As a space enthusiast, you have probably heard the terms quasar, pulsar, and neutron star before.
But, what is the difference between these three amazing space phenomena? What makes each of them unique?
This article will discuss the three terms in detail, provide some interesting facts about them and explain how and by whom they were discovered, and how these discoveries have impacted our knowledge of space.
What Are Quasars?
Quasars are very bright, but they’re not stars. Quasars are thought to be young galaxies, and they emit huge amounts of radiation across the whole electromagnetic spectrum.
They’re also far away, so we see them as they were when our Universe was young. The oldest known quasar is J0313-182.
Its distance is about 13.3 billion light-years. Therefore, we see this object as it was just 671 million years after the Big Bang.
Quasars are believed to be the most powerful objects in the universe and some astronomers think that they are the first step toward becoming a galaxy.
Quasars are very bright objects because they contain huge amounts of fuel in the form of massive clouds of gas.
This fuel is used by the central object to produce light. Quasars are located near the center of a galaxy. They are so far away from us that we only see the active nucleus, or the core, of the galaxy.
We don’t know what kind of galaxy it is, because we only see the bright core of the galaxy, so it’s like seeing the headlights of a car at night:
we don’t know what kind of car it is. But we can tell that there is a car driving somewhere nearby.
Quasars are powered by supermassive black holes. These black holes have masses of millions to billions of times more than the Sun.
A typical mass for a supermassive black hole is 10^9 solar masses (10^6 kg). For comparison, the average mass of an atom is 1/1000th of a gram.
There are two types of quasars: radio quiet and radio loud. Radio quiet quasars do not show any signs of activity on their surface, while radio loud quasars have jets coming out of their nuclei.
Jets are streams of plasma ejected from the center of the quasar. Radio loud quasars are much brighter than radio quiet ones.
What Are Pulsars?
Pulsars are bright rotating neutron stars that shine brightly. Their beams of light are only visible when they are pointed directly towards Earth.
They are referred to as the “lighthouses” of the universe and are used by scientists to help locate other planets.
A neutron star is a dead relic of a massive star. Neutron stars rotate at high speed and are highly magnetic, and astronomers can detect them using radio pulses.
Pulsars are very powerful stars that emit radio waves. These waves are used to measure time. Scientists use them to make extremely accurate atomic clocks. Pulsars are used as timers because they rotate so quickly.
They help us search for gravitational waves, probe the interstellar medium, and even find extrasolar planets in orbit.
It has even been suggested that spacecraft could use them to help navigate around the solar system.
On NASA’s Voyager spacecraft, there are maps that show the direction of the sun to 14 pulsars in the region.
If aliens want to find our home planet they couldn’t ask for a more accurate map. Gamma-ray Pulsars are very powerful sources of X-rays.
They are also very compact objects, making them difficult to study. A new type of star called a millisecond pulsar spins so fast that even light cannot escape its surface.
This makes it impossible to see the star directly. But astronomers found this object by studying the radiation emitted by the star as it rotates.
What Are Neutron Stars?
A neutron star is a super dense ball of matter that is crushed down to the size of Manhattan island. Neutron stars form when a massive star runs low on fuel and collapses.
The core of the collapsing star crushes together its protons and electrons into a neutron.
If a star’s core is less than 1 to 3 solar masses, then the neutrons stop the collapse, leaving a neutron star. Stars with more mass will continue to collapse into black holes.
Neutron stars are about 10 times denser than an atomic nucleus. They spin rapidly, giving off powerful beams of radiation. These beams sweep across our planet every few seconds.
Neutron stars are incredibly small but incredibly heavy. They weigh approximately one million tons (1 billion kg) yet are only 20 km (12 miles) wide, yet they are smaller in size than the Earth’s moon.
Neutron stars have incredible power. Some neutron stars are so hot that they glow red hot. Others glow blue or green.
Some neutron stars have temperatures over 100 million degrees Celsius (180 million degrees Fahrenheit).
Pulsars and Magnetars are both types of neutron stars, but they behave differently. Pulsars spin rapidly, and they emit radio waves.
Magnetars are very powerful magnets that rotate extremely fast, and they emit x-ray emissions.
When Were Quasars, Pulsars, And Neutron Stars Discovered?
Let’s take a closer look at when these were discovered now!
Quasars – Quasi Stellar Objects
In 1962 British astronomer Martin Ryle discovered two radio signals coming from different positions in our galaxy. At the time many scientists believed that all galaxies had radio components.
Ryle thought he had detected something completely new: an extra-galactic source. He was right.
The double-source he saw was the first evidence of what we now call quasars. Ryle named the sources after himself, QSO stands for quasi-stellar object.
Pulsars – Pulsating Radio Sources
On January 28, 1968, American radio engineer Jocelyn Bell observed a series of precise instants of “radio pulses”. She noticed that these came at regular intervals and were repeated within 5 minutes.
By analyzing the data she got from her antennae, she calculated that the source should be somewhere near the constellation Vela, between us and the Milky Way Galaxy.
Her employer, Princeton University suggested that the source could be a lighthouse-like object in the vicinity of our Solar System.
Since no other such signal had been seen before, the discovery was considered revolutionary. Over the years astronomers identified this strange source as a pulsar,
a rotating magnetized neutron star that releases energy through the emission of electromagnetic waves in the form of radio frequencies. This discovery was awarded the Nobel Prize in Physics in 1993.
While analyzing observations of X-rays emitted by objects, some researchers found that there were certain fluctuations in the timing of these X-rays which seemed to occur periodically.
When a neutron star collapsed, it would produce a burst of X-rays.
However, it wasn’t until 1967 that researchers managed to discover the actual nature of neutron stars. In 1967 Christos Gringa and Russell Hulse discovered the first example of a binary millisecond pulsar.
It’s worth noting that millisecond refers to 1/1000th of a second. These systems consist of a neutron star orbiting another compact body such as an ordinary star or a black hole.
Quasars, pulsars, and neutron stars can help us learn more about space and the beginnings of the universe.
With observations from large telescopes and advanced scientific research, we’ve gone beyond just studying our planet and have begun exploring the universe around us.
The future of space exploration looks promising, so hopefully, in time we will learn even more about the mysteries of quasars, pulsars, and neutron stars.
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