A Gaze into Astronomy #4

 

Advantages of Large Telescopes

Two of the major advantages of large telescopes are their resolving power and prowess in light gathering. Since large telescopes are wider than casual telescopes (and hence the name), the can resolve object much farther away with much greater quality. For instance, large telescopes resolve lunar cratelets on moon’s surface with higher precision than do smaller telescopes. Large telescopes are especially competent in collecting light. Due to their large aperture, they are able to garner more light which leads into the production of brighter images, helping astronomers inspecting the images.

Space Telescopes’ Advantages over Ground-Based Telescopes

Space telescopes have many advantages over their ground-based counterparts. First of all, they are above the blurring effect caused by the atmosphere, so the images are resolved at higher qualities than they would if they were taken from the ground. Satellite-borne telescopes are also free from light pollution, further improving the quality of the images taken. However, putting telescopes in space is laborious and expensive. It costs hundreds of millions of dollars to send telescopes to space not because of the manufacturing costs of the telescopes, but instead of fuel and spacecraft expenses. After sending the telescopes to space, space companies also need to ensure that they are operating healthily there and this costs even more. For example, instalment and maintenance costs of the Hubble Space Telescope approximate 5 billion dollars, a tremendous amount.

A Gaze into Astronomy #3

Where did the elements we see in the periodic table originate from?

The Sun’s light comes from a nuclear fusion reaction at the inner core of the Sun. All the elements in the periodic table are derived from hydrogen and helium, the two most essential ingredients of everything we see in the universe. Stars amass hydrogen and helium in their cores and squeeze them with such a force that hydrogen and helium turn into new elements through fusion. Then, the newly created elements fuse into other elements with higher atomic numbers, leading to the creation of every single element up until iron.

How do planets form?

Gas clouds accumulate. They start spinning in tremendous speeds; thus, their temperature increases. Then, they collapse under themselves and begin forming a dense region of cosmic material. This material accumulates, binding to itself all the matter available nearby. As the mass pile grows larger and larger, its gravitational force gets more powerful. Then, the mass begins sucking even more material.

How do neutron stars form?

Stars much more massive than the Sun can die and form neutron stars or black holes.

A neutron star is the collapsed core of a giant star and consists of a massive cluster of particles with extreme densities. Neutron stars are the second densest objects, right after black holes. Neutron stars have incredible pulsars that can be detected from Earth.

Black holes are points in space-time where gravity is so strong that virtually nothing can escape from it, including light. It is estimated that every galaxy has a black hole in its centre. Since black holes absorb light, they cannot be seen directly. Black holes consist of three layers: the outward and inner event horizon, and singularity. Singularity is the point in space-time where most of the black hole’s mass can be located at.

A Gaze into Astronomy #2

How do we “time travel” while observing the universe?

Light is fast; however, its speed is not unlimited. Therefore, lights from other objects take some time to reach us. Hence, the events that happened a long time ago become visible to us only after the light rays from those events have reached us. Consider a supernova explosion. If the explosion happened about 6 trillion miles away (about the distance of a light year), then we would see the explosion happening only a year after it has actually happened (lookback time). Thus, distant light is equivalent to old light for they present us events that happened mostly a long while ago after we first see them.

The Evidence for Big Bang

There is copious evidence for that the universe began in a hot, dense state 13.8 billion years ago. Here are two of them:

1.      Scientists know that the universe is expanding. If we trace back time, then there must have been a time when all the universe was squeezed into a single point.

2.      Microwave background is present wherever we look distant at the observable universe. As the universe expanded from its dense state, it left a glow that corresponded to its hot, early state as a dense point of squeezed mass and energy.

A Gaze into Astronomy #1

Astronomy's Difference from Other Scientific Disciplines

Astronomy differs from other sciences in many prominent ways. Firstly, in terms of age, astronomy is the oldest of all sciences. Its past is rooted in ancient civilizations’ desire to understand the night sky and the cosmos around them. Secondly, in contrast to the so called “lab sciences,” it is nearly impossible to perform physically monitored experiments in astronomy. In astronomy, the universe is itself an experiment. The whole cosmos – and all that is included in it – is an astronomer’s experiment. However, conversely to other sciences such as biology or chemistry, in astronomy we do not get to control this experiment due mainly to its scale and the time it needs to be carried out (for many stellar objects that concern astronomy are virtually thousands of billions of or more miles away from the Earth). Even before humans came into existence, the ingredients of this experiment and its setup were predetermined by the four forces and perhaps forces that we do not understand yet. Therefore, astronomy is and has been predominantly contingent on observation, rather than experiment.

Alleged Alien Visits and the Great Ancient Monuments e.g. the Great Pyramid of Giza

        Although the idea of alien visits to the world seems alluring, no evidence has been found yet to confirm that these visits actually happened. However, it is well-known by scientist that the ancients utilized astronomy for many purposes. Firstly, ancient sailors used the stars to help them guide their way while they were at sea – day or night. Secondly, ancient civilizations have used astronomy to shape their calendars and predict harvest times. Thirdly, astronomy had religious significance for those who studied it. For instance, it was believed by many ancient civilizations that constellations were there for mystical purposes and had strong connections with gods.

        The Stonehenge, Chichen Itza, and the Great Pyramid are major artifacts built by humans for astronomical purposes besides religious ones. For instance, it is now trivial that the Stonehenge had an astronomical use in addition to being a burial site. The stones in Stonehenge were carefully aligned so that they would point out to specific directions that have a great importance in keeping track of time and the night sky. And scientists have long believed that Chichen Itza was used as an observatory due to its altitude. Finally, about the pyramids, the pharaohs in Ancient Egypt ordered the ancient Egyptians to build the pyramids as tombs for the royals. However, this was not their sole purpose; today, it is known that pyramids had an astronomical end as well. In fact, it is known that the three largest pyramids in Giza stand for three stars in the belt of Orion.

-Bora