New findings on dark energy back discarded Einstein theory

Scientists have found that dark energy, the force thought to be accelerating the expansion of the universe, may be doing the same thing to local groups of galaxies. That bolsters Einstein's idea of a 'cosmological constant.'

This Dec. 16, 2008 file photo, shows the galaxy cluster Abell 85, located about 740 million light years from Earth. Galaxy clusters are the largest collapsed objects in the Universe and are ideal for studying the properties of dark energy, the mysterious form of repulsive gravity that is driving the accelerated expansion of the Universe.

Ten years ago, astronomers made the stunning discovery that the universe is expanding at a faster rate than it should, given the amount of matter the cosmos contains. Scientists named the driving force behind the unexpected acceleration dark energy.

Now a team of astronomers is reporting observations showing that this mysterious force not only works on cosmic scales spanning billions of light years. It's also affecting members of the Milky Way's local group of galaxies.
That strongly suggests that dark energy's effects are constant over time and space, arguing in favor of Albert Einstein's original notion of a cosmological constant that prevented the universe from ultimately collapsing under its own gravity, the team says. Einstein ultimately discarded the idea as his biggest blunder.
In principle, mutual gravity binds the 30-odd galaxies in the Milky Way’s local group together. But the team found that dark energy is driving the group's most distant galaxies away from the group, in the same way it does on vastly larger scales.
"We have an outflow that is consistent on the scale of millions of light years with the value of the dark energy that's obtained by studying galaxies billions of light years away," says University of Alabama astronomer Gene Byrd, a member of the team. He described the results at a briefing today at the American Astronomical Society's winter meeting in Washington.

Einstein's 'blunder'

Einstein was convinced the universe was static, neither expanding nor contracting. Yet his theory of general relativity implied that gravity from all the matter in the universe should cause it to contract. So he introduced the idea of a cosmological constant, a repulsive force that canceled out the contraction. He later discarded the in large part because astronomer Edwin Hubble discovered that the universe was in fact expanding and not static.
With the discovery of dark energy in 1998 and 1999, however, the cosmological constant moved from "blunder" to a leading explanation for the universe's accelerating expansion.
Theoreticians will have to take the latest findings about dark energy's consistent behavior into account as they try to explain the nature and source of dark energy, Dr. Byrd says.
The team also used these dark-energy measurements to estimate the composition of energy and mass affecting the local group and found that its composition closely approximates estimates for the universe as a whole. For the cosmos, visible matter makes up about 14 percent of all the mass and energy. Dark matter accounts for another 22 percent. And dark energy accounts for 74 percent of the matter-energy density of the universe.
The local group of galaxies is dominated by the gravity from the Milky Way and by its twin, the Andromeda Galaxy, a spiral galaxy some 2.5 million light years from Earth. Many of the other galaxies are satellites of the Milky Way and Andromeda. Others, such as the Triangulum galaxy, aren't.

Determining a galaxy's movement

The group made its discovery by taking precise measurements of the so-called radial velocities of the galaxies in the local group. By studying the light from these galaxies, astronomers can determine if a galaxy is moving toward or away from the Milky Way, and at what rate.
The researchers found that within about 5 million light years from Earth, the vast majority of galaxies were orbiting the group's center of gravity, between the Milky Way and Andromeda. Beyond 5 million light years to the edge of the group, galaxies were moving out from the group. Each galaxy's pace varied depending on its distance from the gravitational center of the group; the farther out they were, the faster they receded.
That pace is consistent with the global pace dark energy is exerting, based on studies of galaxies billions of light year away.

California judge to put landmark gay marriage case on YouTube

A federal judge ruled Wednesday that video of the case challenging California’s Proposition 8 ban on gay marriage can be shown on YouTube. Proceedings are set to start Monday.

San Francisco
The federal case that challenges California’s gay marriage ban will be videotaped and shown on YouTube, a judge ruled Wednesday.

The decision marks a first for a Western district federal court and also highlights the intense interest in this case, which advocates on both sides of the issue say could eventually be heard in the US Supreme Court and amount to a landmark ruling on gay marriage.
“This certainly is a case that has sparked widespread interest,” US District Court Judge Vaughn Walker said of the latest legal challenge to Proposition 8, the voter approved initiative that outlawed same sex marriage in 2008.
Two unmarried same-sex couples are seeking to overturn the ban on grounds that it violates their rights to equal protection under the Constitution. Two high-profile attorneys who argued on opposite sides of the Bush v. Gore case in 2000 – Theodore Olson and David Boies – are representing the couples.

Cameras in the courtroom – in whose favor?

Lawyers arguing in favor of Prop. 8 opposed cameras in the courtroom. They said it could lead to witness harassment and intimidate others from testifying in favor of the gay marriage ban.
But same-sex marriage proponents and members of the media said nationwide interest in the case – and its potential for setting legal precedent – merited cameras in the courtroom.
“This case presents issues that are very important to the public, and will affect millions of people. However, only a tiny fraction will ever be able to watch the trial in person,” wrote the Courage Campaign, a California group that advocates for progressive causes, in a letter to Judge Walker.

A new experiment

The case, which is set to begin Monday, will not be broadcast live. It will instead be shown on a delayed basis via YouTube. A live feed will be shown in satellite courtrooms.
The 9th Circuit Court of Appeals approved the use of video cameras in civil, non-jury hearings on an experimental basis in December.
“We hope that being able to see and hear what transpires in the courtroom will lead to a better public understanding of our judicial processes and enhanced confidence in the rule of law,” said Chief Judge Alex Kozinski. “The experiment is designed to help us find the right balance between the public’s right to access to the courts and the parties’ right to a fair and dignified proceeding.”

A new step forward for robots

Engineers decode human balance to build walking robots.















Jerry Pratt (l.) with research associates push M2V2 to test its balance at the Institute for Human Cognition in Pensacola, Fla.

For the past 30 years, scientists and technicians have grappled with making robots walk on two legs. Humans do it effortlessly, but the simple act has a lot of hidden complexity. And until recently, computers were very bad at it.

Now, several teams across the country are refining the first generation of robots that are close to walking like people. That includes the ability to recover from stumbles, resist shoves, and navigate rough terrain.
In walks PETMAN, designed by Boston Dynamics in Waltham, Mass. The two-legged robot saunters with uncanny realism. The android has no upper body, just steel and plastic legs attached to a system of power cables. But it walks on its own, using the same heel-to-toe motion that humans use. When pushed from the side, PETMAN sidesteps to recover its balance. The robot even wears shoes.
Why make a robot like this? Researchers say walking robots provide them with a benchmark to gauge engineering precision, a chance to improve the lives of older people, and the ability to create more useful machines capable of navigating a world built for humans.
In PETMAN’s case, the Army, which funds the project, needs a machine that can simulate realistic human motions to test dangerous equipment such as chemical protection gear. Boston Dynamics plans to deliver a version with a head and a torso by early 2011.
Marc Raibert, founder and president of Boston Dynamics, says the secrets of balance were almost a complete mystery back in 1980, when he and other robotics experts started the Leg Lab at Carnegie Mellon University in Pittsburgh. In 1986 he moved the Leg Lab to the Massachusetts Institute of Technology in Cambridge, Mass.
With “a lot of the first walking robots, [scientists] tried to make them like a table,” he says. Researchers thought that robots should be permanently stable. These early efforts in robotics attempted to program exactly where each foot should fall, calculate all the possibilities ahead of time – but human and other animals don’t work that way. Instead, we are actually in a kind of controlled fall, using our feet to sense how best to regain balance after each step.
So, the students at the Leg Lab tried different tacks. They created a succession of robots ranging from stiff-legged machines that bounced to droids that looked progressively more natural. Boston Dynamics’ first successes jogged on four legs, such as Big Dog, a military project designed to carry heavy loads across rough terrain. Big Dog can negotiate snow, forests, and rocky hills – terrain that might stymie wheeled vehicles.
Until recently, moving over anything but level ground was out of the question for most robots. Perhaps the most famous walking humanoid robot, ASIMO, was introduced as a prototype by Japanese car company Honda in the early 1990s. Even after years of revisions and learning to run, ASIMO can still be pushed over easily, struggles with uneven terrain, and moves with a bent-knee gait that doesn’t look much like normal walking.
Leg Lab alumni have since fanned out to several different universities and corporations. One of them, Jerry Pratt, is a research scientist at the Institute for Human and Machine Cognition in Pensacola, Fla.

Mr. Pratt says that humans can react to stumbles very quickly – faster than most machines. When you fall or lose your balance, it only takes about 0.43 seconds to respond. Current robots take as much as 0.6 seconds. That’s a lot of time when tumbling.

“It’s really a key requirement when you’re talking about push recovery,” he says. To Pratt, the impressive thing about PETMAN and Big Dog – which he did not work on – is the speed at which they can move their legs in several directions.
On top of that, human legs don’t really flex. They are actually more of a pendulum, swinging relatively freely until you put pressure on them.
At that point, instinct kicks in. Your feet can land anywhere in a wide area without fear of losing balance, because they shift to keep stable. Yet most robots still have feet more reminiscent of a tripod’s stumps than an animal’s paws. Pratt says the key was figuring out how to program the robots so that they readjust after their feet hit the ground.
His robot, M2V2, was started at the Leg Lab. Since then, he has improved the design and can get the machine to stand on one foot, and even shift side to side when elbowed.
M2V2’s nimble feet came from Buckell University, where interim dean of engineering Keith Buffinton and his team designed a foot with pressure sensors. This new development gives M2V2 enough information to judge how to adjust balance. A flat-footed robot can’t do that.
All of this has uses beyond creating humanoid robots. Chris Atkeson, a professor at the Robotics Institute at Carnegie Mellon University, says his goal is to find out why older people tend to fall. If he could properly simulate that in a robot, he could test theories and develop new ways to help. “This is about understanding people,” he explains.
Similarly, in Japan, ASIMO serves a higher purpose than just entertaining during a press conference. Honda spokeswoman Alicia Jones notes that ASIMO’s development helped pave the way for devices designed to assist older people – a big concern in a country with a rapidly aging population.
Mr. Atkeson’s group employs motion-capture technology – similar to what Hollywood uses for realistic computer graphics – to figure out exactly how humans operate. He says there are two things that immediately distinguish humans from current-generation robots.
First is the ability to “damp” motion. If you slap a person’s palm, for instance, the hand will move a little, but only for a second before it goes back into position.
“Humans are well damped,” he says. “We have to find a way to absorb impact energy” in robots.
Second, to have any power, the motors end up moving very slowly because they are in low gear all the time. That’s a big reason it’s hard for them to move as fast as people react.
Another reason to make machines look humanoid is that, for robots to be useful, they have to move through a world designed for people. Houses aren’t built for wheels or creatures wider than they are tall.
Pratt adds that a bipedal robot could even replace humans in risky jobs such as space exploration – where having more legs makes machines a lot more effective on rough terrain.
He notes that when the National Aeronautics and Space Administration sent the Pathfinder probe to Mars, the rover was not able to descend into some craters because it may have never gotten out again.
A legged robot – with either two or four feet – would have had no trouble, Pratt says.

The comparative costs of climate change

How much will mitigating global warming or climate chage cost the world? Here are some comparisons.

A coal-fired plant emits smoke into the air in Shijiazhuang in north China's Hebei province last month. China is concerned about the costs of converting to more environmentally friendly fuels.

How much will decarbonizing the economy cost, and compared to what?

Probably the most widely discussed economic analysis on what the transition to a low-carbon economy will cost is the so-called Stern Review by British economist Nicholas Stern.
First released in 2006, the report put these costs at 1 percent of Gross Domestic Product. Then, in 2008, as it became clear that Earth's climate was changing faster than many had forecast, Stern upped the estimate to 2 percent of world GDP.
While he acknowledges that this cost presents a challenge, he asserts that without this investment the world economy faces a possible climate change-induced recession that would cost 20 percent of world GDP.
As might be predicted, the report was criticized from both sides of the climate-change discussion. Those who favor doing nothing say that Stern sorely underestimates the costs of stopping all fossil fuel use. Those who favor action say that Stern underestimates the potentially catastrophic costs of climate change.
The 2008 Garnaut Report, billed as an Australian version of the Stern Review, supported Stern's basic findings. "[T]he costs of action are less than the costs of inaction," it stated.
And it, too, came under criticism from both sides.
But for our purposes here, let's assume that weaning ourselves off fossil fuels will cost 2 percent of world GDP. How much is that, and what does it mean?
The GDP of the entire world — the Gross World Product — was $61.22 trillion in 2008, according to the CIA World Fact Book.
The largest single GDP, that of the European Union, equalled $18.14 trillion. That's $33,700 per capita.
The United States' GDP, ranked at No. 2 in the world, came in at $14.44 trillion. Per capita, that's $46,900.
So let's break down the costs of climate mitigation:
For the US, 2 percent of GDP equals $288 billion. Per person, that works out to about $938 yearly. It's not exactly nothing. But it's also not overwhelming. On a monthly basis — $78 per month — it's a little higher the price of the average cellphone plan.
How does it compare to our other national expenditures?
The debate over healthcare that's recently occupied the airwaves has underlined just how much the US spends [PDF] on it — some 16 percent of GDP, or $2.26 trillion. By comparison, this preventive measure for our planet's climate — one-eighth the amount — is tiny.
Of course, we have the highest healthcare expenditures per GDP of any country in the world. More to the point, the need for healthcare is often acute. People need it now. By contrast, we'd be decarbonizing the economy for benefits far in the future.

What else compares cost-wise?

According to the National Priorities Project, the combined costs of the wars in Afghanistan and Iraq — initiated as a preventive war — since 2001 is, so far, $950 billion. In 2008 alone, war expenditures surpassed $710 billion. (They've since begun to fall.)
Spending on war equaled 4.8 percent of US GDP in 2008, double what the Stern review says is necessary to address the climate problem.
Other comparisons:

According to this Bureau of Labor Statistics analysis of consumer expenditures in 2008, Americans spend about 5.6 percent ($2,835) of their after-tax income ($50,486) on entertainment. By cutting our consumption of entertainment in half, we could solve the climate problem.
According to the same report, Americans spend $5,605 — 11 percent of their after-tax income – on pension plans and personal insurance. No one is saying that Americans should go without pensions and personal insurance. The point is, we see it necessary to spent a not-inconsiderable portion of our income planning for something that might happen. Indeed, according to this report [PDF], in 2004, Americans spent 6.2 percent of the GDP on non-life-related insurance.
Even if we believe that the vast majority of scientists are lying to us when they tell us that climate change is a problem, shouldn't we at least hedge our bets? That's one take on the argument of economist Martin Weitzman at Harvard University.
"The probability of a disastrous collapse of planetary welfare from too much CO2 is non-negligible, even if this low probability is not objectively knowable," he writes.
In other words, even the probability of something catastrophic happening — the rapid melting of the Greenland ice sheet, for example, or getting in a car accident — is relatively low, if its happening is catastrophic enough, then spending some money to avoid it now is prudent.

Hubble telescope glimpses universe's earliest galaxies

New Hubble telescope images provide a look at the cosmos when it was just 600 to 800 million years old. Galaxies from this period might have helped transform the universe from dark to light.

The recently refurbished Hubble Space Telescope has drawn back a curtain on a group of galaxies that are the earliest the universe has yet produced.
The galaxies, hot, small, and blue, appear as faint patches of fuzz in the image Hubble took of a patch of sky over four days last August, peering back into a period when the cosmos was only 600 million to 800 million years old - less than one-twentieth of its current age - and a little more than 10 percent of its current size.
In addition these early galaxies, the international team of scientists reporting the results Tuesday say their "ultra-deep field" image contains at least three galaxy candidates that existed when the universe was some 500 million years old. They remain candidates because they are too faint for detailed study.
The discoveries help mark a watershed in modern astronomy and cosmology, according to John Grunsfeld, one of the astronauts who helped repair and refurbish Hubble last May and who has just been appointed as deputy director of the Space Telescope Science Institute in Baltimore.
Just a hundred years ago, astronomers such as Edwin Hubble were debating the nature of "nebula" they saw in the night sky – cloudy patches of light that we now know as galaxies. At that time, "we didn't know we lived in a universe where we could see the beginning of star formation and galaxies," Mr. Grunsfeld said at a briefing at the winter meeting of the American Astronomical Society in Washington, D.C.
"This is a remarkable time,” he said, thanks to some remarkable tools that are helping push the frontiers of astronomy.
After the Big Bang
Interest in the universe’s first billion years is running high because it marks a critical phase in the universe’s evolution.
The universe is thought to have begun some 13.7 billion years ago with an energetic burst known as the Big Bang. As the universe expanded and cooled, the building blocks of matter began to distill from the seething soup of higher-energy particles the Big Bang created. The universe cooled to the point where it was populated by run-of-the-mill molecules. Roughly 75 percent of the matter in the universe was hydrogen, 25 percent helium, along with traces of a small handful of other elements. No stars shone. No galaxies pirouetted.
At some point between 100 million and 1 billion years after the Big Bang, cosmologists calculate, the universe slowly began to switch on the lights. The cosmos shifted from the cold and opaque aftermath of the Big Bang to a transparent universe filled with the dazzling display of stars, galaxies, galaxy clusters, and super clusters that humans gaze on today.
"We don't know who pulled the trigger" on this period, known as re-ionization, says Rogier Windhorst, a cosmologist at Arizona State University in Tempe, Ariz., and a member of the Hubble team.

But some of the leading candidates are early galaxies, he says, such as those in the new Hubble ultra-deep field image. They are likely to have been among the early sources of radiation that ionized the molecular hydrogen between galaxies, allowing light to shine throughout the small but expanding universe.

Missing link in galaxy growth

These newly spotted galaxies also represent important "missing links" along the line of galactic evolution, from the first small fragments to the later sprawling spiral and elliptical galaxies tens of thousands of light-years across, including the Milky Way. The team estimates that the earliest galaxies found so far in their survey are only 5 percent of the size of the Milky Way with 1 percent of the Milky Way's mass. At least during the universe's first 2 billion years, galaxies assembled themselves from smaller bits in along a relatively smooth trajectory, the team's data suggest.
"These are the seeds of the great galaxies of today," says Garth Illingworth, a researcher at the University of California at Santa Cruz who led the Hubble observation team.
The stars in the galaxies reported Tuesday show traits that models suggest the universe's first stars would display.
They are "so blue that they must be extremely deficient in heavy elements," notes team member Rychard Bouwens, also at the University of California at Santa Cruz. Those heavy elements, present in varying abundances in today's stars and galaxies, form in the nuclear-fusion furnaces at the heart of every star. Stars shed those elements through their lifespans, and especially at the end of their existence. Succeeding generations of stars sweep up these elements as they form so that on average, later generations become redder and somewhat cooler.
That means the blue stars corralled in the galaxies found in the Hubble survey thus represent a population of stars "that has nearly primordial characteristics," Dr. Bouwens explains.
What the next telescope may discover
Hubble' results leave many astronomers eagerly awaiting the James Webb Space Telescope (JWST), scheduled for launch in 2014. The sizes of the fledgling galaxies in the latest Hubble survey hint at a fairly quick onset of galaxy formation after the Big Bang – a birthing period well within the JWST's detection abilities.
The stars in the tiny galaxy-wannabes are already several hundred million years old, scientists found in combining data from Hubble and the Spitzer Space Telescope.
"JSWT is going to be the telescope that will really reveal these galaxies in their glory and galaxies at earlier times," Dr. Illingworth says.

World's tallest building: What's it worth to have the Dubai tower – and what should people call it?

From the last-minute name change to the engineering feats involved in constructing the world's tallest building, the Burj Khalifa continues to generate a buzz.

Dubai, United Arab Emirates —
The Tower formerly known as Burj Dubai generated more buzz one day after its long-anticipated opening: What’s it worth to have the world’s tallest tower? And what now should the landmark – renamed the Burj Khalifa at the last minute – be called?

“What do we tell taxi drivers now?” one commenter asked on the website, Ahlanlive.
At 2,716 feet, the “superscraper” stands nearly twice as tall as the Empire State Building and reportedly took more than $1 billion and 22 million man-hours to build. It was intended to be the most monumental of megaprojects that have put Dubai on the map in recent years.
Some analysts say the tower’s symbolic value – of confidence, ascendancy, and a pretty remarkable feat of design and construction – is priceless. “You can call it hubris, but we're in awe of the architectural and engineering achievement it represents,” a Los Angeles Times editorial said, calling the Burj a “tower to look up to.”
After all, as the Monitor’s Laurent Belsie noted Monday, the Empire State Building opened during the Depression, the Sears Tower during the mid-1970s downturn, and Malaysia’s Petronas Tower was inaugurated during the 1990s Asian financial crisis. But those skyscrapers withstood the hard times of their early days to become long-lasting icons.
Others put little stock in symbolism. For them, the Burj is there to turn a profit – and is now unlikely to deliver. "If you look at it, it's a really bad idea,” Jim Krane, author of “City of Gold: Dubai and the Dream of Capitalism” told CNN. “It uses as much electricity as an entire city. And every time the toilet is flushed they've got to pump water half a mile into the sky.”
Most buyers purchased properties as investments during Dubai’s real estate boom in 2004, and will now have trouble renting out their luxury apartments in a city already packed with empty, unaffordable high-rises. Real estate prices have dropped by half from their peak in 2008 and have farther to fall.
The unexpected name change has created additional losses. Souvenir vendors will have to throw away their mass-produced T-shirts bearing the old name; security officials will need new uniforms with new logos; and the government will have to replace the many road signs already pointing the way to the Burj Dubai, a blogger at the Chicago Tribune pointed out.
Still, the tower continues to invite speculative investment. Some enterprising Internet users lost no time wondering what to make of the new name and instead acted fast to buy the domain name www.burjkhalifa.com.
The website is still under construction as its owners now wait, presumably, to be bought out at a much higher price.

Twilight

Twilight is a 2008 romantic-fantasy film. It is the first film in The Twilight Saga film series, directed by Catherine Hardwicke and based on the novel of the same name by Stephenie Meyer. It focuses on the development of a personal relationship between human teenager Bella Swan (Kristen Stewart) and vampire Edward Cullen (Robert Pattinson), and the subsequent efforts of Cullen and his family to keep Swan safe from a separate group of hostile vampires.
The project was in development for approximately three years at Paramount Pictures, during which time a screen adaptation which differed significantly from the novel was written. Summit Entertainment acquired the rights to the novel after three years of the project's stagnant development. Melissa Rosenberg wrote a new adaptation of the novel shortly before the 2007–2008 Writers Guild of America strike and sought to be faithful to the novel's storyline. Principal photography took 44 days,and completed on May 2, 2008. The film was primarily shot in Washington and Oregon in early 2008.
Twilight was released in theaters on November 21, 2008, and grossed US$35.7 million on its opening day. The film has grossed US$384,997,808 in worldwide box office and, as of January 2010, $178,166,045 in North American DVD sales. The soundtrack was released on November 4, 2008. New Moon and Eclipse, the next two books in the series, were produced as films the following year.

Plot

Seventeen-year-old Isabella "Bella" Swan moves to Forks, a small town near Washington state's rugged coast, to live with her father, Charlie, after her mother remarries to a minor league baseball player. She is quickly befriended by many students at her new high school, but she is intrigued by the mysterious and aloof Cullen siblings. Bella sits next to Edward Cullen in biology class on her first day of school; he appears to be disgusted by her, much to Bella's confusion. A few days later, Bella is nearly struck by a van in the school parking lot. Edward inexplicably moves from some feet away and stops the vehicle with his hand. He later refuses to explain this act to Bella and warns her against befriending him.
After much research, Bella eventually discovers that Edward is a vampire, though he only consumes animal blood. The pair fall in love and Edward introduces Bella to his vampire family, Carlisle, Esme, Alice, Jasper, Emmett, and Rosalie. Soon after, three nomadic vampires—James, Victoria, and Laurent—arrive. James, a tracker vampire, is intrigued by Edward's protectiveness over a human and wants to hunt Bella for sport. Edward and his family risk their lives to protect her, but James tracks Bella to Phoenix where she is hiding and lures her into a trap by claiming he is holding her mother hostage. James attacks Bella and bites her wrist, but Edward, along with the other Cullen family members, arrives before he can kill her. James is destroyed, and Edward sucks James's venom from Bella's wrist, preventing her from becoming a vampire. A severely injured Bella is taken to a hospital. Upon returning to Forks, Bella and Edward attend their school prom. While there, Bella expresses her desire to become a vampire, which Edward refuses. The film ends with Victoria secretly watching the pair dancing, plotting revenge for her lover James' murder.

Comparison to the book

The filmmakers behind Twilight worked to create a film that was as faithful to the book as they thought possible when converting the story to another medium, with producer Greg Mooradian saying, "It's very important to distinguish that we're making a separate piece of art that obviously is going to remain very, very faithful to the book.... But at the same time, we have a separate responsibility to make the best movie you can make." In order to ensure a faithful adaptation, author Stephenie Meyer was kept very involved in the production process, having been invited to visit the set during filming and even asked to give notes on the script and on a rough cut of the film. Of this process, Meyer said, "It was a really pleasant exchange [between me and the filmmakers] from the beginning, which I think is not very typical. They were really interested in my ideas," and, "...they kept me in the loop and with the script, they let me see it and said, 'What are your thoughts?'... They let me have input on it and I think they took 90 percent of what I said and just incorporated it right in to the script."Meyer fought for one line in particular, one of the most well-known from the book about "the lion and the lamb", to be kept verbatim in the movie: "I actually think the way Melissa [Rosenberg] wrote it sounded better for the movie...but the problem is that line is actually tattooed on peoples' bodies... But I said, 'You know, if you take that one and change it, that's a potential backlash situation.'" Meyer was even invited to create a written list of things that could not be changed for the film, such as giving the vampires fangs or killing characters who don't die in the book, that the studio agreed to follow.The consensus among critics is that the filmmakers succeeded in making a film that is very faithful to its source material,with one reviewer stating that, with a few exceptions, "Twilight the movie is unerringly faithful to the source without being hamstrung by it."
They could have filmed [the script developed when the project was at Paramount] and not called it Twilight because it had nothing to do with the book... When Summit [Entertainment] came into the picture, they were so open to letting us make rules for them, like "Okay, Bella cannot be a track star. Bella cannot have a gun or night vision goggles. And, no jet skis...."
—Twilight author Stephenie Meyer
However, as is most often the case with book-to-film adaptations, differences exist between the movie and original source material. Certain scenes from the book were cut from the film, such as a biology room scene where Bella's class does blood typing. Hardwicke explains, "Well [the book is] almost 500 pages — you do have to do the sweetened condensed milk version of that.... We already have two scenes in biology: the first time they're in there and then the second time when they connect. For a film, when you condense, you don't want to keep going back to the same setting over and over. So that's not in there." The settings of certain conversations in the book were also changed to make the scenes more "visually dynamic" on-screen, such as Bella revealing that she knows Edward is a vampire in a meadow in the film, as opposed to in Edward's car in the novel. A biology field trip scene is added to the movie, in order to condense the moments of Bella's frustration at trying to explain how Edward saved her from being crushed by a van. One of the largest changes was the introduction of the villainous vampires much earlier in the film than they appear in the book, with Rosenberg explaining that, "you don't really see James and the other villains until to the last quarter of the book, which really won't work for a movie. You need that ominous tension right off the bat. We needed to see them and that impending danger from the start. And so I had to create back story for them, what they were up to, to flesh them out a bit as characters." Rosenberg also combined some of the human high school students, with Lauren Mallory and Jessica Stanley becoming the character of Jessica in the movie, and a "compilation of a couple of different human characters" becoming Eric Yorkie. About these variances from the book, Mooradian stated, "I think we did a really judicious job of distilling [the book]. Our greatest critic, Stephenie Meyer, loves the screenplay, and that tells me that we made all the right choices in terms of what to keep and what to lose. Invariably, you're going to lose bits and pieces that certain members of the audience are going to desperately want to see, but there's just a reality that we're not making 'Twilight: The Book' the movie."