Most maps show places you can visit and how to get there．Most maps, however, were not made by astronomers．At a recent meeting in Texas, three teams of these scientists presented new maps to show where dark matter was．

Dark matter neither produces nor reflects light, which means it's invisible (看不见) to human eyes and to most scientific instruments．That makes it a challenge to measure and study．What makes the matter more upset: Scientific measurements show that the universe holds about five times．as much dark matter as ordinary matter．Making up the known part of the universe, ordinary matter includes you, your dog, Earth, the sun, stars and planets．

Scientists find dark matter in the same way, they discover other things we can't see-by observing how the invisible matter affects things we can see．We can't see wind, for example, but we can feel a gentle wind or watch a windmill(风车) turning on a hill．Dark matter doesn't turn windmills, but it does have gravity．Like ordinary matter, dark matter holds everything around it firmly with gravity．Dark matter's gravity holds galaxies (星系) together and bends rays of light as they move past．

To make the new maps, astronomers trained powerful telescopes to watch for bending light arriving from distant galaxies．These telescopes recorded light that came from galaxies billions of light-years away．By studying how the light changed as it traveled through space, the astronomers could work out the location and shape of dark matter groups．

One of the new maps shows dark matter is more than 600 times as large as a full moon．The other covers an area more than a thousand times as large．But that's just the beginning: The astronomers want to carry on further studies to better understand the dark matter．

The United States Postal Service(LISPS)is offering a way to people who are interested in seeing tomorrow’s mail today．The postal service will send consumers images(图像)of their letters，magazines and other mail before they arrive．The new service is called Informed Delivery．It is an attempt to remain competitive in an ever—changing world．

Postal service officials say the increased use of email，digital messaging services and social media has made it difficult to stay relevant．David Rupert is a media relations specialist who spoke about the competition the agency now faces．Whether you turn on a television or your computer，or people come to your door with different products and services，all of those are competing for consumers’time and energy，he said．

Interested users are first required to sign up for Informed Delivery．Once registered，the consumer receives a daily email with virtual(虚拟)images of letters or other things to be delivered．The US Postal Service says it can especially help those who have a mailbox at their local post office，so they know when to get their mail：

Another postal offering is a service that seeks to make advertising-related mail-often called junk mail—more fun．The service uses virtual and augmented reality(虚拟现实和增强现实)to let consumers interact with their junk mail．Many companies put special coding on their advertising，which can give users an interactive experience．Some companies even put virtual reality eyeglasses in the mail to make their ads come to life．Consumers have mixed reactions to virtual and augmented reality advertising．“You can find some good things within junk mail．It is a good idea．We’11 see how it works，”Postal service user Victor Teah said．But Jocelyn Coatney doesn’t think it would change her mind about junk mail．“For some，that might be fun．But for me，it would be useless，”she said．

There are lots of ways to educate yourself on the Internet. You can find photos, documents, and films on almost any topic you can imagine. And at www.ted.com, you can access lectures by artists, scholars, designers, technicians and others.

TED began in 1984 as a conference that brought together individuals from the fields of technology, entertainment and design. It was intended to be a one-time event focusing on technology and design. The event ended up losing money, and it was six years before the founders tried it again. This time it worked, and since 1990, the TED conference has been an annual event. There are now two held every year, with topics as diverse as music, medicine, and money. Other specialized spin-off conferences address narrower issues.

The TED website came from a desire to share the conferences with the world, to “offer free knowledge from the world’s most inspired thinkers,” as the website puts it. The current version of the site was launched in April 2007, and contains videos of talks given at the TED conferences around the world. The talks are transcribed into hundreds of languages.

The TED website is owned by the Sapling Foundation, a non profit devoted to fostering the spread of great ideas. The Sapling foundation acquired TED in 2001. Since then, it has been focusing on using TED to broadcast ideas that might change the world.

TED, of course, isn’t immune to criticism. It’s been called elitist(精英) for its high ticket prices (more than 6,000 dollars total). It’s been accused by a few people of censorship for not publishing their talks. One controversial speaker was upset about being criticized by the conference’s host afterward.

The complaints, however, seem to be relatively few for such a large, long-running organization. And accusations of elitism ring hollow when so much is given away for free on TED’s website. Whatever its failings, TED is a source of inspirational information for those who seek it out.