Space-exploration

Space Exploration 

  Stars and planets have fascinated people since ancient times, but it wasn’t until the 20th century that exploring space became possible. In recent decades we have sent astronauts to the moon, robotic spacecraft to the outer reaches of the solar system, and used huge telescopes to peer across the vastness of the Universe.

Observing the skies 

  For centuries, astronomers have observed the heavens with their eyes alone or used simple telescopes that magnify the view. But the visible light we see is just one part of a much bigger spectrum of electromagnetic rays that reaches Earth from space.stars and other objects also emit invisible radio waves, X-rays, infrared,and microwaves rays.modern telescopes can see all of these,and each type of radiation reveals something different.

Capturing light 

  Telescopes come in many different styles and designs,but basically all do the same thing collect electromagnetic radiaton from space and focus it to create an image. Earth atmosphere can block or blur the image,so some telescopes are located on high mountain tops or even launched into space


Radio telescopes 

  Huge,curved dishes are used to focus radio waves given out by sources such as galaxies, Pulsars,and black holes

Microwave telescopes 

  Microwave are short radio waves. By capturing these rays, telescopes can see ancient radiation from the big bang.

Infrared telescopes

  These instruments,some of which are sent into space,detect the heat from objects such as could of gas and dust.

Optical telescopes 

  Using large lenses or mirrors, optical telescopes gather faint visible light and can see much further than the human eye.

X-RAY telescopes 

  These telescopes captured high energy rays from extremely hot objects. X-ray telescopes only work in space.

Mapping the stars 

  Because Earth is surrounded by space,when we look at the night sky it seems as though all the stars are pinned to the inside of a giant sphere.Astronomers call this the celestial sphere and use it to map the position of stars and planets. Vertical and horizontal lines are used to divide the celestial sphere into a grid,just like the grid of longitude and latitude lines used to map Earth's surface.

Satellies 

  About 1,000 operational satellites orbit Earth, carrying out tasks such as beaming TV sinals around the world, gathering dat for weather forecasters , and spying for the military. Many thousands more pieces of space junk-old satellites, discrded rocket paqrts , and debris form collisions-also circle our planet. The growing cloud of space debirs is a hazard to spacecraft.