Clearly, these are not fully independent from each other or from astronomical physics (astrophysics). It is worth mentioning them in order to understand that astrophysics studies the formation and evolution of celestial bodies and structures at big scales along with the evolution of the cosmos itself.
What are the main experimental tools in astrophysics?
We are now going to review the characteristics of the basic objects used in astrophysics, namely, telescopes. We will, however, broaden this concept beyond the one we are used to.
Classical telescopes and the visible spectrum in astrophysics
When we think about astrophysics and astronomers, we usually turn our minds to someone looking at the sky through a telescope. This was the main observational tool until the 20th century, apart from our eyes. However, traditional telescopes have certain limitations: they are subject to human measurements and to the visible spectrum, that is, the range of light that our eyes can detect.
Although there are still telescopes operating in these frequencies, none of the observational work is now done by humans looking through a lens. The most prominent example of a telescope is the Hubble telescope (named after Edwin Hubble), which orbits the earth, taking measurements in the ultraviolet region, the visible region, and the near-infrared region.
The current concept of the telescope
Light comes in various frequencies, most of which we cannot see. However, in order to gather information about the universe, we need to measure every signal we can. Thus, telescopes able to measure other light frequencies have been developed in order to obtain more data. This allows us to analyse those frequencies, develop theories, and predict phenomena in our universe. Essentially, these telescopes are detectors of radiation.
Their characteristics, such as size, orientation system, presence of lens, or placement on the earth or in outer space, vary significantly since each serves a different purpose, which determines its basic features.
As a general rule, observation from outer space is more accurate since the earth’s atmosphere interferes with the signals and attenuates them. That said, some telescopes, such as those detecting long wavelengths, are too large to be flown into space, mainly because of the high costs involved.
Figure 1. Radio telescope
Why are stars relevant in astrophysics?
In the early universe, clouds of gas made of hydrogen (the most abundant element in the universe) and some other elements were its primary components. However, gravity, the only relevant force acting on an interplanetary scale, started to pull everything together.
When enough mass is pulled together, a fusion process starts, and stars begin to form. Stars are the most common astrophysical objects and, through their fusion processes, act as industries creating the rest of the elements found in the universe, apart from hydrogen and helium.
It should be mentioned that the clouds of gas and other elements commonly named ‘space dust’ still fill most of the universe and keep getting attracted to form new stars.
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