Posted on by Jason Major

Red Suns and Black Trees: Shedding a New Light on Alien Plants

 

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The grass may definitely not be greener on some alien worlds, suggests a new study from the UK. For example, planets in double-star systems could have grey or black vegetation.

Researcher Jack O’Malley-James of the University of St Andrews in Scotland worked out how photosynthesis in plants is affected by the color of the light they receive. On Earth, most plants have evolved to be green in order to take advantage of the yellowish color of the sunlight that’s received on the surface of our planet. (Our Sun, classified as a “Population I yellow dwarf star”, would look bright white from space but our atmosphere makes it appear yellow.) There are lots of other stars like our Sun in the Universe, and many of them are in multiple systems sharing orbits with other types of stars…red dwarfs, blue stars, red giants, white dwarfs…stars come in many different colors depending on their composition, age, size and temperature. We may be used to yellow but nature really has no preference! (Although red dwarfs happen to be the garden variety star in our own galaxy.)

Terrestrial examples of dark-colored plants

Planets that orbit within these multiple systems and exist within the habitable “Goldilocks” zone (and we are finding more and more candidates every day!) could evolve plants that depend on suns with different colors than ours. Green does a good job powering photosynthesis here, but on a planet orbiting a red dwarf and Sun-like star plants could very well be grey or black to absorb more light energy, according to O’Malley-James.

“Our simulations suggest that planets in multi-star systems may host exotic forms of the more familiar plants we see on Earth. Plants with dim red dwarf suns for example, may appear black to our eyes, absorbing across the entire visible wavelength range in order to use as much of the available light as possible.”

– Jack O’Malley-James, School of Physics and Astronomy, University of St Andrews

The study takes into consideration many different combinations of star varieties and how any potential life-sustaining planets could orbit them.

In some instances different portions of a planet may be illuminated by a differently-colored star in a pair…what sorts of variations in plant (and subsequently, animal) evolution could arise then?

And it’s not just the colors of plants that could evolve differently. “For planets orbiting two stars like our own, harmful radiation from intense stellar  flares could lead to plants that develop their own UV-blocking sunscreens, or photosynthesizing microorganisms that can move in response to a sudden flare,” said O’Malley-James.

Kermit may have been right all along…being green might really not be easy!

Read more on the Royal Astronomical Society’s news release or on the University of St Andrews website.

Top image credit: Jason Major

Posted on by Nancy Atkinson

Launch Date Set for Particle Detector Mission; Endeavour’s Final Flight,

Launch sign at Kennedy Space Center counts down the days to the STS-134 launch of shuttle Endeavour. Photo credit: NASA/KSC › Larger Image

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The launch date for the long-awaited Alpha Magnetic Spectrometer-2 (AMS) to the International Space Station has been set for Friday, April 29, at 3:47 p.m. EDT on from NASA’s Kennedy Space Center in Florida. The 14-day STS-134 mission is shuttle Endeavour’s final scheduled flight. After a flight readiness review today, NASA and contractor managers determined the shuttle and station’s equipment, support systems and personnel are ready to go.

The other notable aspect of the mission is that Mark Kelly is commanding, and his wife, Representative Gabrielle Giffords is tentatively expected to attend the launch, just months after she was shot in the head. This certainly will bring a unique aspect to the launch, at least for the media coverage, drawing attention to the mission to those who might not normally take notice.

For those who always pay attention to shuttle missions, however, two aspects make this mission noteworthy: the AMS and Endeavour’s final mission. The mission will also feature the last four spacewalks by a shuttle crew.

The AMS is designed to measure cosmic rays to search for various types of unusual matter, such as dark matter and antimatter. The instrument’s experiments will help researchers study the formation of the universe.

Professor Sam Ting, AMS Principal Investigator, with the AMS in the background. Credit: Chase Clark.

Also during the flight, Endeavour also will deliver the Express Logistics Carrier 3, a platform that carries spare parts to sustain station operations after the shuttles are retired from service. During the scheduled spacewalks, astronauts will do maintenance work, install new components, and perform a complex series of tasks to top off the ammonia in one of the station’s photovoltaic thermal control system cooling loops.

The crew consists of Kelly, Pilot Greg H. Johnson, NASA Mission Specialists Michael Fincke, Andrew Feustel and Greg Chamitoff and European Space Agency Mission Specialist Roberto Vittori. They are scheduled to arrive at Kennedy on Tuesday, April 26, for final launch preparations.

STS-134 is the 134th shuttle mission, Endeavour’s 25th flight and the 36th shuttle mission to the station.

Universe Today will be on hand live to cover the launch from Kennedy Space Center, and provide updates as the mission progresses.

Posted on by Nancy Atkinson

Gallery: 10 Years of Canadarm2, Construction Crane in Space

Canadarm2, the huge robotic arm on the International Space Station holds astronaut Stephen Robinson during the STS-114 mission. Credit: NASA

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On April 19, 2001, space shuttle Endeavour’s STS-100 mission launched to the space station, and in the payload bay was Canadarm2, a larger, more robust successor to the shuttle’s Canadarm. The Space Station Remote Manipulator System (SSRMS) is a sophisticated “construction crane,” and is responsible for much of the successful building of the ISS — module by module — in space.

“She is without a doubt one of the most critical components on board station having participated in the construction of the spacecraft that is on orbit today,” said Mike Suffredini, Program Manager of the International Space Station. “Twenty-nine missions have been supported by Canadarm2, two of them capturing and berthing the HTV vehicle, and in all that time with absolutely flawless performance. Without her we couldn’t have gotten to where we are today.”

See a gallery of images of Canadarm2’s 10 years in the space construction business.


April 22, 2001 – History is made. Canadian Space Agency Astronaut Chris Hadfield, attached to Canadarm, installs the next-generation Canadarm2 to the International Space Station during Shuttle Mission STS-100. Credit: NASA

Canadarm2 was installed on the ISS by astronaut Chris Hadfield during the first spacewalk by a Canadian. Canadarm2 has unloaded hundreds of tons of equipment and supplies ferried by the shuttle and assisted almost 100 spacewalks. Endeavour’s last flight later this month will mark Canadarm2’s 28th Shuttle mission.

July 15, 2001 – Canadarm2 performs its first official task, attaching the Quest Airlock to the Unity module of the International Space Station during Shuttle Mission STS-104. Credit: NASA

The Canadian Space Agency says that Canadarm2’s role on the ISS will expand as the orbital lab nears completion: in addition to performing routine maintenance, the robotic arm will make more frequent “cosmic catches,” where it will capture, dock and later release visiting spacecraft, as it has done with the HTV. When the space shuttle retires, reusable commercial spacecraft, like SpaceX’s Dragon and Orbital’s Cygnus, will be used to bring supplies and equipment to the ISS. Canadarm2 will capture each of these visiting vehicles. In late 2011 and early 2012, Canadarm2 will capture a series of 6 commercial spacecraft in just 7 months, beginning with the Dragon spacecraft, currently scheduled to arrive in October 2011.

How the ISS looked back in 2001, with Canadarm2 showing prominently. Credit: NASA
June 15, 2007 – Shuttle Mission STS-117 continued assembly operations that featured more work on the Station’s solar arrays. In this image, NASA astronaut Jim Reilly, attached to Canadarm2, and NASA colleague John “Danny” Olivas, are folding up an older solar panel so that it can be stowed and moved to another location on a future shuttle mission. Credit: NASA
November 3, 2007 – Canadarm2 played a big role in helping astronauts fix a torn solar array. The arm’s reach was extended by the Orbiter Boom Sensor System, and here, allowing astronaut Scott Parazynski analyses the solar panel while anchored to the boom. Credit: NASA
February 12, 2008 – Here, Canadarm2 has a firm grip on the European Space Agency’s Columbus module, which it grappled and attached to the station. Credit: NASA

More info on the SSRMS and how it was built:

The Expedition 27 crew on board the ISS pay tribute to 10 years of the SSRMS:

See more images and info at CSA’s website.

Posted on by Nancy Atkinson

Latest Images from Mercury: Bright Peaks, Swirling Craters and Weird Terrain

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

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The MESSENGER spacecraft is still happily orbiting Mercury since its orbit insertion in mid-March, and here are some of the latest images sent back from the first rock from the Sun. In this image, the central peaks inside a large crater named Asvaghosa show up as exceptionally bright. The MESSENGER team believes that their high reflectance appears to have been enhanced by the crater rays that cross the area, which originates from another crater. Asvaghosa is 90 km (56 mi.) in diameter, and was targeted for special, high-resolution observations, where MESSENGER’s cameras zero-in for the closest looks possible. While it is not possible to cover all of Mercury’s surface at this high of a resolution during the spacecraft’s one-year mission, several areas of high scientific interest are generally imaged in this mode each week.

See more below!

Oblique view of Bek crater on Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

What a unique, swirling crater — and this high-resolution view of Bek crater (32 km (20 miles) in diameter) has me trying to imagine scaling the cliffs seen in this incredible vista. The MESSENGER team says that the sharp crater rim is in contrast to its subdued surroundings, where crater ejecta scoured the surface and left behind many secondary craters.

'Weird terrain' inside the crater Petrarch on Mercury. Credit: Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

When scientists from the Mariner 10 team first saw this region around Petrarch crater, they called it “weird terrain.” The rugged terrain has an unusual “hilly and lineated” that may have been modified by converging seismic waves and/or ejecta from the formation of the Caloris basin, which is located on the opposite side of the planet. Now, MESSENGER viewed this area under differing lighting conditions than those seen during MESSENGER’s second flyby and Mariner 10’s first pass. The large, smooth area in the upper left is the floor of Petrarch.

See more of the latest images from MESSENGER on the mission’s gallery on their website.

Posted on by Ken Kremer

Yuri Gagarin From the Earth to Mars Tribute

The legacy of Yuri Gagarin and Vostok1 honored by Opportunity Mars Rover at Vostok Crater and Gagarin Rock. Photos: Roscosmos/NASA/JPL Poster: Ken Kremer

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50 Years ago, the dream of human spaceflight opened with the courageous blastoff of Cosmonaut Yuri Gagarin inside the Vostok 1 spacecraft on April 12, 1961. Gagarin was the first person to orbit the Earth. Less than a month later on May 5. 1961, Astronaut Alan Shepard bravely set forth on America’s first human spaceflight – Freedom 7.

Barely three weeks afterward on May 25, 1961, these momentous events of the early Space Age led directly to Project Apollo and the historic announcement by President Kennedy that the United States “would land a man on the moon” by the end of the 1960’s.

In honor of Yuri Gagarin, NASA’s Opportunity Mars Rover explored a small and highly eroded crater dubbed “Vostok Crater” in 2005 during its journey in the Meridian Planum region on the Martian surface. Along the edge of the crater, researchers commanded Opportunity to use the Rock Abrasion Tool (RAT), to drill into a rock dubbed “Gagarin” on Sols 401 and 402 in March 2005.

Yuri Gagarin - first human in space. Credit: Russian Archives

I created the poster collage above as a tribute to the first human spaceflight by Yuri Gagarin and his legacy which eventually led to the exploration of Mars by the Spirit and Opportunity rovers

Opportunity landed on Mars on Jan. 24, 2004 for a planned 90 sol mission. By the time that Opportunity arrived at Vostok Crater, she had already lasted more than 4 times longer than expected and found that water existed on ancient Mars.

Opportunity is still alive today on Sol 2571, more than 28 times beyond its design lifetime !

Opportunity used its rock abrasion tool (RAT) on a rock named "Gagarin" during Sols 401 and 402 on Mars (March 10 and 11, 2005). This false-color image shows the circular mark created where the tool exposed the interior of the rock Gagarin at a target called "Yuri." The circle is about 4.5 centimeters (1.8 inches) in diameter. Gagarin is at the edge of a highly eroded, small crater that was named "Vostok" for the spacecraft that carried Cosmonaut Yuri Gagarin in the first human spaceflight, on April 12, 1961. This image combines exposures taken through three different filters by Opportunity's panoramic camera on Sol 405 (March 14, 2005). Credit: NASA/JPL-Caltech/Cornell Univ./ASU

Scientists are using the data gathered from “Gagarin Rock” and other locations explored by Opportunity to help elucidate the history of the past flow of liquid water on the red planet and determine whether the wet environmental conditions could ever have supported martian microbial life – past or present.

“The 50th anniversary of mankind’s first fledgling foray into the cosmos should serve as an important reminder of the spirit of adventure and exploration that has propelled mankind throughout history,” said Mars rover science team member James Rice of NASA Goddard Space Flight Center, Greenbelt, Md, in a statement. “We are a species of explorers; it is encoded into our very DNA.”

“Half a century ago Yuri Gagarin was lofted into a totally unknown, remote and hostile environment and in doing so opened up a new limitless frontier of possibilities for mankind,” Rice added. “A mere 23 days later another brave human, Alan Shepard, climbed aboard a rocket and ventured into the starry abyss. Their courage and vision continue to inspire and lead us into the unknown. Hopefully, one day in the not too distant future it will lead humanity on a voyage to Mars.”

Many people, including myself, were inspired by the Space Race to become scientists and engineers and hope that continues for the next generation of students today.

Read more about Yuri Gagarin and Opportunity in my related stories:

Yuri Gagarin and Vostok 1 Photo Album – 50th Anniversary of Human Spaceflight
Countdown to Yuri’s Night and the 50th Anniversary of Human Spaceflight !
Stirring Video Tributes to Yuri Gagarin
Opportunity Rover Completes Exploration of fascinating Santa Maria Crater

Opportunity used its rock abrasion tool on a rock named "Gagarin" during the 401st and 402nd Martian days, or sols, of the rover's work on Mars (March 10 and 11, 2005). This image, taken by Opportunity's navigation camera on Sol 405 (March 14, 2005), shows the circular mark left on the rock. The circle is about 4.5 centimeters (1.8 inches) in diameter. At the end of the rover's arm, the tool turret is positioned with the rock abrasion tool pointing upward in this image. The abrasion target on the rock Gagarin was informally named "Yuri." Credit: NASA/JPL-Caltech
Opportunity Traverse Map during 7 year long journey across Mars.
Map shows the long journey of Opportunity spanning the Meridiani Planum region from landing in Jan 2004 to recent stop at Santa Maria crater. Opportunity explored Vostok Crater in March 2005, about 1 year after landing as indicted by marker in yellow. Credit: NASA/JPL/Cornell Marco Di Lorenzo, Kenneth Kremer
Posted on by Jason Major

Is Titan Hiding an Ocean?

Titan holds yet more secrets, far beneath its haze...

 

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Saturn’s moon Titan just keeps throwing surprises at us. A multi-layered atmosphere thicker than our own? Check. A hydrologic cycle that relies on methane as the operating liquid? Check. Rivers, streams and lakes filled with this same liquid? Check, check and check. And now, scientists are suspecting that Titan may have yet another surprise: a subsurface ocean.

Observations of Titan’s rotation and orbit, carried out by researchers at the Royal Observatory of Belgium using Cassini data, point at an unusual rotational inertia; that is, its resistance to changes in its motion, also known as moment of inertia or angular mass. Basically Titan moves in a way that is not indicative of a solid body of its previously assumed density and mass. Rather, its motion – both around its own axis and in its tidally-locked orbit around Saturn – are more in line with an object that isn’t uniformly solid.

Titan's thick clouds hide its surface well. NASA / JPL / SSI / J.Major

According to the math, Titan may very well be filled with liquid!

Or, at least, have a liquid layer of considerable depth beneath its surface. How far below the surface, how deep and exactly what kind of liquid are all speculative at this point…it’s suggested that it may be a subsurface ocean of yet more methane. This would help answer the question of where Titan gets all of its methane in the first place; methane, – a.k.a. natural gas – is a compound that breaks down quickly in sunlight. In fact, the high-level haze that surrounds the moon like a wispy blue shell is made up of this broken-down methane. So if this stuff is raining down onto the surface in giant, frigid drops and filling streams and lakes, but is still being broken down by ultraviolet light from the Sun to enshroud the entire moon (Titan is BIG, remember…at 5,150 km – 3,200 miles – wide, it’s over a third the size of Earth!) then there has to be somewhere that this methane is coming from.

If these calculations are right, it may be coming from underground.

We propose a new Cassini state model for Titan in which we assume the presence of a liquid water ocean beneath an ice shell… with the new model, we find a closer agreement between the moment of inertia and the rotation state than for the solid case, strengthening the possibility that Titan has a subsurface ocean.

– Rose-Marie Baland et al.

Of course in order for this hypothesis to be proven many more numbers are going to have to be crunched and more data reviewed. And more possibilities considered, too; Titan’s orbital irregularities may in fact be the result of external forces, such as a close pass by a comet or other large body. Still, there’s something to be investigated here and you can bet there’ll be no shortage of attention on a problem as intriguing as this!

Titan may soon be joining the short list of moons speculated to possess subsurface oceans, alongside Jupiter’s Europa and Ganymede and sister Saturnian satellite Enceladus…and who knows how many others?

Read the article on MIT’s Physics arXiv Blog, or you can download the full report here.

Top image credit: NASA / JPL / SSI. (Edited by J. Major.)

Posted on by Jason Rhian

NASA Announces Awardees of CCDev2

SpaceX was one of four companies whose proposals were selected as part of the Commercial Crew Development 2 (CCDev2) contract. Image Credit: SpaceX

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NASA has announced the winners of the four second-round agreements under the Commercial Crew Development (CCDev2) program. These companies will now be awarded between $22 million and $92 million for their proposals. These funds will be used to help the winning commercial firms to develop and improve their concepts for bringing NASA astronauts to space.

These concepts cover both launch vehicles and the spacecraft that ride on them. NASA has selected Blue Origin and granted them $22 million, Sierra Nevada Corporation with $80, Space Exploration Technologies (SpaceX) with $75 million and Boeing with $92.3 million.

SpaceX said via Twitter that they will be ready to fly the first manned mission three years after receiving these new funds.

Sierra Nevada Corporation's Drewm Chaser was the only shuttle shaped spacecraft selected, the other two proposals selected were capsules. Image Credit: SNC

“The next American-flagged vehicle to carry our astronauts into space is going to be a U.S. commercial provider,” said Ed Mango, NASA’s Commercial Crew Program manager. “The partnerships NASA is forming with industry will support the development of multiple American systems capable of providing future access to low-Earth orbit.”

The CCDev initiative was started back in 2009 with the intent of jump-starting the aerospace community into expanding U.S. spaceflight capabilities. CCDev2 is designed to speed up this process and reduce the gap in the nation’s human spaceflight abilities (when space shuttle Atlantis completes its final mission this summer, the U.S. will essentially lose the ability to send astronauts into orbit).

Established aerospace company Boeing submitted and was one of four that one with its capsule-shaped proposal. Image Credit: Boeing

CCDev2 saw an explosion of proposals for a variety of spacecraft, SpaceX, Orbital Sciences, Boeing, Blue Origin, Alliant Techsystems and Sierra Nevada all submitted ideas. It is hoped that new space markets might arise out of this project which could see an expansion of customers – both commercial and government.

“We’re committed to safely transporting U.S. astronauts on American-made spacecraft and ending the outsourcing of this work to foreign governments,” said NASA Administrator Charles Bolden. “These agreements are significant milestones in NASA’s plans to take advantage of American ingenuity to get to low-Earth orbit, so we can concentrate our resources on deep space exploration.”

In an effort to keep the shuttles flying for a while longer, United Space Alliance (USA) entered their own proposal for CCDev2 - the space shuttle. Photo Credit: Jason Rhian

A wide range of both established and new space companies entered submissions. Utah’s Alliant Techsystems (ATK) had proposed Liberty, a partnership between them and the European space company Astrium (the producers of the Ariane rocket). Orbital Sciences entered a mini space shuttle and United Space Alliance (USA) entered a proposal that would have seen the space shuttles Endeavour and Atlantis continue to fly under the rebranded Commercial Space Transportation System.

Posted on by Nancy Atkinson

Carnival of Space #193

A brand new Carnival of Space, hosted by The Robot Guy!

Click here to read the Carnival of Space #193.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host; send an email to the above address.

Posted on by Jason Major

Kepler Discovers a Rare Triple Gem

Animation of HD 181068 (click to play)

 

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It may be visible to the naked eye, but it took the unblinking gaze of NASA’s Kepler space telescope to reveal the true triple nature of this star system.

Animation of HD 181068 (click to play)

Unofficially dubbed “Trinity”, object HD 181068 is a multiple star system comprised of three stars: a red giant more than twelve times the diameter of the Sun and two red dwarf stars each slightly smaller than the Sun. The red dwarfs orbit each other in tight rotation around a central point, which in turn orbits the red giant. The smaller stars complete a full orbit around the giant every 45.5 days and, from our point of view, pass directly in front of and behind the huge star.

The orbital eclipse events of HD 181068 last about 2 days. What’s surprising is that during these eclipses the brightness of the system is not affected very much. This is because the surface brightnesses of the three stars are very similar. The current metaphor is a “white rabbit in a snowfall”, wherein the two red dwarfs effectively become invisible when they pass in front of the red giant. It wasn’t until the Kepler mission that we had an observational tool precise enough to detect the structure of this intriguing star system, located 800 light-years away from our own.

“The intriguing nature of this unique system remained unnoticed until now despite the fact that it is nearly bright enough to be visible to the naked eye. We really needed Kepler with its unprecedentedly precise and uninterrupted photometric monitoring to uncover such a rare gem.”

– Aliz Derekas, Eotvos University and Konkoly Observatory, Budapest, Hungary

Another unexpected feature of Trinity is its “quiet” nature. Astronomers have known that red giant stars exhibit seismic oscillations, as does our own Sun. But these oscillations are not present in Trinity’s red giant. Scientists speculate that the two red dwarfs may be creating some sort of gravitational offset, effectively negating the red giant’s vibrations. More research will be needed to determine if this is in fact the case.

Find out more about HD 181068 and other recent Kepler discoveries on NASA’s mission site or in the press release issued by the Ames Research Center, or read the published report on Science.

Image credit: NASA/KASC

 

 

Posted on by Vanessa Janek

Antigravity Could Replace Dark Energy as Cause of Universe’s Expansion

Annihilation
Illustration of Antimatter/Matter Annihilation. (NASA/CXC/M. Weiss)

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Since the late 20th century, astronomers have been aware of data that suggest the universe is not only expanding, but expanding at an accelerating rate. According to the currently accepted model, this accelerated expansion is due to dark energy, a mysterious repulsive force that makes up about 73% of the energy density of the universe. Now, a new study reveals an alternative theory: that the expansion of the universe is actually due to the relationship between matter and antimatter. According to this study, matter and antimatter gravitationally repel each other and create a kind of “antigravity” that could do away with the need for dark energy in the universe.

Massimo Villata, a scientist from the Observatory of Turin in Italy, began the study with two major assumptions. First, he posited that both matter and antimatter have positive mass and energy density. Traditionally, the gravitational influence of a particle is determined solely by its mass. A positive mass value indicates that the particle will attract other particles gravitationally. Under Villata’s assumption, this applies to antiparticles as well. So under the influence of gravity, particles attract other particles and antiparticles attract other antiparticles. But what kind of force occurs between particles and antiparticles?

To resolve this question, Villata needed to institute the second assumption – that general relativity is CPT invariant. This means that the laws governing an ordinary matter particle in an ordinary field in spacetime can be applied equally well to scenarios in which charge (electric charge and internal quantum numbers), parity (spatial coordinates) and time are reversed, as they are for antimatter. When you reverse the equations of general relativity in charge, parity and time for either the particle or the field the particle is traveling in, the result is a change of sign in the gravity term, making it negative instead of positive and implying so-called antigravity between the two.

Villata cited the quaint example of an apple falling on Isaac Newton’s head. If an anti-apple falls on an anti-Earth, the two will attract and the anti-apple will hit anti-Newton on the head; however, an anti-apple cannot “fall” on regular old Earth, which is made of regular old matter. Instead, the anti-apple will fly away from Earth because of gravity’s change in sign. In other words, if general relativity is, in fact, CPT invariant, antigravity would cause particles and antiparticles to mutually repel. On a much larger scale, Villata claims that the universe is expanding because of this powerful repulsion between matter and antimatter.

What about the fact that matter and antimatter are known to annihilate each other? Villata resolved this paradox by placing antimatter far away from matter, in the enormous voids between galaxy clusters. These voids are believed to have stemmed from tiny negative fluctuations in the primordial density field and do seem to possess a kind of antigravity, repelling all matter away from them. Of course, the reason astronomers don’t actually observe any antimatter in the voids is still up in the air. In Villata’s words, “There is more than one possible answer, which will be investigated elsewhere.” The research appears in this month’s edition of Europhysics Letters.