asteroid Archives

January 4, 2013December 23, 2015 by Jason Major

Ancient Impacts Stained Vesta with Carbon-Rich Material

Composite-color 3D image of Cornelia crater on Vesta (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Ever since arriving at Vesta in July 2011, NASA’s Dawn spacecraft has been capturing high-resolution images of the protoplanet’s surface, revealing a surprisingly varied and complex terrain covered in ridges, hills, grooves and, of course, craters of many different sizes and ages. Many of Vesta’s largest craters exhibit strange dark stains and splotches within and around them, some literally darker than coal. These stains were a puzzle to scientists when they were first seen, but the latest research now confirms that they may actually be the remains of the ancient impacts that caused them: dark deposits left by the myriad of carbon-rich objects that struck Vesta over the past four-and-a-half billion years.

Even though Vesta had a completely molten surface 4.5 billion years ago it’s believed that its crust likely solidified within a few million years, making the 530-km (329-mile) -wide world a literal time capsule for events taking place in the inner Solar System since then… one reason why Vesta was chosen as a target for the Dawn mission.

Using data acquired by Dawn during its year in orbit around Vesta, a team led by researchers from Germany’s Max Planck Institute for Solar System Research and the University of North Dakota investigated the dark material seen lining the edges of large impact basins located on the protoplanet’s southern hemisphere. What they determined was that much of the material was delivered during an initial large, low-velocity impact event 2–3 billion years ago that created the largest basin — Veneneia — and was then partially covered by a later impact that created the smaller basin that’s nearly centered on Vesta’s southern pole — Rheasilva.

“The evidence suggests that the dark material on Vesta is rich in carbonaceous material and was brought there by collisions with smaller asteroids.”

– Vishnu Reddy, lead author, Max Planck Institute for Solar System Research and the University of North Dakota

Dawn framing camera images of dark material on Vesta. (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Subsequent smaller asteroid impacts over the millennia likely brought more carbonaceous material to Vesta’s surface, both delivering it as well as revealing any that may have existed beneath brighter surfaces.

The dark, carbon-rich material observed on Vesta by Dawn also seems to match up with similarly dark clasts found in meteorites that have landed on Earth which are thought to have originated from Vesta.

“Our analysis of the dark material on Vesta and comparisons with laboratory studies of HED meteorites for the first time proves directly that these meteorites are fragments from Vesta,” said Lucille Le Corre from the Max Planck Institute for Solar System Research, another lead author of the study.

If evidence of such collisions between worlds can be found on Vesta, it’s likely that similar events were occurring all across the inner solar system during its early days, providing a clue as to how carbon-rich organic material was delivered to Earth — and possibly Mars as well. Such material — the dark stains we see today lining Vesta’s craters — would have helped form the very building blocks of life on our planet.

The team’s findings were published in the November/December issue of the journal Icarus.

Read more on the Max Planck Institute’s news page here, and on the NASA release here. Learn more about the Dawn mission in the video below, narrated by Leonard Nimoy.

January 1, 2013December 23, 2015 by Jason Major

New Study Shows Cosmic Rays Could Cause Alzheimer’s

Humans explore Mars in “Distant Shores,” an illustration by NASA artist Pat Rawlins

Cosmic rays from deep space could pose serious health risks to future astronauts on long-duration missions to Mars — even bringing on the memory-destroying symptoms of Alzheimer’s disease, according to the results of a new study from the University of Rochester Medical Center.

While NASA has its sights set on the human exploration of Mars within the next several decades, even with the best propulsion technology currently available such a mission would take about three years. Within that time, crew members would be constantly exposed to large amounts of radiation that we are protected from here by Earth’s magnetic field and atmosphere. Some of this radiation comes in the form of protons from the Sun and can be blocked by adequate spacecraft shielding materials, but a much bigger danger comes from heavy high-energy particles that are constantly whipping across the galaxy, shot out of the hearts of exploding giant stars.

“Because iron particles pack a bigger wallop it is extremely difficult from an engineering perspective to effectively shield against them. One would have to essentially wrap a spacecraft in a six-foot block of lead or concrete.”

– M. Kerry O’Banion, M.D., Ph.D.

While health risks from these high-mass, high-charged (HZE) particles have long been known, the exact nature of the damages they can cause to human physiology is still being researched — even more so now that Mars and asteroid exploration is on NASA’s short list.

Now, a team from the University of Rochester Medical Center (URMC) in New York has announced the results of their research linking high-energy radiation — just like what would be encountered during a trip to Mars — to the degeneration of brain function, and possibly even the onset of Alzheimer’s disease.

“Galactic cosmic radiation poses a significant threat to future astronauts,” said M. Kerry O’Banion, M.D., Ph.D., a professor in the University of Rochester Medical Center (URMC) Department of Neurobiology and Anatomy and the senior author of the study. “The possibility that radiation exposure in space may give rise to health problems such as cancer has long been recognized. However, this study shows for the first time that exposure to radiation levels equivalent to a mission to Mars could produce cognitive problems and speed up changes in the brain that are associated with Alzheimer’s disease.”

In particular the team focused on iron ions, which are blasted into space by supernovae and are massive enough to punch through a spacecraft’s protective shielding.

“Because iron particles pack a bigger wallop it is extremely difficult from an engineering perspective to effectively shield against them,” O’Banion said. “One would have to essentially wrap a spacecraft in a six-foot block of lead or concrete.”

By exposing lab mice to increasing levels of radiation and measuring their cognitive ability the researchers were able to determine the neurologically destructive nature of high-energy particles, which caused the animals to more readily fail cognitive tasks. In addition the exposed mice developed accumulations of a protein plaque within their brains, beta amyloid, the spread of which is associated with Alzheimer’s disease in humans.

“These findings clearly suggest that exposure to radiation in space has the potential to accelerate the development of Alzheimer’s disease,” said O’Banion. “This is yet another factor that NASA, which is clearly concerned about the health risks to its astronauts, will need to take into account as it plans future missions.”

While Mars explorers could potentially protect themselves from cosmic radiation by setting up bases in caves, empty lava tubes or beneath rocky ledges, which would offer the sort of physical shielding necessary to stop dangerous HZE particles, that would obviously present a new set of challenges to astronauts working in an already alien environment. And there’s always the trip there (and back again) during which time a crew would be very much exposed.

While this won’t — and shouldn’t — prevent a Mars mission from eventually taking place, it does add yet another element of danger that will need to be factored in and either dealt with from both health and engineering standpoints… or accepted as an unavoidable risk by all involved, including the public.

How much risk will be considered acceptable for the human exploration of Mars — and beyond? (NASA/Pat Rawlings)

Read more on the URMC news page here, and see the full experiment report here.

Illustrations for NASA by Pat Rawlings. See more of Rawling’s artwork here. Inset image: comparison of human brains without and with Alzheimer’s. Source: WHYY.

December 12, 2012December 23, 2015 by Nancy Atkinson

Asteroid Toutatis Tumbles by Earth: Images and Videos

Goldstone delay-Doppler radar images of Toutatis from December 11, 2012. Credit: NASA

While Asteroid 4179 Toutatis was never a threat to hit Earth during its quite-distant pass on Dec. 11-12, astronomers were keeping their instruments and eyes on this space rock to learn more about it, as well as learning more about the early solar system. Even at closest approach, 4179 Toutatis was 7 million km away or 18 times farther than the Moon. But that is close enough for radar imaging by NASA’s Goldstone Observatory, which has recently upgraded to a new digital imaging system, as well as optical imaging by other astronomers. Already, there are some preliminary findings from this 4.5-kilometer- long (3-mile-long) asteroid’s flyby.

“Toutatis appears to have a complicated internal structure,” said radar team member Michael Busch of the National Radio Astronomy Observatory. “Our radar measurements are consistent with the asteroid’s little lobe being ~15% denser than the big lobe; and they indicate 20% to 30% over-dense cores inside the two lobes.”

NASA says this raises the interesting possibility that asteroid Toutatis is actually a mash up of smaller space rocks. “Toutatis could be re-accumulated debris from an asteroid-asteroid collision in the main belt,” Busch said. The new observations will help test this idea.

Here are more images and video from Toutastis’ pass:

Adam Block from the Mount Lemmon SkyCenter/University of Arizona captured this footage:

Toutatis from Adam Block on Vimeo.

Astronomers are getting to know this asteroid, as it passes by Earth’s orbit every 4 years. It is one of the largest known potentially hazardous asteroids (PHAs), and its orbit is inclined less than half-a-degree from Earth’s. No other kilometer-sized PHA moves around the Sun in an orbit so nearly coplanar with our own. This makes it an important target for radar studies.

The team from the Remanzacco Observatory took this 120-second image of Toutatis:

Image from the ITelescope network (Nerpio, Spain) on 2012, Dec. 11.9, through a 0.15-m f/7.3 refractor + CCD. Credit: Ernesto Guido and Nick Howes/ Remanzacco Observatory.

And this was a fairly close pass for Toutatis: The next time Toutatis will approach at least this close to Earth is in November of 2069
when the asteroid will fly by at a distance of only 0.0198 AU (7.7 lunar distances).

NASA’s Goldstone radar in the Mojave Desert has been “pinging” the space rock every day starting on December 4, and will continue until the 22nd. The echoes highlight the asteroid’s topography and improve the precision with which researchers know the asteroid’s orbit.

Additionally, the Chinese Chang’e 2 spacecraft will be observing Toutatis tomorrow, on December 13, 2012 Chang’e 2 was originally launched to study the Moon but after completing its mission, Chang’e 2 departed from the L2 point in April 2012 to align itself to make a flyby of 4179 Toutatis, expected to take place at approximately 08:27 UTC on December 13.

“We already know that Toutatis will not hit Earth for hundreds of years,” said Lance Benner of NASA’s Near Earth Object Program.. “These new observations will allow us to predict the asteroid’s trajectory even farther into the future.”

Animation from Ernesto Guido and Nick Howes of 40 consecutive 10-second exposures. Credit: Ernesto Guido and Nick Howes/ Remanzacco Observatory.

NASA says the asteroid is already remarkable for the way that it spins. Unlike planets and the vast majority of asteroids, which rotate in an orderly fashion around a single axis, Toutatis travels through space “tumbling like a badly thrown football,” as Benner describes it. One of the goals of the radar observations is to learn more about the asteroid’s peculiar spin state and how it changes in response to tidal forces from the Sun and Earth.

Here’s an animation of Asteroid Toutatis compiled the live broadcast from the Slooh space camera team:

Goldstone delay-Doppler radar images of Toutatis from December 11, 2012. Credit: NASA

Sources: NASA, Remanzacco Observatory, Chang’e 2 mission

November 6, 2012December 23, 2015 by Jason Major

Say Hello to Asteroid 2007 PA8

Radar images of asteroid 2007 PA8 acquired on October 28, 29 and 30. (NASA/JPL-Caltech/Gemini)

Take a good look at asteroid 2007 PA8 — over the past week it was making its closest pass of Earth for the next 200 years… and NASA’s 230-foot (70-meter) -wide Deep Space Network antenna at Goldstone, California snapped its picture as it went by.

All right, maybe no “pictures” were “snapped”… 2007 PA8 is a small, dark body that only came within four million miles (6.5 million kilometers) today, Nov. 5 (0.043 AU, or 17 times the distance from Earth to the Moon). But the radar capabilities of the Deep Space Network antenna in California’s Mojave Desert can bounce radar off even the darkest asteroids, obtaining data that can be used to create a detailed portrait.

In the image above, a composite of radar data acquired on October 28, 29 and 30, we can see the irregular shape of 2007 PA8 as it rotates slowly — only once every 3-4 days. The perspective is looking “down” at the 1-mile (1.6-km) -wide asteroid’s north pole, showing ridges and perhaps even some craters.

Although classified as a Potentially Hazardous Asteroid (PHA) by the IAU’s Minor Planet Center the trajectory of 2007 PA8 is well understood. It is not expected to pose any impact threat to Earth in the near or foreseeable future.

2007 PA8 was discovered by LINEAR on August 9, 2007.

Read more about asteroid radar imaging here, and find out more about asteroids at JPL’s Asteroid Watch site here.

Get more information on the known properties of 2007 PA8 here.

Source: NASA Solar System Exploration. Image credits: NASA/JPL-Caltech/Gemini

September 28, 2012December 23, 2015 by Jason Major

Vesta’s Deep Grooves Could Be “Stretch Marks” From Impact

Dawn image of Vesta showing its nearly circumferential equatorial grooves (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Even though NASA’s Dawn spacecraft has departed Vesta the trove of data it’s gathered about this fascinating little world continues to fuel new discoveries. Most recently, some researchers are suggesting that Vesta’s curious grooves — long, deep troughs that wrap around its equator, noticed immediately after Dawn came within close proximity — are actually features called graben, the results of surface expansion along fault lines.

In Vesta’s case, the faults likely may have come from whatever major collision created the enormous central peak that rises almost three times the height of Mt. Everest from its south pole… and the expansion could be the result of differentiation of its interior — a separation of core, mantle and crust that’s much more planet-like than anything asteroidish.

On smaller asteroids and moons, stress fractures tend to have a “V” shape, cutting inwards to a sharp point. But the troughs on Vesta are more rounded, with a “U” shape that results from surface material slumping downwards as the surface pulls apart. Found on larger worlds like Earth, the Moon, Mars, Mercury — and now possibly Vesta as well — graben are shaped by motions below the crust and not just the splitting of the surface.

The biggest of Vesta’s troughs, Divalia Fossa, is 465 kilometers (289 miles) long, 22 km (13.6 mi) wide and 5 km (3 mi) deep… longer and three times deeper than the Grand Canyon.

Animation of Vesta rotating made from Dawn images and assembled by The Planetary Society’s Emily Lakdawalla

If the researchers are correct and these are indeed graben, rather than just fractures or grooves carved into the surface by another process, Vesta probably had a lot more going on inside it than does your typical asteroid.

“By saying it’s differentiated, we’re basically saying Vesta was a little planet trying to happen,” said Debra Buczkowski of the Johns Hopkins University Applied Physics Laboratory (JHUAPL), lead author of a new paper titled “Large-scale troughs on Vesta: A signature of planetary tectonics” scheduled to be published by the AGU on Sept. 29.

Unlike its big sister Ceres, the largest world among the asteroids and Dawn’s next destination, Vesta isn’t officially classified as a dwarf planet because its shape isn’t spherical enough — a flagrant violation of IAU Planetary Code Regulation No. 2. Rather it’s more flattened, like a walnut. This of course is also likely the result of the impact Vesta sustained at its south pole (which also may be responsible for its rapid 5.35-hour rotation rate, helping to bulge out the equatorial region and possibly even provide an alternate source for the trough “stretch marks”) and so begs the question, was Vesta once a dwarf planet? And if so, does severe reconstruction by an impact event “reclassify” it as something else? What, then? Ex-dwarf planet? A planet-formerly-known-as-dwarf?An undwarf?

I’m sure the IAU is already anticipating the contretemps.

“We have been calling Vesta the smallest terrestrial planet. The latest imagery provides much justification for our expectations. They show that a variety of processes were once at work on the surface of Vesta and provide extensive evidence for Vesta’s planetary aspirations.”

– Chris Russell, Dawn mission principal investigator at UCLA

Read more on the American Geophysical Union’s press release here, and follow the latest from NASA’s Dawn mission here.

June 15, 2012April 26, 2016 by Jason Major

Astronomers Measure Sunlight’s Shove

The physical force of sunlight on a moving asteroid has been measured by NASA scientists, providing information on how to better plot these Earth-passing worlds’ future paths.

First proposed by a 19-century Russian engineer, the Yarkovsky effect is the result of an object in space absorbing radiation from the Sun and emitting it as heat, thus creating a slight-but-measurable change in its movement (thanks to Newton’s first law of motion.)

By observing the 1999, 2005 and 2011 close passes of asteroid 1999 RQ36 with the Arecibo and Goldstone radar telescopes, astronomers were able to determine how much the trajectory of the half-kilometer-wide asteroid had changed.

The researchers’ findings revealed that RQ36 shifted by 160 km – about 100 miles – over the course of those 12 years. That deviation is attributed to the Yarkovsky effect. A miniscule force in and of itself, over time it has the ability to move entire worlds (albeit relatively small ones.)

“The Yarkovsky force on 1999 RQ36 at its peak, when the asteroid is nearest the Sun, is only about a half ounce — about the weight of three grapes on Earth,” said Steven Chesley of NASA’s Jet Propulsion Laboratory in Pasadena “Meanwhile, the mass of the asteroid is estimated to be about 68 million tons. You need extremely precise measurements over a fairly long time span to see something so slight acting on something so huge.”

Using measurements of the distance between the Arecibo Observatory in Puerto Rico and RQ36 during its latest pass in 2011 – a feat that was compared by team leader Michael Nolan to “measuring the distance between New York City and Los Angeles to an accuracy of two inches” – Chesley and his team were able to calculate all the asteroid’s near-Earth approaches closer than 7.5 million km (4.6 million miles) from the years 1654 to 2135. 11 such passes were found.

In addition, observation of 1999 RQ36 with NASA’s Spitzer Space Telescope found it to have about the same density as water – that’s light, for an asteroid.

Most likely, RQ36 is a “rubble-pile” form of asteroid, composed of a conglomeration of individual chunks of material held together by gravity.

These findings will be used by NASA scientists to help fine-tune the upcoming OSIRIS-REx mission, which is scheduled to launch in 2016 to rendezvous with 1999 RQ36 and return samples to Earth in 2023. Being a loose collection of rocks is expected to aid in the spacecraft’s sample retrieval process.

The findings were presented on May 19 at the Asteroids, Comets and Meteors 2012 meeting in Niigata, Japan. Read more here.

(Top image: series of radar images of asteroid 1999 RQ36 were obtained by NASA’s Deep Space Network antenna in Goldstone, Calif. on Sept 23, 1999. Credit: NASA/JPL-Caltech)

May 8, 2012April 26, 2016 by Jason Major

The Bright and Dark Side of Vesta’s Craters

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Bright craters, dark craters… craters shaped like butterflies… they’re all represented here in a panorama made from images acquired by NASA’s Dawn spacecraft, currently in orbit around the asteroid Vesta.

I stitched two images together (using a third for gap fill-in) that were originally acquired by Dawn’s framing camera in October 2011 and released last week. Because the angle of sunlight is pretty close to straight-on, there’s not a whole lot of relief in the original images so I bumped that contrast up a bit as well, to help bring out Vesta’s terrain.

The dark crater in the center is Laelia, and it’s surrounded by smaller dark impact craters as well… most notably one that displays dramatic rays of dark material. At top right is the much larger crater Sextilia, which has bright material revealed along its inner rim.

Near the lower left edge, just horizontal from Laelia, is the butterfly-shaped Helena crater. It shows both bright and dark material, the latter of which can be seen slumping into the crater as well as outward from its rim. Helena is approximately 22 kilometers (14 miles) in diameter. (There’s a scale at the lower right showing a 10-km / 6.2-mile-wide span.)

The images were acquired during the HAMO (high-altitude mapping orbit) phase of the mission.

On Thursday, May 10, NASA will host a news conference at 11 a.m. PDT (2 p.m. EDT) to present a new analysis of the giant asteroid Vesta using data from the agency’s Dawn spacecraft. The event will be broadcast live on NASA Television and streamed on the agency’s website. For streaming video, downlink and scheduling information visit: http://www.nasa.gov/ntv.

The event will also be streamed live on Ustream with a moderated chat available at http://www.ustream.com/nasajpl2. Questions may also be asked via Twitter using the hashtag #asknasa.The event will be held at NASA Headquarters in Washington, broadcast live on NASA Television and streamed on the agency’s website. For NASA TV streaming video, downlink and scheduling information, visit: http://www.nasa.gov/ntv.

Image credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA. Edited by J. Major.

609940main_pia15174-43_946-710 — This artist's concept shows NASA's Dawn spacecraft orbiting the giant asteroid Vesta. (NASA/JPL-Caltech)

March 6, 2012December 23, 2015 by Jason Major

Mexican Lake Bears Witness To Ancient Impact

Lake Cuitzeo in central Mexico. (Via Julio Marquez, Wikipedia Commons)

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Exotic sediments found beneath the floor of Lake Cuitzeo in central Mexico support theories of a major cosmic impact event 12,900 years ago, report a 16-member international research team. The impact may have caused widespread environmental changes and contributed to the extinctions of many large animal species.

Images of single and twinned nanodiamonds show the atomic lattice framework of the nanodiamonds. Each dot represents a single atom. (Source: UCSB release.)

The team found a 13,000-year-old layer of sediment that contains materials associated with impact events, such as soot, impact spherules and atomic-scale structures known as nanodiamonds. The nanodiamonds found at Lake Cuitzeo are of a variety known as lonsdaleite, even harder than “regular” diamond and only found naturally as the result of impact events.

The thin layer of sediment below Cuitzeo corresponds to layers of similar age found throughout North America, Greenland and Western Europe.

It’s thought that a large several-hundred-meter-wide asteroid or comet entered Earth’s atmosphere at a shallow angle 12,900 years ago, melting rocks, burning biomass and, in general, causing widespread chaos and destruction. This hypothesized event would have occurred just before a period of unusually cold climate known as the Younger Dryas.

The Younger Dryas has been associated with the extinction of large North American animals such as mammoths, saber-tooth cats and dire wolves.

“The timing of the impact event coincided with the most extraordinary biotic and environmental changes over Mexico and Central America during the last approximately 20,000 years, as recorded by others in several regional lake deposits,” said James Kennett, professor of earth science at UC Santa Barbara and member of the research team. “These changes were large, abrupt, and unprecedented, and had been recorded and identified by earlier investigators as a ‘time of crisis.’ ”

The exotic materials found in the sediment beneath Cuitzeo could not have been created by any volcanic, terrestrial or man-made process. “These materials form only through cosmic impact,” Kennett said.

The only other widespread sedimentary layer ever found to contain such an abundance of nanodiamonds and soot is found at the K-T boundary, 65 million years ago. This, of course, corresponds to the impact event that led to the extinction of the dinosaurs.

The researchers’ findings appeared March 5 in the Proceedings of the National Academy of Sciences. Read the news release from UC Santa Barbara here.

February 22, 2012December 24, 2015 by Jason Major

By Dawn’s Early Light

Vesta's surface textures get highlighted by dawn's light

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Sunrise on Vesta highlights the asteroid’s varied surface textures in this image from NASA’s Dawn spacecraft, released on Monday, Feb. 20. The image was taken on Dec. 18 with Dawn’s Framing Camera (FC).

Just as the low angle of early morning sunlight casts long shadows on Earth, sunrise on Vesta has the same effect — although on Vesta it’s not trees and buildings that are being illuminated but rather deep craters and chains of pits!

The steep inner wall of a crater is seen at lower right with several landslides visible, its outer ridge cutting a sharp line.

Chains of pits are visible in the center of the view. These features are the result of ejected material from an impact that occurred outside of the image area.

Other lower-profile, likely older craters remain in shadow.

Many of these features would appear much less dramatic with a high angle of illumination, but they really shine brightest in dawn’s light.

See the full image release on the Dawn mission site here.

Image credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA

January 30, 2012December 24, 2015 by Jason Major

Help Astronomers Measure the Solar System!

The orbit of asteroid 433 Eros brings it close to Earth on Jan. 31. (www.astronomerswithoutborders.org)

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As the bright Mars-crossing asteroid 433 Eros makes its closest approach to Earth since 1975, astronomers around the globe are taking the opportunity to measure its position in the sky, thereby fine-tuning our working knowledge of distances in the solar system. Using the optical principle of parallax, whereby different viewpoints of the same object show slightly shifted positions relative to background objects, skywatchers in different parts of the world can observe Eros over the next few nights and share their images online.

The endeavor is called the Eros Parallax Project, and you can participate too!

eros2012-chart — 433 Eros' path from jan. 30 - Feb. 1, 2012. (transitofvenus.nl)

Discovered in 1898, Eros was the largest near-Earth asteroid yet identified. Its close and relatively bright oppositions were calculated by astronomers of the day and used, along with solar transits by Venus (one of which, if you haven’t heard, will also occur this year on June 5!) to calculate distances in the inner solar system.

Having both events take place within the same year offers today’s astronomers an unparalleled opportunity to obtain observational measurements.

Through the efforts of the Astronomers Without Borders organization, along with Steven van Roode and Michael Richmond from the Transit of Venus project, anyone with moderate astrophotography experience can participate in the observation of Eros and share their photos via free online software.

Using the data gathered by individual participants positioned around the world, each with their own specific viewpoints, astronomers will be able to precisely measure the distance to Eros.

The more accurately that distance is known, the more accurately the distance from Earth to the Sun can be calculated – via the orbital mechanics of Kepler’s third law.

eros-tumbling — The tumbling motion of elongated 33-km-long Eros creates a changing brightness. (via transitofvenus.nl)

The last time such a bright pass of Eros occurred was in January of 1931. Observations of the asteroid made at that time allowed astronomers to calculate a solar parallax of 8″ .790, the most accurate up to that time and the most accurate until 1968, when data acquired by radar measurements gave more detailed measurements.

In many ways the 2012 close approach by Eros – astronomically close, but still a very safe 16.6 million miles (26.7 million km) away – will allow for a re-eneactment of the 1931 event… with the exception that this time amateur skywatchers will also contribute data, instantly, from all over the world!

One has to wonder…when Eros comes this close again in 2056, what sort of technology will we use to watch it then…

Find out more about the Eros Parallax Project and how to participate here.

And be sure to check out the article about the project on Astronomers Without Borders as well.