When scientists look at a faraway celestial object, they are seeing it as it existed millions and millions of years ago, because it takes so long for light from the object to reach Earth.
“Variable star V838 Monocerotis”
credit: Hubble (NASA/ESA)
Astronomers can therefore “travel back in time” using equipment like the Hubble Space Telescope because light takes a long time to cross the vast interstellar distances in Space even though it zooms along at 299792.458 km/s
For example the rays of sunlight hitting earth this very second took 8 min 19.3 sec to travel from the Sun to Earth.
Similarly, Proxima Centauri is the closest star to our Sun and light from it takes 4.3 years to reach us on Earth.
So when Astronomers view Proxima Centauri through their telescopes they’re actually seeing it as it was 4.3 years in the past. If it imploded right now than we wouldn’t know until we looked at it 4.3 years from now.
Once telescopes became advanced enough to see outside our cluster of galaxies Astronomers could see see objects in space like galaxies as they were during the early age of Dinosaurs … a time that pre-dated our species.
Few things can let us see further out into the past than the Hubble space telescope operated by NASA and the ESA. Orbiting nearly 600km above us, Hubble is freed from the optical distorting effects of Earth’s atmosphere.
Sadly the lifespan of the revered Hubble telescope is nearing an end, however the good news is that a telescope arms race is taking shape around the world.
Astronomers are drawing up plans for the biggest, most powerful instruments ever constructed, capable of peering far deeper into the universe – and further back in time – than ever before.
“Ring Nebula NGC 6720”
credit: Hubble Heritage Team (AURA/STScI/NASA/ESA)
The building boom, which is expected to play out over the next decade and cost billions of dollars, is being driven by technological advances that afford unprecedented clarity and magnification.
In fact, the super-sized telescopes will yield even finer pictures than the Hubble Space Telescope, which was put in orbit in 1990 and was long considered superior because its view was freed from the distorting effects of Earth’s atmosphere.
“We know almost nothing about the universe in its early stages,” said Carnegie Observatories director Wendy Freedman, who chairs the board that is building the Giant Magellan Telescope.
“The GMT is going to see in action the first stars, the first galaxies, the first supernovae, the first black holes to form.”
The new telescopes will be so powerful that they should be able to gaze back to a couple of hundred million years after the Big Bang, which scientists believe happened 13.7 billion years ago. That’s where all the action is
– source: CNN
Explore the Universe From Your Computer
- Celestia – a free space simulation that lets you explore our universe in three dimensions. Celestia runs on Windows, Linux, and Mac OS X. Unlike most planetarium software, Celestia doesn’t confine you to the surface of the Earth. You can travel throughout the solar system, to any of over 100,000 stars, or even beyond the galaxy.
Over 10Gb of add-ons like textures, models or celestial objects are available at Celestia Motherlode
- Stellarium is an open source desktop planetarium for Linux/Unix, Windows and MacOSX. It renders the skies in real-time using OpenGL, which means the skies will look exactly like what you see with your eyes, binoculars, or a small telescope. Stellarium is very simple to use, which is one of its biggest advantages: it can easily be used by beginners.
- Microsoft World Wide Telescope – The WorldWide Telescope is a rich visualization environment that functions as a virtual telescope, bringing together imagery from the best ground- and space-based telescopes to enable seamless, guided explorations of the universe.
WorldWide Telescope, created with Microsoft’s high-performance Visual Experience Engine, enables seamless panning and zooming across the night sky blending terabytes of images, data and stories from multiple sources over the Internet into a media-rich, immersive experience.
- Google Sky – Google Sky includes a number of different ways to explore the universe. The initial view shows the visible universe and is a mosaic of images from the Sloan Digital Sky Survey, the Digitized Sky Survey and the Hubble Space Telescope