The Men in Black are back! How does cutting-edge science stack up against the fictional world of Men in Black 3?

[ILLUSTRATION OMITTED]

Could extraterrestrials be roaming the streets of New York City? Yes, according to the movie Men in Black 3, which lands in theaters this month.

In this installment of the film series, Will Smith's Agent J will battle evil aliens and travel back in time to rescue his partner, Agent K, played by both Tommy Lee Jones and Josh Brolin--all while keeping a lid on the secret that aliens are living undercover here on Earth.

But how close are we to meeting aliens, traveling back in time, or wiping people's memories? Find out how these science-fiction staples stack up against scientific fact.

ALIENS UNDER WRAPS

In the films, Men in Black is a secret organization charged with keeping the presence of aliens on Earth a secret. Some of these extraterrestrials look just like us, some weal" special disguises that conceal extra arms or legs, and other, more-conspicuous aliens hole up in secret hideouts.

Although some people believe that aliens really do walk among us, it's not likely, says Seth Shostak, an astronomer at the SETI Institute in Mountain View, California. SETI stands for Search for Extraterrestrial Intelligence. SETI researchers use radio telescopes to scan the skies for evidence of technologically advanced alien civilizations. "What you do is point your telescopes at stars that might have planets, and hope to pick up aliens' television, radio, or radar signals," says Shostak.

Many astronomical objects emit radio waves, including planets, stars, and black holes. But these signals are chaotic, much like the static you hear when scanning stations on a car radio. Discovering a signal from intelligent life would be like finding a signal at a spot on your radio dial that plays music. "Such signals would tell you that you'd found some sort of life that can build a powerful radio transmitter, so they must be pretty advanced," says Shostak.

So far, SETI hasn't located intelligent life out there. Astronomers have been hunting for a clear signal since the 1960s and will keep scanning the skies in the hope that one day they'll make contact.

MODIFYING MEMORIES

Unwitting civilians often stumble upon Agents J and K as the two tackle rogue aliens on the streets of Manhattan. To keep these events secret, the agents use a device--found only in Hollywood--called a neuralyzer. A flash of light from this marker-shaped memory wiper allows the agents to rewrite witnesses' memories of the aliens they've seen.

Memories are stored in a web of connections between brain cells, or neurons. Neurons communicate with each other using electrical impulses and chemicals. A team of neurologists at SUNY Downstate Medical Center in New York has been working to figure out if memories can be erased.

[ILLUSTRATION OMITTED]

The researchers found that a special form of a protein called PKMzeta is responsible for the formation and storage of memories (see diagram, below). When the team injected rats' brains with a drug that blocks PKMzeta, the rats forgot everything--their fears, their favorite foods, and the location of their favorite hideouts.

Someday, a more finely tuned method of using PKMzeta could erase painful memories or treat diseases like post-traumatic stress disorder, chronic pain, and drug addiction. "It will be a lot like Men in Black--but not with a flash of light. It'll be more like a drug," says Todd Sacktor, the research team's lead neurologist.

[ILLUSTRATION OMITTED]

BACK IN TIME

About 20 minutes into the movie, Will Smith wakes up to find that his partner, Agent K, died back in 1969 because an evil alien tampered with time. Agent J must now return to 1969 to save his partner. "Otherwise, not only will present-day Agent K never exist, but the world will be destroyed because Agent K did something in 1969 that saved Earth," says the film's director, Barry Sonnenfeld.

Time is a dimension like length, width, and height. "The difference between time and these other dimensions is that right now we can only go forward in time," says Charles Liu, an astrophysicist at the College of Staten Island in New York. With our current understanding, there's no way to travel back in time without violating the laws of physics.

However, one place where time travel might be possible is at the center of a black hole. No one knows what goes on deep inside these collapsed stars, which have so much gravity that even light can't escape their pull.

"There is no way to communicate with the interior of a black hole--using radio signals or smoke signals or sign language or anything else," says Liu. There's a chance that if you were to travel to the center of a black hole--and if you were to make it out alive--you might pop out in another time.

String theory might also offer an explanation for how Smith travels back to 1969 in Men in Black 3. String theory says that tiny vibrating structures called strings are the smallest things in the universe. These strings are the building blocks of the building blocks of atoms. Strings extend beyond the four dimensions of space and time in our universe. String theory allows for the mathematical possibility of an infinite number of parallel universes existing simultaneously.

A form of time travel might be possible by combining string theory's parallel universes with the many worlds hypothesis, which spawns alternative timelines based on the choices that everyone makes. For example, today you wore jeans to school, but you chose the jeans over khaki pants. According to the many worlds hypothesis, there's another world with another version of you that wore khakis today. Every time you make a decision, there's another world that exists based on the possibility that you made the other choice. According to this method, you wouldn't exactly be time-traveling. It's more like you would be jumping between universes.

"We don't have the technology or overall knowledge of the universe yet to really work it out, or a way to find out whether these theories are true or false," says Liu. But it gives you something to think about as you watch Agent J travel back in time to 1969 to save Agent K--and hopefully the world!

COULD MEMORIES BE ERASED?

After an event occurs, it is stored in your short-term memory for about an hour before being committed to your long-term memory. "If you recall a memory, it goes back into short-term and then gets converted again into the long-term in a process called reconsolidation," says neurologist Todd Sacktor. Sacktor and his team are wiping rats' memories by combining reconsolidation with a drug that blocks PKMzeta. Here's how it could work in humans.

[ILLUSTRATION OMITTED]

[1] MAKE A BAD MEMORY

Long-term memories are very stable once they're made. A protein called PKMzeta ensures that the memory remains stored in the neurons.

[ILLUSTRATION OMITTED]

[2] REMEMBER THE EVENT

The act of remembering causes PKMzeta to break down and transfers the memory back to the short-term memory.

[ILLUSTRATION OMITTED]

[3] DESTROY THE MEMORY

Doctors administer a drug that blocks the formation of PKMzeta after a patient recalls a bad memory. Without PKMzeta, the memory will not be reconsolidated back into the long-term memory.

[ILLUSTRATION OMITTED]

[4] THE BRAIN GETS BACK TO WORK

Only the bad memory is deleted. Everything else in the brain is unchanged.

WHAT DO YOU THINK?

Do you think someday we'll be able to travel back in time? What time period would you travel to?

STANDARDS

NATIONAL SCIENCE EDUCATION STANDARDS: Grades 5-8: Understandings about science and technology Grades 9-12: Understandings about science and technology

COMMON CORE STATE STANDARD: WRITING STANDARD: 3. Write narratives to develop imagined experiences or events.

OBJECTIVE

Students will learn how the science fiction in a new movie compares with real-life science facts.

BEFORE READING

* What is science fiction? (a genre of fiction based on imagines future, scientific, or technological advances and major social or environmental changes, frequently portraying space or time travel and life on other planets)

* How do you think science fiction writers come up with their story ideas?

* Do you think that, intelligent alien life exists somewhere in the universe? Why or why not?

LESSON

1. Have students look at the cover of the magazine. Do they recognize the actor pictured? (Will Smith) Ask the beforereading questions above. Then go to www.scholastic.com /scienceworld. Open the digital edition to page 8, and have students do the same in their magazines. Call on a volunteer to read the headline and the text just beside it.

2. Ask students if they have seen any of the older Men in Black movies. What science fiction elements from the movies do they remember? How are these elements different from real life'?

3. Read the article as a class. Stop at the end of the section "Aliens Under Wraps." Use the highlighter tool to highlight the science fiction element that is discussed in this section. Then ask students to compare the movie elements with the science facts described in the article. Record their answers on a digital sticky note.

4. Continue reading the article, stopping at the end of each section to summarize how the science fiction concept compares with reality. Discuss how different the fictional world is from the real one. Do students think that one day, the two worlds will be more similar? How?

DISCUSSION

Read the text in the box labeled "What Do You Think?" on page 11. "Do you think that. someday we'll be able to travel back in time? What time period would you travel to?" Many science fiction movies use time travel in their plots. Why do you think science fiction writers find this idea so interesting?

ASSESSMENT

[ILLUSTRATION OMITTED]

Learn how scientists are searching for planets outside our solar system with the "Out of This World" work sheet found under the orange "Skills Sheets" button at www.scholastic.com/scienceworld.

DON'T TEACH EARTH SCIENCE?

Go to www.scholastic.com/scienceworld and click on the orange Skills Sheets button to download these assessments:

BIOLOGY: HUNTING FOR ALIENS

[ILLUSTRATION OMITTED]

The kind of intelligent alien life you see in the movies may be worlds away or only a fantasy. But scientists believe there may be simpler forms of alien life much closer to home. Read this passage to learn about the search for life on Mars.

COMMON CORE: BE A SCIENCE FICTION WRITER!

[ILLUSTRATION OMITTED]

Let science ignite your students' imaginations! Use this work sheet to guide students in writing a short science fiction story that is inspired by real science facts.

* VIDEO EXTRA: Watch this video about time travel: www, scholastic.com/scienceworld.

* Download activities and other curriculum tools about the search for life in the universe at SETI's educational Web site: www.seti.org/epo/litu.

* Can we really travel back in time? Use this lesson plan and short video to learn how Einstein's theory of relativity relates to time travel: www.teachersdomain.org/resource/nvfc.sci.physics.time.