美国有线新闻 CNN 朱诺号探测器进一步解密木星 美国即将进入夏令时（在线收听）

AZUZ: Compared to earth's mass, Jupiter is thought to be much larger than that. And scientists say NASA's Juno spacecraft has led to new findings about Jupiter.

For one thing, they believe the planet's surface has bands of gas and winds that flow very quickly in opposite directions. They don't know how deeply these bands extend, though, but information from Juno has led them to conclude that Jupiter's outer layer extends 1,900 miles beneath the surface of the planet.

So, how did they come up with this? Juno took measurements of Jupiter's gravitational field, which scientists use to more deeply analyze the planet. They also concluded that though Jupiter's interior is thought to be fluid, it rotates like a solid body.

The Juno mission cost the U.S. a little over $1.1 billion. It's hoped to help scientist better understand the solar system's largest planet.

Jupiter is located fifth in line from the sun. Both Jupiter and the Juno's spacecraft were named after characters in Roman mythology.

Back down to earth now, the United States is gearing up for a time change that said to give Americans more light in the evening. Actually, the light itself won't change but the time on the clock when it's still light outside well.

Daylight Savings Time begins when clocks are moved forward one hour. The exact technical time when this is supposed to happen is at 2:00 on Sunday morning when it will instantly become 3:00. It could mean one fewer hour of sleep unless we go to bed early, and it could make us late for everything on Sunday if our clocks aren't set.

There are historic reasons for springing forward.

JENNIFER GRAY, AMS METEOROLOGIST: So why do we change the clocks ahead one hour in the spring and back one hour in the fall?

Well, it's actually to reduce the electricity consumption by extending the daylight hours.

SUBTITLE: Why do we change our clocks?

GRAY: In the U.S., we change our clocks at 2:00 a.m. on the second Sunday in March. That begins Daylight Saving Time, that's when we spring ahead.

On the first Sunday in November, we change our clock at 2:00 a.m. again, that's actually just going back to Standard Time.

Believe it or not, this started with an idea from Benjamin Franklin. Franklin did write an essay suggesting that people could use less candles if they got up early and made better use of daylight.

In 1918, the Standard Time Act established time zones, and Daylight Saving Time. But not all states participate. To this day, most of Arizona and all of Hawaii do not change their clocks.

Over 70 countries across the world observe Daylight Saving Time, with notable exceptions of China and Japan.

In 2007, we actually change the date of when we set our clocks back an hour to the first week in November. This helped protect trick-or-treaters by giving them an extra hour of daylight.

One of the other lines of thinking was that we would have a better voter turnout on election years.

Experts say each time you change your clocks, it's always a good idea to change those batteries in your smoke detector and always look forward to fall when you get that extra hour of sleep.