How old is light hitting earth

Well, you can do that at the eyepiece of an amateur telescope. Quasar 3C is an incredibly luminous object, which is brighter than individual galaxies, and powered by a huge black hole. That said, you can spot it with a 20cm aperture telescope.

A bigger telescope allows you to peer even further into space, and I once had the pleasure of using an eyepiece on a 1. Read more: An expanding universe and distant stars: tips on how to experience cosmology from your backyard. Earth is just 4. Without really trying, you can see years into the past. And with the aid of a telescope you can see millions or even billions of years into the past with your very own eyes. Portsmouth Climate Festival — Portsmouth, Portsmouth. Edition: Available editions United Kingdom.

Become an author Sign up as a reader Sign in. Brown , Monash University. Author Michael J. However, some intense ones can disturb the atmosphere where GPS and communication signals travel. X-class denotes the most intense flares. The number provides the intensity. For instance, X2 is twice as intense as an X1. The image showed a bright flash at the Sun's lower centre and extreme ultraviolet light in flares represented by teal colour in the image.

As the solar wind is intense, the second most powerful this year, the resultant northern lights should be visible from as far south as New York, Idaho, Illinois, Oregon, Maryland, and Nevada.

Young said the solar flare accompanied a coronal mass ejection CME , a huge eruption of radiation. Seeing auroras can be difficult, especially if you live in a big city filled with streetlights and other light pollution. Originally born as energetic gamma rays, after billions of collisions with matter, this radiation reaches the surface and escapes into space.

How old is sunlight by the time it reaches the surface? Most textbooks say that it takes light between , years and 50 million years to escape. You would be surprised to know that this simple, and very popular, question seems to be without a firm answer! The reason has a lot to do with the assumptions that textbook authors use in making the calculation. Most astronomers are also not particularly interested in a high-accuracy answer, so they tend not to bother doing the tedious calculation exactly.

It is actually a very complex problem in physics! Because the density of the sun decreases by tens of thousands of times from its lead-dense core to its tenuous photosphere, the typical distance a photon can travel between charged particles changes from 0. As a comparison, most back-of-the-envelope estimates assume that the sun's interior has a constant density and that the 'free path' distance for the photon is about one centimeter.

It is these estimates that find their way into many popular astronomy textbooks. The interior of the sun consists of three major zones, each with its own unique properties. Courtesy: Berkeley - SSL. Once you know, or assume, a typical distance between collisions, you also have to figure out how many steps the photon has to take to travel from the core to the surface.