blackhole

Slide 1:

What are Black Holes Anyway? Black holes are not really holes at all. They are the opposite of empty. Very interesting! A hole that is not a hole.

Slide 2:

Black holes have the most matter stuffed into the least space of any objects in the universe. It’s like taking everything on Earth and squishing it into a teaspoon.

Slide 3:

Because they are so compact, they have very strong gravity. It’s like a giant vacuum sucking everything in.

Slide 4:

Here on Earth, gravity is what makes things fall down, rather than just float away, when you let go of them. Gravity is what you are measuring when you step on a scale to weigh yourself.

Slide 5:

Your weight is the amount of force that Earth’s gravity exerts on you. The more matter your body contains, the more you weigh. Likewise, the more matter an object has, the stronger its gravity. Gravity More Gravity

Slide 6:

The gravity of a black hole is so strong that not even light can escape. Even if a bright star is shining right next to a black hole, you cannot see the black hole.

Slide 7:

Instead of reflecting the light as other objects do, the black hole just swallows the starlight forever. Any matter that gets too close to a black hole gets swallowed up as well. Black holes swallow everything in their paths.

Slide 8:

One kind of a black hole is called a stellar-mass black hole. You can think of it as a "one-big-star" black hole. This type of black hole forms when a big star burns up all its fuel and explodes (called a supernova). Then what’s left collapses into a super-compact object—a black hole.

Slide 9:

Stars must contain quite a bit more matter than our Sun for this to happen. So our Sun, and most stars, will never become black holes. I will never be large enough to be a black hole.

Slide 10:

Stellar-mass black holes are only a few tens of kilometers across—maybe about 40 miles. Just imagine. Our Sun is so huge that about one million Earths would fit inside it. A star with enough matter to become a black hole contains maybe 10 times as much matter as the Sun. So, even though a black hole appears smaller it is much heavier.

Slide 11:

Now imagine a star with that much matter, shrinking into a space no farther across than the distance you can drive a car in less than one hour! The mass of 10 stars fits in 40 miles.

Slide 12:

A black hole with all the mass of Earth would be about the size of a fingernail! Squish all of Earth into a space the size of a fingernail and that would be similar to the density of a black hole.

Slide 13:

Another kind of black hole is called a super massive black hole . You can think of this type as a "million-big-star" black hole, because it contains as much matter as one million to 100 million Suns! A million suns fit in a super massive black hole. Holy Cow!

Slide 14:

Astronomers think that super massive black holes are lurking at the centers of galaxies, including our own Milky Way galaxy. They don't know yet how these humongous black holes are formed. Black hole in the c enter of our galaxy.

Slide 15:

Scientists really want to learn more about black holes and other strange and massive objects in the Universe . Two space missions are helping them do just that.

Slide 16:

One is a space telescope called XMM-Newton. It was launched into Earth orbit in 1999 by NASA and the European Space Agency. It observes the universe in high-energy x-rays, a type of light that we can’t see with our eyes. Artist's idea of XMM Newton Space Telescope. Image courtesy of D. Ducros and the European Space Agency (ESA).

Slide 17:

Matter, such as gas and dust particles, near black holes puts out x-rays as it swirls around at light speed just before the black hole swallows it up. By observing these x-rays, XMM can help scientists understand the black hole.

Slide 18:

Another mission that will study black holes is LISA, which stands for Laser Interferometer Space Antenna. (Thank goodness for abbreviations!) NASA plans to launch LISA in 2015. LISA’s three spacecraft will form a triangle 5 million kilometers (that’s about 3 million miles) on each side.

Slide 19:

This spacecraft triangle will orbit the Sun just like Earth does, but the LISA spacecraft will tag far behind Earth in its journey around the Sun. LISA’s three spacecraft will be “connected” by laser beams to make a giant virtual antenna.

Slide 20:

What will LISA be looking for? These are ripples in space-time itself that occur when massive objects such as black holes move through space. No one has ever detected a gravitational wave before, but scientists are almost 100% certain they exist. But gravitational waves are very weak.

Slide 21:

LISA will have to be extremely sensitive and have very advanced technology to detect them. LISA will help scientists, and the rest of us, understand black holes and other massive objects in the Universe.