Page 57 - Curriculum Visions Dynamic Book

Planet discoveries
Recent sweeps of the domelike bulge of the Milky Way by the Hubble Space Telescope have discovered large numbers of new planets orbiting stars in our galaxy. As a result, in 2004 the number of planets orbiting stars in our galaxy has risen to 230 and is certain to increase. The discovery lends support
to the idea that almost every sunlike star in our galaxy, and probably the Universe, is accompanied by planets.
 Our star has planets surrounding it. It is likely that this is a commonplace feature of the Universe. But planets are so small that they have never been seen before outside our galaxy. This picture shows a newborn star
with a long band of gas (nebula) pointing toward a faint companion object (bottom left), which could be the first planet from another star system to be imaged directly. It may be a hot, young protoplanet several times the mass of Jupiter, orbiting at a distance of 210 billion kilometres from the star.
How the Universe might continue
It is no easier to predict what might happen in the future than to wonder how it all began. We know that the Universe is expanding, but it may or may not go on expanding forever. That depends on the mass of material in the Universe, an amount that is still a matter of speculation. Some think the Universe will continue to expand forever. Others believe that the Universe will continue to expand for a while, then begin to collapse back to the point it came from.
It is likely that our views will change as we learn more about the Universe. For example, we are only just finding examples of planets in other star systems. What else might there be to find?
Central to all of the wonder about the Universe is whether space and time can have a beginning and an end (that is, they are finite), or whether there is no beginning and no end (that is, they are infinite). Will everything end when matter comes back together? Will there be a Big Crunch? We still do not know.
The force of attraction between bodies.
microWave radiation The background radiation that is found everywhere in space, and whose existence is used to support the Big Bang theory.
molecUle A group of two or more atoms held together by chemical bonds.
gravity
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