That is our lead story today.

Hello, everyone, welcome to CNN STUDENT NEWS. My name is Carl Azuz.

Back in April, two bombs went off near the finish line of the Boston marathon.

Three people were killed, at least 264 others were injured.

The suspects are brothers, Tamerlan and Dzhokhar Tsarnaev.

They are also accused of killing a campus police officer in the days following the bombing.

Tamerlan was killed in the shootout with police.

Dzhokhar was arrested and charged with multiple crimes,

but yesterday`s court hearing was for two other people.

Dias Kadyrbayev, in the middle of this photo, and Azamat Tazhayakov to his left.

They are friends of Dzhokhar Tsarnaev.

They have been charged with obstructing justice and conspiracy to obstruct justice.

They weren`t involved in the actual bombing.

Authorities say they took items from Tsarnaev`s dorm room after the bombing, in order to hide them from investigators.

Yesterday`s hearing was an arraignment, when defendants are called to court to respond to the charges against them.

It only lasted four minutes.

The two defendants heard the charges against them, entered pleas of not guilty, and were led back out of the court.

Some survivors of a Florida sinkhole are saying a security guard saved lives.

It`s part of a resort near Disneyworld, crumbled into the ground Sunday night.

This is how Richard Shanley reacted.

RICHARD SHANLEY, SECURITY GUARD: I went door to door, just beating on the doors, trying to get people out, and making sure they were safe.

I went floor to floor, got everybody out, and at the time I got done, I really didn`t think about it.

I just got them out and then got out myself.

AZUZ: Everyone in the building made it out safely, no injuries, but that`s not always how things work out with sinkholes.

Here`s CNN`s John Berman.

JOHN BERMAN, CNN CORRESPONDENT: That`s what a sinkhole sounds like, swallowing the summer bay resort early Monday morning.

The 60-foot wide crater in Claremont, Florida, just the latest incident in this year`s string of sinkholes across the country.

In July, 60-year-old Pamela Knox plummeted into a nearly 20-foot sinkhole, while driving on a busy Toledo, Ohio street.

But some have not been so lucky.

In February, a sinkhole opened up underneath a suburban Tampa home,

killing 36-year-old Jeff Bush, who was sleeping in his bedroom.

This is how sinkholes are formed.

A cavity slowly develops in the limestone bedrock.

Over time, it widens, eventually breaking the surface.

Then, the clay and sand above collapse into the hole, swallowing everything in its path.

Repairs can be costly.

UNIDENTIFIED FEMALE: See if you can ID me.

I`m part of the U.S. government whose members serve lifetime terms.

I`ve had 112 total members.

Right now I have nine.

Some of my famous alumni include Thurgood Marshall, Sandra Day O`Connor, and William Taft.

I`m the U.S. Supreme Court, the top of the U.S. judicial branch of government.

AZUZ: The U.S. Supreme Court is responsible for interpreting laws.

The nine justices, one chief and eight associate justices, rule on whether or not laws and government actions violate the U.S. Constitution.

The decision that the Supreme Court justices make can have a direct impact on our lives.

Today we are checking out some of the court`s rulings from its most recent session.

It`s a part of our week-long look back at summer news stories.

AZUZ: The U.S. Supreme Court starts its annual session in October,

but some of the court`s decisions don`t come out until late June or July,

after most of you started your summer break.

So here is a quick recap of some of the bigger rulings from the most recent Supreme Court session.

First up, a case that focused on whether colleges and universities can take a prospective student`s race into account when making admission decisions.

The majority of Supreme Court justices ruled that schools can use race in the admissions process,

but only in limited ways that must stand up against a close legal review.

The justices said those standards were not applied correctly by lower courts in this particular case.

So it was sent back to a lower court for further review.

Next, a case about the 1965 Voting Rights Act.

It was designed to give African-Americans equal voting access.

Part of the law said certain states and counties had to get the federal government`s approval

before making any changes to voting laws or regulations.

Five of the Supreme Court justices declared that rule is unconstitutional.

Congress must now revise the law, but states and counties can change their laws without getting the U.S. government`s permission.

And finally, two Supreme Court cases on the issue of same-sex marriage.

Both of these decisions were 5-4 rulings.

In the first case, the majority of justices found that same-sex couples who were married legally

had the same right to the same federal benefits as heterosexual couples.

The other case had to do with same-sex marriage in California.

It was legal there until a ban, called Proposition 8, was passed by voters.

A lawsuit let a lower court to declare Proposition 8 unconstitutional.

The U.S. Supreme Court ruling upheld that decision,

clearing the way for gay and lesbian couples to start getting married again in California.

The Supreme Court`s ruling only applies to California.

The court did not offer a decision about same-sex marriage that would apply to all 50 states.

AZUZ: You`ve seen some of the new stuff we have in our show this year.

Teachers, this applies to our website too.

When you go to cnnstudentnews.com, click on the box that says, "teaching tools."

Every day, that`s where you`ll find the transcript of our program, our enhanced daily curriculum with the media literacy question of the day.

We`ve got a printable version of the curriculum too.

Plus, our downloadable maps and a place for new teachers to comment on the day`s show.

It`s a one-stop shop for all the great free resources you expect from us.

Check it out. CNNstudentnews.com.

UNIDENTIFIED FEMALE: It`s time for the shoutout.

About how fast is the speed of sound?

If you think you know it, then shout it out.

Is it around 250, 580, 760 or 1,500 miles per hour?

You`ve got three seconds, go.

At sea level, the speed of sound is about 760 miles per hour.

That is your answer and that`s your shoutout.

AZUZ: There are vehicles, like some fighter jets, that travel faster than the speed of sound.

But most folks, you and I, don`t have access to them.

A billionaire who is involved in private space travel and electric cars wants to change that.

These are designs for something called the Hyperloop.

Elon Musk, a billionaire, says it can get from San Francisco to Los Angeles in 30 minutes.

It would move at around the speed of sound, using electric motors and air pressure to zip back and forth through a tube.

Musk admits there are challenges, but the idea has people talking.

ELON MUSK, BILLIONAIRE: It`s a cross between a Concord, a rail gun, and an air hockey table.

UNIDENTIFIED FEMALE: It sounds like something out of the cartoon show, "The Jetsons."

A space age method of transport that some say can get you from New York to LA in less than an hour.

UNIDENTIFIED MALE: Sort of like an enclosed tube, and we just blast air through that,

kind of like, you know, those old-school mail systems where they stuff the package up and it gets sucked up,

and it`s going to be launched out of this rail gun, boom, you`re off. 600 miles per hour.

UNIDENTIFIED MALE: He`s either a visionary, or he`s barking mad, what he`s come up with.

But the core of this is a tube that would be on pillars from Los Angeles to San Francisco,

and inside there would be capsule cars that would be rocketed forward.

Elon Musk basically says that this is the way of the future.

UNIDENTIFIED MALE: It is a voice that is needed to move us forward.

Somebody that says, you know, these old ways aren`t working.

Old transit is kind of boring, it`s inefficient. Why don`t we leapfrog all that with something radical.

UNIDENTIFIED FEMALE: If billionaire entrepreneur Elon Musk has his way, you will be able to do this in another 7 to 10 years.

UNIDENTIFIED MALE: I don`t think we`re going to be seeing this really any time soon.

I think there are other technologies that could dramatically change the way we travel that are going to be available far sooner than anything like this.

Autonomous vehicles, commonly called self- driving cars, or driverless cars.

You have a number of companies such as Google, Volkswagen and Bosch (ph).

UNIDENTIFIED FEMALE: But in the real world, there will be challenges.

UNIDENTIFIED MALE: We`re going to have some serious not in my backyard problems.

UNIDENTIFIED FEMALE: To reduce the resistance and the friction, the air would be pumped from the front to the bottom of the capsule,

which would essentially cause it to float on compressed air, so just think of an air hockey table, and that is the kind of effect that you get there.

UNIDENTIFIED FEMALE: So I am imagining my face, I go, ooh, is this going to be something I want to ride on?

UNIDENTIFIED MALE: I think so. Because in a controlled environment, speed itself does not actually impact human health.

AZUZ: Well, the Hyperloop might sound as unbelievable as a car that drives across the water.

There it is. Amazing amphibious automobiles.

They certainly made some waves as they came floating down the Chicago River last week.

Look like cars, but move like jetskis.

That`s because they are jetskis. They just have a car`s body on top.

The fakeout might deserve some chassis-tisement (ph), but it was all a marketing stunt anyway, so don`t let it drive you nuts.

After all, it was a wheelie (ph) clever scheme.

Time for us to take a break. We`ll be back tomorrow. For CNN STUDENT NEWS, I am Carl Azuz.

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