4C+29.30: The Invisible Universe Exposed

Narrator (April Hobart, CXC): Pictures of space are often gorgeous. But one of the most exciting things about them is that, very often, they show us things that are invisible to the human eye. This picture in particular does that. In the middle of the photograph lurks an invisible monster, called a super-massive black hole To make this invisible object even harder to study, it is hidden under a thick cloud of dust at the centre of its home galaxy! Even the bright blobs of colour you can see are patches of light that our eyes cannot detect naturally. The pink colour shows radio light, and X-rays are shown in blue.

A black hole is anything but empty space, don't let the name fool you. It is a huge amount of material packed into a very tiny area - this one has about 100 million times the mass of our Sun! Anything that wanders too close to a Black Hole is pulled into it with no chance of escape, including light. This is why we cannot see black holes, they are invisible even to telescopes that detect X-rays, radio waves and other types of light.

The only way we can spot black holes is by detecting its effect on other things. For example, in this picture, the brightest blue patches, along the edge of the galaxy reveal where a high-energy jet has ploughed into clumps of galactic dust. The jet was made up of particles that were heated as they were pulled into the black hole. This gave them energy and sent them speeding away from the black hole at millions of miles per hour! Two similar jets can be seen in pink, shooting to the North and South of the galaxy.

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HD 189733: NASA's Chandra Sees Eclipsing Planet in X-rays for First Time

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Narrator (April Hobart, CXC): HD 189733b: An exoplanet in orbit around a star about 63 light years from Earth. It has been nearly two decades since the first exoplanets – that is, planets around stars other than our Sun – were discovered. Now for the first time, X-ray observations have detected an exoplanet passing in front of its parent star. The observations, made by NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory, took advantage of the alignment of a planet and its parent star in HD 189733. This alignment enabled the observatories to observe a dip in X-ray intensity as the planet moved in front of, or transited, the star. This technique is the one used so successfully at optical wavelengths by NASA's Kepler telescope. In earlier studies using optical light, astronomers discovered that the main star in the HD 189733 system had what is known as a "hot Jupiter" around it. This means the planet is about the size of Jupiter, but in very close orbit around its star. The planet – that has been named HD 189733b -- is over 30 times closer to its star than Earth is to the Sun, and goes around the star once every 2.2 days. The new X-ray data suggest that this planet has a larger atmosphere than previously thought. This, in turn, may imply that radiation from the parent star is evaporating the atmosphere of HD 189733b more quickly than expected. The results on HD 189733 demonstrate how we need information from many different telescopes that detect different types of light to get a fuller picture of these mysterious worlds that we are now able to explore.

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