Sea Platform

It’ll definitely rock if they pull it off next week: on January 6^th, a SpaceX Falcon 9 rocket will lift off from Cape Canaveral with its Dragon spacecraft headed to the International Space Station on mission CRS-5. Sure, these resupply missions are becoming routine, but after liftoff, SpaceX is attempting something new and daring: landing the Falcon-9 first stage Buck Rodgers style, “fins first” on a floating barge. This is the next step in ultimately proving the feasibility of having the rocket fly back to the launch site for eventual reuse. If nothing else, expect some stunning video of the attempt soon!

4. NASA to Decide on an Asteroid Mission

Some major decisions as to the fate and the future of manned space exploration are due next year, as NASA is expected to decide on the course of action for its Asteroid Redirect Mission. The current timeline calls for the test of the SLS rocket in 2018, and the launch of a spacecraft to recover an asteroid and place it in orbit around the Moon in 2019. If all goes according to plan – a plan which could always shift with the political winds and future changes in administrations – we could see astronauts exploring a captured asteroid by the early 2020s.

Astronaut Scott Kelly (left), and cosmonaut Mikhail Korniyenko. Credit: NASA/Roscomos.

3. Long Duration ISS Missions

Beginning in 2015, astronauts and cosmonauts will begin year-long stays aboard the ISS to study the effects of long duration space missions. In March of 2015, cosmonaut Mikhail Korniyenko and U.S. astronaut Scott Kelly will launch as part of Expedition 43 headed to the ISS. The Russians have conducted stays in space longer than a year aboard the Mir space station, but Kelly’s stay aboard the ISS will set a duration record for NASA astronauts. Perhaps, a simulated “Mars mission” aboard the ISS could be possible in the coming years?

2. Dawn at Ceres

Fresh off of exploring Vesta, NASA’s Dawn spacecraft will become the first mission to enter orbit around a second object, the asteroid 1 Ceres next year in April 2015. The largest asteroid and the first object of its kind discovered on the first day of the 19^th century, Ceres looks to be a fascinating world in its own right. Does it possess water ice? Active geology? Moons of its own? If Dawn’s performance at Vesta was any indication, we’re in for another exhilarating round of space exploration!

1. New Horizons at Pluto

An easy No. 1,we finally get our first good look at Pluto in July, as NASA’s New Horizons spacecraft flies less than 14,000 kilometres from the surface of the distant world. Launched in 2006, New Horizons will “thread the needle” between Pluto and Charon in a flurry of activity as it passes by. New Horizons will then turn back as it passes into the shadows of Pluto and Charon and actually view the two worlds as they occult the distant Sun. And from there, New Horizons will head out to explore Kuiper Belt Objects of opportunity.

And these are just the top stories that are slated to be big news in space in 2015. Remember, another Chelyabinsk meteor or the next big comet could drop by at any time… space news can be unpredictable, and its doubtless that 2015 will have lots more surprises in store.

December 30, 2014December 23, 2015 by David Dickinson

Work Those Quads: Our Guide to the 2015 Quadrantid Meteors

Don't fear the moonlight... Credit and copyright: John Chumack.

Quick… what’s the only major meteor shower named after a defunct constellation? If you said the January Quadrantids, you’d be correct, as this often elusive but abrupt meteor shower is set to peak this coming weekend early in 2015.

And we do mean early, as in the night of January 3^rd going into the morning of January 4^th. This is a bonus, as early January means long dark nights for northern hemisphere observers. But the 2015 Quadrantids also has two strikes going against them however: first, the Moon reaches Full just a day later on January 5^th, and second, January also means higher than average prospects for cloud cover (and of course, frigid temps!) for North American observers.

Jan 4th 3AM local. Starry Night Education Software. — The rising radiant of the Quads on the morning of January 4th at 3AM local. Note that the Moon and Jupiter are on the scene as well. Created using Starry Night Education software.

Don’t despair, however. In meteor shower observing as in hockey, you miss 100% of the shots that you don’t take.

Sorry for the sports analogy. The radiant for the Quadrantids is located in the modern day constellation of Draco near the Hercules-Boötes border at a right ascension 15 hours, 18 minutes and declination +49.5 degrees north. This puts it very near the +3.3 magnitude star Iota Draconis (Edasich).

Quads 2UT. Credit: Orbitron — The orientation of the Earth’s shadow at the predicted peak of the Quads on January 4th, 2:00 UT. Credit: Orbitron.

In 2015, bets are on for the Quadrantids to peak centered on 2:00 UT January 4^th (9:00 PM EST on the 3rd), favoring northern Europe pre-dawn. The duration for the Quadrantids is short lived, with an elevated rate approaching 100 per hour lasting only six hours in duration. Keep in mind, of course, that it’ll be worth starting your vigil on Saturday morning January 3^rd in the event that the “Quads” kick off early! I definitely wouldn’t pass up on an early clear morning on the 3^rd, just in case skies are overcast on the morning of the 4^th…

Due to their high northern radiant, the Quadrantids are best from high northern latitudes and virtually invisible down south of the equator. Keep in mind that several other meteor showers are active in early January, and you may just spy a lingering late season Geminid or Ursid ‘photobomber’ as well among the background sporadics.

Avast: ye ole Mural Quadrant spied at the Columbia River Maritime Museum in Astoria, Oregon. Photo by author.

Moonset on the morning of the 4^th occurs around 6 AM local, giving observers a slim one hour moonless window as dawn approaches. Blocking the Moon out behind a building or hill when selecting your observing site will aid you in your Quadrantid quest.

The approximate realm of the “Mural Quadrant” overlaid on modern day constellations. Credit Stellarium.

Antonio Brucalassi made the first historical reference to the Quadrantids, noting that “the atmosphere was traversed by… falling stars” on the morning of January 2^nd, 1825. It’s interesting to note that the modern day peak for the Quads has now drifted a few days to the fourth, due mostly to the leap year-induced vagaries of our Gregorian calendar. The early January meteor shower was noted throughout the 19^th century, and managed to grab its name from the trendy 19^th century constellation of Quadrans Muralis, or the Mural Quadrant. Hey, we’re lucky that other also-rans, such as Lumbricus the ‘Earthworm’ and Officina Typograhica the ‘Printing Office’ fell to the wayside when the International Astronomical Union formalized the modern 88 constellations in 1922. Today, we know that the Quadrantids come from 2003 EH₁, which is thought to be an extinct comet now trapped in the inner solar system on a high inclination, 5.5 year orbit. Could 2003 EH₁ be related to the Great Comet of 1490, as some suggest? The enigmatic object reached perihelion in March of 2014, another plus in the positive column for the 2015 Quads.

What the heck is a Mural Quadrant? Like everything he did, Tycho Brahe super-sized his quadrant, depicted here. Credit: Wikimedia Commons.

Previous years for the Quadrantids have yielded the following Zenithal Hourly Rate (ZHR) maximums as per the International Meteor Organization:

2011= 90

2012= 83

2013= 137

2014= +200

The Quadrantid meteor stream has certainly undergone alterations over the years as a result of encounters with the planet Jupiter, and researchers have suggested that the shower may go the way of the 19^th century Andromedids and become extinct entirely in the centuries to come.

Don’t let cold weather deter you, though be sure to bundle up, pour a hot toddy (or tea or coffee, as alcohol impacts the night vision) and keep a spare set of batteries in a warm pocket for that DSLR camera, as cold temps can kill battery packs quicker than you can say Custos Messium, the Harvest Keeper.

And though it may be teeth-chatteringly cold where you live this weekend, we actually reach our closest point to the Sun this Sunday, as Earth reaches perihelion on January 4th at around 8:00 UT, just 5 hours after the Quads are expected to peak. We’re just over 147 million kilometres from the Sun at perihelion, a 5 million kilometre difference from aphelion in July. Be thankful we live on a planet with a relatively circular orbit. Only Venus and Neptune beat us out in the true roundness department!

…and no, you CAN’T defy gravity around perihelion, despite the current ill conceived rumor going ‘round ye ole net…

And as a consolation prize to southern hemisphere observers, the International Space Station reaches a period of full illumination and makes multiple visible passes starting December 30^th until January 3^rd. This happens near every solstice, with the December season favoring the southern hemisphere, and June favoring the northern.

2003 Credit and Copyright: Frankie Lucena. — A 2003 south bound Quad nabbed from Cabo Rojo, Puerto Rico (Yes, that’s the Southern Cross!) Credit and Copyright: Frankie Lucena.

So don’t let the relatively bad prospects for the 2015 Quadrantids deter you: be vigilant, report those meteor counts to the IMO, send those meteor pics in to Universe Today and tweet those Quads to #Meteorwatch. Let’s “party like it’s 1899,” and get the namesake of an archaic and antiquated constellation trending!

December 29, 2014December 23, 2015 by Tim Reyes

2015: NASA’s Year of the Dwarf Planet

Two spacecraft, Dawn and New Horizon will reach their final objectives in 2015 - Dwarf Planets - Ceres and Pluto. (Credit: NASA, Illustration - T.Reyes)

Together, the space probes Dawn and New Horizons have been in flight for a collective 17 years. One remained close to home and the other departed to parts of the Solar System of which little is known. They now share a common destination in the same year: dwarf planets.

At the time of these NASA probes’ departures, Ceres had just lost its designation as the largest asteroid in our Solar System. Pluto was the ninth planet. Both probes now stand to deliver measures of new data and insight that could spearhead yet another revision of the definition of planet.

A comparison of the trajectories of New Horizon (left) and the Dawn missions (right). (Credit: NASA/JPL, SWRI, Composite- T.Reyes) — A comparison of the trajectories of New Horizons (left) and the Dawn missions (right). (Credit: NASA/JPL, SWRI, Composite- T.Reyes)

Certainly, NASA’s Year of the Dwarf Planet is an unofficial designation and NASA representatives would be quick to emphasize another dozen or more missions that are of importance during the year 2015. However, these two missions could determine the fate of billions or more small bodies just within our galaxy, the Milky Way.

If Ceres and Pluto are studied up close – mission success is never a sure thing – then what is observed could lead to a new, more certain and accepted definition of planet, dwarf planet, and possibly other new definitions.

The New Horizons mission became the first mission of NASA’s New Frontiers program, beginning development in 2001. The probe was launched on January 19, 2006, atop an Atlas V 551 (5 solid rocket boosters plus a third stage). Utilizing more compact and lightweight electronics than its predecessors to the outer planets – Pioneer 10 & 11, and Voyager 1 & 2 – the combination of reduced weight, a powerful launch vehicle, plus a gravity assist from Jupiter has lead to a nine year journey. On December 6, 2014, New Horizons was taken out of hibernation for the last time and now remains powered on until the Pluto encounter.

This "movie" of Pluto and its largest moon, Charon b yNASA's New Horizons spacecraft taken in July 2014 clearly shows that the barycenter -center of mass of the two bodies - resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto's surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute) — This “movie” of Pluto and its largest moon, Charon, by NASA’s New Horizons spacecraft taken in July 2014 clearly shows that the barycenter – the center of mass of the two bodies – resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto’s surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

The arrival date of New Horizon is July 14, 2015. A telescope called the Long Range Reconnaissance Imager (LORRI) has permitted the commencement of observations while still over 240 million kilometers (150 million miles) from Pluto. The first stellar-like images were taken while still in the Asteroid belt in 2006.

Pluto was once the ninth planet of the Solar System. From its discovery in 1930 by Clyde Tombaugh until 2006, it maintained this status. In that latter year, the International Astronomical Union undertook a debate and then a membership vote that redefined what a planet is. The change occurred 8 months after New Horizons’ launch. There were some upset mission scientists, foremost of which was the principal investigator, Dr. Alan Stern, from the Southwest Research Institute in San Antonio, Texas. In a sense, the rug had been pulled from under them.

A gentleman’s battle ensued between opposing protagonists Dr. Stern and Dr. Michael Brown from Caltech. In 2001, Dr. Brown’s research team began to discover Kuiper belt objects (Trans-Neptunian objects) that rivaled the size of Pluto. Pluto suddenly appeared to be one of many small bodies that could likely number in the trillions within just one galaxy – ours. According to Dr. Brown, there could be as many as 200 objects in our Solar System similar to Pluto that, under the old definition, could be defined as planets. Dr. Brown’s work was the straw that broke the camel’s back – that is, it led to the redefinition of planet, and the native of Huntsville, Alabama, went on to write a popular book, How I Killed Pluto and Why It Had It Coming.

Dr. Stern’s story involving Pluto and planetary research is a longer and more circuitous one. Stern was the Executive Director of the Southwest Research Institute’s Space Science and Engineering Division and then accepted the position of Associate Administrator of NASA’s Science Mission Directorate in 2007. Clearly, after a nine year journey, Stern is now fully committed to New Horizons’ close encounter. More descriptions of the two protagonists of the Pluto debate will be included in a follow on story.

Artist’s concept depicting the Dawn spacecraft thrusting with its ion propulsion system as it travels from Vesta (lower right) to Ceres (upper left). The galaxies in the background are part of the Virgo supercluster. Dawn, Vesta and Ceres are currently in the constellation Virgo from the perspective of viewers on Earth. (Image credit: NASA/JPL) — Artist’s concept depicting the Dawn spacecraft thrusting with its ion propulsion system as it travels from Vesta (lower right) to Ceres (upper left). The galaxies in the background are part of the Virgo supercluster. Dawn, Vesta, and Ceres are currently in the constellation Virgo from the perspective of viewers on Earth. (Image credit: NASA/JPL)

The JPL and Orbital Science Corporation developed Dawn space probe began its journey to the main asteroid belt on September 27, 2007. It has used gravity assists and flew by the planet Mars. Dawn spent 14 months surveying Vesta, the 4th largest asteroid of the main belt (assuming Ceres is still considered the largest). While New Horizons has traveled over 30 Astronomical Units (A.U.) – 30 times the distance from the Earth to the Sun – Dawn has remained closer and required reaching a little over 2 A.U. to reach Vesta and now 3 A.U. to reach Ceres.

The Dawn mission had the clear objective of rendezvous and achieving orbit with two asteroids in the main belt between Mars and Jupiter. Dawn was also sent packing the next generation of Ion Propulsion. It has proven its effectiveness very well, having used ion propulsion for the first time to achieve an orbit. Pretty simple, right? Not so fast.

As Dawn was passing critical design reviews during development, the redefinition of planet lofted its second objective – the asteroid 1 Ceres – to a new status. While Pluto was demoted, Ceres was promoted from its scrappy status of biggest of the asteroids – the debris, the leftovers of our solar system’s development – to dwarf planet. Even 4 Vesta is now designated a proto-planet.

Artist rendition of Dawn spacecraft orbiting Vesta(Credit: NASA/JPL-Caltech) — Artist rendition of Dawn spacecraft orbiting Vesta. (Credit: NASA/JPL-Caltech)

So now the stage is set. Dawn will arrive first at a dwarf planet – Ceres – in April. With a small, low gravity body and ion propulsion, the arrival is slow and cautious. If the two missions fair well and achieve their goals, 2015 is likely to become a pivotal year in the debate over the classification of non-stellar objects throughout the universe.

Just days ago, at the American Geophysical Union Conference in San Francisco, Dr. Stern and team described the status and more details of the goals of New Horizons. Since arriving, more moons of Pluto have been discovered. There is the potential that faint rings exist and Pluto may even harbor an interior ocean due to the tidal forces from its largest moon, Charon. And Dawn mission scientists have seen the prospects for Ceres’ change. Not just the status, the latest Hubble images of Ceres is showing bright spots which could be water ice deposits and could also harbor an internal ocean.

The Solar System is becoming a more crowded place. This picture shows the sizes of dwarf planets Pluto, Ceres, Eris, and Makemake as compared to Earth and Earth's Moon, here called "Luna." None of the distances between objects are to scale. (Credit: NASA) — The Solar System is becoming a more crowded place. This picture shows the sizes of dwarf planets Pluto, Ceres, Eris, and Makemake as compared to Earth and Earth’s Moon, here called “Luna.” None of the distances between objects are to scale. (Credit: NASA)

So other NASA missions notwithstanding, this is the year of the dwarf planet. NASA will provide Humanity with its first close encounters with the most numerous of small round – by their self-gravity – bodies in the Universe. They are now called dwarf planets but ask Dr. Stern and company, the public, and many other planetary scientists and you will discover that the jury is still out.

References:

JHU/APL New Horizons Mission Home Page

NASA Dawn Mission Home Page