Facts on Fire

Our Sun is orbited by a lovely array of planets and they are widely diverse- big, small, airless, rocky, gaseous, hot, cold, and more. That makes us think that may be forming planets is easy with so many varieties to choose from. Even if making planets is hard, there are so many stars in the sky that it’s hard to believe our sun is the only one. Astronomers have fretted over this for a long time, but trying to find such planets is hard. The biggest problem is any such planets would be faint, far away from being able to see one in a telescope would be like trying to spot a firefly sitting next to a searchlight. Imagine two kids, one big and one small, facing each other. They clasp hands and start to spin around. As they do, the little kid, who weigh less, will make a big circle, and the bigger kid will make a small circle. The same would be true of a star and planet. As the planets orbit the star, it makes a big circle or ellipse. But the planets have gravity and it ...

At first, glance stars pretty much all look alike. Twinkling dots scattered across the sky. When we look closely we see the difference. Some look brighter and some look dull, sometimes that due to them being at different distances but it’s also true that stars emit a different amount of light too. If we look through Binoculars or take pictures of them, we'll see that they're all different colors, too. Some looks white and some looks red, orange. A spectrum is a result when we divide the incoming light from an object into individual colors or wavelengths. This reveals the vast amount of physical data about the object. But in the late 1800s we were only starting to figure out, Interpreting stellar spectra was a tough problem. The spectra we measure from the star are a combination of two different kinds of spectra. Stars are hot, dense balls of gas, so they give off a continuous spectrum; that is they emit light of all wavelengths. However, stars also have an atmosph...

Everything we understand about the Universe comes from light emitted or reflected by objects. It'd be nice if we could get actual samples from them: physical specimens we examine in the lab. Well, sometimes the Universe can be accommodating and allows us to hold it in our hands. If we go outside on a clear dark, moonless night chances are very good if we see a shooting star. A fiery dot leaving a long glowing trail behind it. What we’re actually seeing is a tiny bit of interplanetary debris: rock, Ice or Metal ramming through the Earth’s atmosphere, heated to incandescence. Most are faint but some can be astonishing bright. Shooting stars aren’t actually stars, Sometimes it seems like astronomers use different names for objects to keep things as confusing as possible. In this case, the actual bit of solid stuff coming from space called Meteoroids . The phenomena of the meteoroid getting hot and blazing across the sky are called Meteor and when it hits the ground, we...

The empty space past Neptune isn't exactly empty. We know that comets come in two varieties: Those with orbit periods of less than 200 years, which tends to orbit the sun in the same plane as the planets, and those with longer periods which have orbit tilted everyway. This is something of a problem: comets lose material when they get near the Sun. Over the course of millions of years, these comets should evaporate! And yet here we are 4.56 billion years after the solar system's birth and comets still appear in our skies.  Where the comet come from? 4.5 Billion years ago our solar system formed. Coalescing our of a flat disk of material around the sun, the inner planets were warmer, smaller and rocky while the outer planets were in a region that was colder, and grew huge. Out there in the chillier part of the solar system, water comes in the form of ice mixed in with dust and other stuff. These bits would collide and stick together, growing bigger. Some g...

Comets                                                                                                                                                                      Comets have been seen in the sky since antiquity. Comets Halley, for example, is shown in the Bayern Tapestry, which depicts the Norman Invasion of the British Isles in the year 1066. It was seen by Ancient Chinese and Greek too. In general, and like everything else in the sky, comets were consider omen or Harbingers of human events. Sometimes they were good omens. William the Conqueror liked ...

Asteroids  When we look at the diagram of the solar system, we'll see a big gap between Mars and Jupiter. A few centuries ago, that bugged Astronomer; they really wanted to be a planet there. On the first day of the 19th century January-1, 1801 Italian Astronomer Guiseppi Piazzi found a point of light moving at just the right speed to be the desired planet, but it was just a dot, and too faint to physically to be a terribly big object. He suspected it might be a comet, but follow up observations showed up it wasn't fuzzy. The object was given the name Ceres. A little over a year in 1802, another one was found then in 1804, astronomer spotted a third one and the fourth one in 1807. It was becoming clear that a new class of solar system object had been discovered. Given they were all dots in the telescope of the time, points of light like stars. They were given the name " Asteroids " which literally mean star-like. By the end of the 19th century, m...