Tag: astronomy

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physics

All About Our Sun!

Image Credit: forbes.com

You may have heard people describe our sun as ordinary or not special. In comparison to other stars in the universe that may be true, but I submit that to those of us in our solar system the sun is quite special. Let us take a closer look at our sun and then decide if you think it is special or not. Our sun is the only star in our solar system. Eight major planets orbit the sun which is at the center of our solar system. The average distance between the earth and sun is 149,668,992 km or 93 million miles. Astronomers use this average distance as a unit of distance called astronomical units or AU. The distances in our solar system, galaxy, and beyond are so vast that it is easier to calculate distances using astronomical units than it is to use miles or kilometers. The sun sits at the center of our solar system and makes up more than 99% of the mass of the entire solar system. The diameter of our sun is 1.4 million kilometers (865 thousand miles), over one million earths could fit inside the sun. The sun produces heat and light which is needed for life on Earth. Without the sun the planet would freeze and life as we know it, would not exist.

What is Our Sun Made of and What Makes it a Star

Our sun is a G-class star that was formed some 4.6 billion years ago and is expected to last another 5 billion years. Stars form in a stellar nursery known as a nebula. A nebula is “… an enormous cloud of dust and gas occupying the space between stars and acting as a nursery for new stars (spacecenter.org) The sun, like all stars, is a hot ball of ionized gas. Our sun does not have a solid surface nor a solid core. The sun is 73.4% hydrogen and 25% helium by mass. The sun also contains trace amounts of carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur, and iron (ucf.edu). 

What makes our sun, or any other star a star? The object must be massive enough that nuclear fusion of elements can occur in the core due to the immense pressure inside the object. The smallest stars that exist are approximately 10 percent the mass of our sun while “high mass” stars are classified as stars having more than three times the mass of our sun. UY Scuti is the largest star ever observed and it has a radius that is 1700 times larger than our sun and it has a mass 7-10 times the mass of our star. 5 billion suns could fit into a sphere with the volume of UY Scuti.

The Layers of the Sun 

Image Credit: nasa.gov

The structure of the sun contains several different layers. The core of the sun is where nuclear fusion occurs as the sun fuses hydrogen into helium through a process called the proton-proton chain. This is a three-step process that results in fusing of hydrogen to produce helium. According to NASA “In the first step two protons collide to produce deuterium, a positron, and a neutrino. In the second step a proton collides with the deuterium to produce a helium-3 nucleus and a gamma ray. In the third step two helium-3s collide to produce a normal helium-4 nucleus with the release of two protons.” A byproduct of the nuclear reactions that occur in the core is the production of elementary particles called neutrinos. Neutrinos, according to scientificamerican.com are subatomic particles that is remarkably similar to an electron but has no electrical charge and a ridiculously small mass, which might even be zero. Neutrinos are one of the most abundant particles in the universe. These reactions are what produce the heat and light that we receive on Earth. The core of the sun extends about a quarter of the distance from the center of our star. The temperature within the core is over 15 million Kelvin.

The radiative zone is the next layer after the core. This region is where energy is carried outwards via radiation. The energy is carried through the radiative zone by photons. These photons, which travel at the speed of light, collide with other particles during their journey to the surface. According to suntoday.org, it takes “several hundred thousand years for radiation to make its way from the core to the top of the radiative zone.”

The convection zone is the outer most layer of the interior of the sun. This zone is much cooler than the core with temperatures of 2,000,000 C at the base of this zone while it is only 5,700 C at the top of the zone. This large temperature difference results in a phenomenon called convection. By definition, convection is “the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.” The convective motion in this zone results in “the generation of electric currents and solar magnetic fields (cora.nwra.com)

The photosphere is the first layer of the sun we can directly observe. This layer is 100 km thick and has a temperature range of 6500 K at the bottom and 4000 K at the top of the photosphere. This region is where sunspots, faculae, and granules are observed.  

The chromosphere is an irregular area located above the photosphere. Temperatures range from 6000 C to 20,000 C. In the chromosphere activity such as prominences, solar flares, filament eruptions can be observed. The reddish color seen in prominences is a result of the light given off from hydrogen at the higher temperatures.  

The outermost layer of the sun, often called the solar atmosphere, is the corona. This portion of the sun is visible during solar eclipses as the whitish edge of the sun. The corona features things such as loops, streamers and plumes that may be visible during a solar eclipse. The temperature of the corona is 1 million C. This is 1000 times hotter than the photosphere despite it being further from the core of the sun. In 1942 Swedish scientist Hannes Alfvén proposed a theory to explain this temperature anomaly. According to earthsky.org he “theorized that magnetized waves of plasma could carry huge amounts of energy along the sun’s magnetic field from its interior to the corona. The energy bypasses the photosphere before exploding with heat in the sun’s upper atmosphere.” 

The Death of Our Star 

Image Credit: schoolobservatory.org

The ultimate fate of a star depends on the star’s mass. High mass stars end their lives by going supernova and becoming a blackhole or a neutron star. Our sun is not massive enough to end its life in such spectacular fashion. When the sun exhausts its fuel, it will “expand into a red giant star, becoming so large that it will engulf Mercury and Venus, and possibly Earth as well (solarsystem.nasa.gov). According to an article published in Nature Astronomy the sun will “… produce a visible, though faint, planetary nebula” (earthsky.org). A planetary nebula is a bit of a misnomer as it is not related to planets. The term was coined by “… William Herschel, who also compiled an astronomical catalog. Herschel had recently discovered the planet Uranus, which has a blue-green tint, and he thought that the new objects resembled the gas giant” (space.com). A planetary nebula, according to Oxford languages is “a ring-shaped nebula formed by an expanding shell of gas around an aging star.” This phase of stellar evolution may last for tens of thousands of years which is a brief period astronomically speaking. Over time the faint planetary nebula will fade, and the sun will cease to shine, and its temperature and pressure will drop. The sun will become a white dwarf about the size of the earth. Is that the end of the cycle? Perhaps not. Astronomers believe that the white dwarf will continue to cool down to a point where it no longer emits light or heat. At this point it will no longer be visible and will be called a black dwarf. This cooling period is thought to take trillions of years so no black dwarfs exist. See my earlier post if you want to learn more about these fascinating objects.

Categories
astronomy Betelgeuse cepheid variable physics solar system supernova

Supernovas and the Death of Red Supergiant Stars

The red supergiant, Betelgeuse has been in the news recently because of its unexpected behavior. Astronomers have noted that since October 2019 the red supergiant had been dimming and the star is now less than 40% of its normal brightness. Before we discuss what this means for the star let me introduce you to Betelgeuse.

Betelgeuse is between 640-724 light years from Earth and is the alpha or brightest star in the constellation Orion. Betelgeuse and Bellatrix make up the shoulders of Orion, the Hunter. Betelgeuse used to hold the distinction of being one of the top 10 brightest stars in the sky but has fallen to below 20th since it began dimming in October 2019. Betelgeuse is believed to be between 9 and 10 billion years old with a solar mass that is 12 times more massive than our sun.

find betelgeuse,betelgeuse in orion constellation
Image: Akira Fujii

Red Supergiants

So what is a red supergiant star? Red supergiants are stars of a specific size that are nearing the end of their lives. These stars spend only about 10% of their lives as red supergiants while the prior 90% is spent as a massive main sequence star. These stars have a mass greater than 10 solar masses meaning these stars have more than ten times the mass of our sun. In these stars most of the hydrogen fuel has been exhausted and the core stops producing energy and gravity causes the core to contract. The layer of the star surrounding the core contracts and heats up to a high enough temperature to start fusing hydrogen to helium. The outer parts of the star expand as a result of the star burning hydrogen. The star is producing more energy than necessary to offset the collapse due to gravity. The outer layer expands to several hundred solar radii and the surface temperature cools as a result of the increased surface area. This temperature decrease gives the star its reddish color.

Courtesy of se.ssl.berkeley.edu

The Dimming of Betelgeuse

Betelgeuse belongs to a class of stars called Cepheid variables or variables. These types of stars, according to universetoday.com “are essentially stars that experience fluctuations in their brightness (aka. absolute luminosity)”. So this means that some dimming from Betelgeuse is to be expected. Betelgeuse is considered to be a semi-regular variable star or slow irregular variable star which means its brightness or luminosity fluctuates in fairly predictable cycles. One cycle lasts for approximately 420 days, a second longer cycle lasts for close to six years, and a third cycle lasts somewhere between 100 and 180 days. The current reduction in brightness is larger than expected which has led to questions about what this means for the red supergiant. Some scientists think that this dimming is simply an extended dimming period lasting longer than the 420 day cycle while others speculate that Betelgeuse may be heading towards its ultimate demise, a supernova explosion. The European Southern Observatory (ESO) posted a video comparing the luminosity of Betelegeuse from December 2019 to January 2020, you can view the video here: https://www.youtube.com/watch?reload=9&v=o1ls7Gr9LTE According to ESO “this video shows the star Betelgeuse before and after its unprecedented dimming. The observations, taken with the SPHERE instrument on ESO’s Very Large Telescope in January and December 2019, show how much the star has faded and how its apparent shape has changed.”

What is a Supernova and When Might it Occur for Betelgeuse?

According to nasa.gov, a supernova is “the explosion of a star. It is the largest explosion that takes place in space.” There is some speculation that Betelgeuse is nearing the end of its life and may go supernova in the near future. Let’s be clear about the meaning of “near future”. In our everyday life the “near future” may be a few days, a few weeks, maybe even a few months. Is astronomical terms, the “near future” may mean anywhere from a few thousand years to over a hundred thousand years. It is all based on your reference. Astronomers are comparing a few thousand years to the age of the universe which is estimated to be nearly 14 billion years old.

What Is A Supernova?
This Chandra X-ray photograph shows Cassiopeia A (Cas A, for short), the youngest supernova remnant in the Milky Way.
(Image: © NASA/CXC/MIT/UMass Amherst/M.D.Stage et al.)

When the iron core reaches its Chandrasekhar mass which is about 1.4 times the mass of our sun or 1.4 Solar masses, the pressure of the core can no longer hold up against gravity and the iron core begins to collapse. During this collapse the electrons and iron nuclei get mashed together and electrons combine with protons in the nuclei to form more neutrons. This combing of electrons and protons results in a decrease in pressure which speeds up the collapse. The collapse of the core takes a mere few thousandths of a second.

As the core of the star reaches a size of around 31 miles the core contains a gas consisting of 70% neutrons and 30% protons with a temperature of 100,000,000,000 K. This object is now a proto-neutron star. The outer layers are continuing to fall into the core and a stream of neutrinos are flowing out of the proto-neutron star. This flow of neutrinos results in an enormous release of energy causing the outer layers of the star to be blown away. This flow of neutrinos is responsible for 99% or this enormous energy and light is the remaining 1% of the energy.

The brightness or luminosity of a supernova is 10 billion times greater than that of our sun. A supernova may outshine its own galaxy for several days. So why aren’t we seeing supernovas all the time? Shouldn’t we be able to detect them by the enormous luminosity? Scientists have found that core collapse supernova only occur at a rate of 1 supernova per century per galaxy.

Types of Supernova

There are several different types of supernova. They are classified by the type of light that is emitted by star. This can be thought of as the chemical signature of the star. These signatures help astronomers determine what elements are present in or created by the star.

The first is called type 1a supernova. Scientists believe that this type of supernova occurs when white dwarf stars, those stars who had masses less than 1.5 times the mass of our sun, acquire more mass than its internal pressure can withstand so it heats up and goes supernova. A star that became a white dwarf would not normally be massive enough to go supernova. The white dwarf is thought to have gained the mass from colliding with another white dwarf of from a companion red giant.

The next type of supernova is the type 1b supernova. In this case the star had a mass at least 25 times the mass of our own sun. It certainly is massive enough to go supernova. This type of star is thought to have shed material from its outer envelope later in life which is why there is little hydrogen in its spectrum. This type of supernova does show helium in its spectrum.

Type 1c supernova contain very little hydrogen and helium and are formed the same way the type 1b supernova are formed. The difference between type 1b and 1c is the lack of helium found in the 1c supernova.

Type II supernova or core collapse supernova contain large amounts of hydrogen and helium in its spectrum. It is believed that large stars with masses are larger than 8 times the mass of our sun undergo this type of supernova. The massive explosion results in the creation of a blackhole or a neutron star. This is the type of supernova a red supergiant, such as Betelgeuse, will undergo at the end of its life.

Types of supernovas. Courtesy of astronomy.swin.edu.au

Why Do We Care about Supernovas?

It turns out stars only produce elements up to iron through the fusion reactions in their core. So that begs the question, where do elements heavier than iron come from? Well, the extremely large amounts of energy and the enormous temperatures associated with supernova explosions can cause fusion of the heavier elements. These heavier elements are shot out through the universe during the supernova explosion. Many of the elements we have found here on earth were created in the core of a star during a supernova. The elements that travel through the universe eventually are used to create planets, new stars and anything and everything else in the universe. According to nasa.gov/audience/forstudents “one kind of supernova has shown scientists that we live in an expanding universe, one that is growing at an ever increasing rate.” So that’s why you should care about supernovas!

Elements heavier than iron that are formed in a supernova explosion.
Courtesy of herschel.jpl.nasa.gov
Categories
astronomy Dark Matter physics

What is Dark Matter all About?

You may have heard of the terms dark matter and if you read my post from last week then I know you have heard of dark energy. Let’s talk about dark matter, what it is and why it is called “dark”. We know a black hole is called black because it is not visible to us and even light can not escape its gravitational pull. So is dark matter called dark because we can’t physically see it? Well, yes actually. We are unable to detect it directly and are only able to infer its existence by the effects it has on other objects. So let’s take a closer look at what dark matter is and what it does.

What is Dark Matter?

Dark matter comprises about 27% of the universe and dark energy makes up about 68% of the universe which means that only 5% of the universe is comprised of matter as we know it. This “normal” matter is called baryonic matter and is the matter we traditionally think of. Protons, electrons, atoms, anything that makes up everything from people to stars are made from baryonic matter. Dark matter, like dark energy is called dark because we are unable to detect it directly. Dark matter does not interact at all with the electromagnetic spectrum which means it does not reflect light, absorb light, or emit anything we can detect. As of yet no one has been able to directly observe dark matter. Dark matter is thought to be a previously undiscovered subatomic particle that does not respond to the strong or weak nuclear forces.

The key point here is that when scientists account for all the visible or detectable mass in the universe it doesn’t add up to be enough to account for the gravitational effects we observe. As stated above only about 5 % of the universe is normal or baryonic matter so that means the most of the gravitational interactions in the universe are a result not of baryonic matter but of something else. We call this something else dark matter.

Image result for dark matter dark energy pie chart
Courtesy of mcdonaldobservatory.org

There are several ideas as to what actually comprises dark matter. Speculation includes dim brown dwarf stars, white dwarfs, neutron stars and even black holes. Some scientists have dismissed theses objects as dark matter candidates because the gravitational effect needed to make up the “missing mass” doesn’t match the gravitational effect observed by these objects. Others have stated that the “missing mass” may simply be normal baryonic matter that is simply more difficult to detect.

WIMPs and MACHOs

Weakly interacting massive particles or WIMPS are theoretical particles of non baryonic matter which have somewhere between 10 and 100 times the mass of a proton yet interact very weakly with normal or bayronic matter so they are difficult to observe. If WIMPS are what make up dark matter then there should be 5 times as many WIMPS as normal matter. We should be able to detect them as they do interact with normal matter and the sheer abundance of them should allow us to detect them through collisions with each other. So far no WIMPS have been discovered.

Massive astrophysical compact halo object or MACHO is another candidate for the composition of dark matter. These are objects composed of bayonic matter but are difficult to detect because they emit very little to no light. These include the neutron stars, supermassive black holes, and brown and white dwarfs as mentioned earlier. Because they emit so little light one way to detect them is through gravitational lensing which we will discuss a bit later. It appears that there are not enough of these objects throughout the universe to make up the “missing mass”.

Image result for WIMPS and MACHOS dark matter
Courtsey of slideplayer.com

Other Dark Matter Candidates

Neutrinos are particles that aren’t associated with and don’t interact with baryonic matter. Neutrinos stream from the sun and pass through all regular matter, including us all the time. They are difficult to detect as they do not interact with matter. A new type of neutrino is thought to make up dark matter by some in the scientific community. Sterile neutrinos are a theoretical type of neutrino that have been proposed, they only interact with baryonic matter via gravity.

The Kaluza-Klein particle is a theoretical particle that would interact with the electromagnetic spectrum as well as gravity which should make them easy to detect. These particles are thought to exist in the fifth dimension making them difficult but not impossible to detect. The Kaluza-Klein particle is predicted to decay into particles we can readily observe, such as neutrinos and photons. As of yet though, none of these exotic particles have been observed.

How Do We Know Dark Matter Exists if We Can’t See It?

There are three pieces of evidence used to prove the existence of dark matter even though we can not detect it directly. The first is the speed of stars rotating on the outside edge of spinning galaxies. The stars on the outer edge should move at a much slower rate than those close to the center where most of the baryonic mass of the galaxy is contained. Direct observation has shown that these stars, at the outer edge of the galaxy, are moving at a rate very close to the rate of stars closer to the center. This has led scientists to the conclusion that there must be some mass distributed throughout the galaxy exerting a gravitational effect on the stars farther out from the center.

Stars, as it turns out, orbit their parent galaxy. By using Newton’s equations of force and the Universal Law of Gravitation we know that the force that causes the star to orbit in a circular orbit are equal to the force due to gravity on the star. If these forces were not equal then the star would careen into the center of the galaxy or fly off into space. Close to the center of a galaxy these forces are approximately equal as expected. Stars farther out from the center don’t appear to have these forces equal. So there has to be something going on to keep these stars in orbit. Dark matter is one such explanation.

Image result for dark matter graph
The graph depicts the discrepancy between the expected velocity (A) and actual velocity (B) of a star as the distance from the center of the galaxy, where most of the baryonic matter is located, increases. Courtesy of popscicoll.org

Gravitational lensing is a well documented phenomena in which massive objects distort the fabric of space time. Light must travel along this fabric and if there are massive objects distorting this fabric then the the source of light may appear shifted from the actual position as a result of distortions in space.

Image result for gravitational lensing
A visualization of gravitational lensing. Courtesy of agitatorgallery.com
Image result for gravitational lensing
An example of gravitational lensing. Courtesy of socratic.org
Gravitational lensing as a result of dark matter. Courtesy of nasa.gov

The third piece of evidence supporting dark matter is the the Bullet Cluster Galaxy merger. Two galaxies collided and due to only about 2% of a galaxy being made up of stars and roughly 5-15% being made up of gas and plasma there is a low probability of any baryonic matter colliding with one another. After the merger of the two galaxies gravitational lensing of background objects allowed scientists to determine where the accumulations of mass were located. It turns out that the dark matter was separated from baryonic matter in large enough quantities to cause gravitational lensing.

Image result for bullet cluster gravitational lensing
Courtesy of nanoqed.org

What if the Missing Mass is the Result of Something Else?

Not everyone is ready to accept that dark matter is responsible for the “missing mass” problem in the universe. Some scientists believe the problem isn’t that mass is missing but rather our theories and equations are incorrect. One particular idea is that Newton’s laws require a modification so that they match the observed behavior of galaxies. Those that support this idea have developed MOND or Modified Newtonian Dynamics as an alternative to dark matter. This theory suggest in situations when the acceleration rates are low Newton’s laws do not accurately describe the motion of galaxies. This alternative to dark matter is as still being developed and refined to better match observation.

Image result for dark matter theory
Courtesy of quantamagazine.org

Scientists know that the amount of baryonic matter which they are able to detect is not enough to hold galaxies together or keep stars from flying off into space rather than orbiting their parent galaxy. What is unknown is the precise mechanism causing the behavior observed by galaxies and stars. Dark matter is certainly the most widely accepted theory about our “missing mass” problem but it is by no means the only theory.

Categories
astronomy physics

Olber’s Paradox

Heinrich Wilhelm Olbers

Wilhelm Olbers was a German astronomer and physician who was born in 1758 and died in 1840. Olbers’ had several noteworthy contributions to the field of astronomy including developing a method to calculate the parabolic orbit of comets. Olbers’ primary focus was in searching for comets. According to Encylopedia Britannica a comet is ” a small body orbiting the sun with a substantial fraction of its composition made up of volatile ices.”

Olbers’ was the first to propose that a comet’s tail is always pointed away from the sun as a result of radiation pressure from the sun itself. Olbers’ is also credited with discovering a total of 5 comets as well as two asteroids, Pallas and Vesta. On March 6th, 1815 Olbers’ discovered a comet with a period of approximately 72 years. The period of the comet was calculated by his friend and colleague Carl Friedrich Gauss and verified by other astronomers of the time. Olbers comet, 13P/Olbers, next perihelion, which is its closet proximity to the sun, will be on June 6th, 2024.

A Scientific Paradox

A paradox, according to Merriam-Webster, is “a statement that is seemingly contradictory or opposed to common sense and yet is perhaps true.” Science is certainly not immune to experiencing a paradox. One of the most famous paradoxes is the grandfather paradox which appears to be a way for nature to forbid time travel to the past. It goes like this, suppose you go back in time and murder your grandfather before he and your grandmother conceive your father. By doing this your father and consequently, you will not be born. If you are not born then you could not have gone back in time to murder your grandfather so then you will be born. A resolution to this paradox is that if you kill your grandfather, you are actually killing him in different universe. Another possible resolution is based on quantum mechanics and the superposition of states. You can watch a short video from minute physics to see the description of the grandfather paradox and possible resolutions to the paradox. https://www.youtube.com/watch?v=XayNKY944lY This is just one example of a paradox in science there are many others you can find by executing a quick google search.

Olber’s Paradox

Courtesy of abyss.uoregon.edu

In 1826 Heinrich Wilhelm Olbers asked a deceptively simple question which became known as Olber’s Paradox. That question was “why is the night sky dark?” If the universe is both endless and populated with bright stars then the night sky should be blindingly bright at least as bright as the sun because every single line of sight must end at a star. If the universe is infinite then we should be able to see a star in every direction. Even if some stars that were further away were dimmer there would be more of them so the result should be a consistent luminosity across the sky.

So why isn’t the night sky uniformly bright?

Perhaps the most reasonable factor in the resolution to Olber’s paradox is that the universe is finite and that light from stars that are more than 13.7 billion years old are to far away for their light to have reached us yet. A second factor is that because the universe is not static but rather is expanding, light from distant galaxies is red-shifted into the non visible portion of the electromagnetic spectrum. The farther away a galaxy is from the earth the higher the red-shift of the visible light. So light from galaxies that are past a certain distance from us is red-shifted to the infrared portion of the spectrum which we can’t detect with our eyes. In summary, because the universe had a beginning, there aren’t stars in every direction, light from stars that are older than 13.7 billion years old hasn’t reached us yet, and because of the expansion of the universe resulting in red-shifting of visible light the night sky looks dark.

Categories
astronomy physics

Neutron Stars: What are they and why should we care?

Image result for neutron star
Courtesy of sciencealert.com

Neutron stars: One of the universe’s most exotic and bizarre objects.

Most people are familiar with black holes and understand that they are created when a massive star, one that is greater than 30 times the mass of the sun, dies. Stars that are similar in mass to our sun ranging from about .3 times the mass to 8 times the mass of the sun become red giants when they die. So what exactly is a neutron star? Neutron stars are the result of a collapsed star that is approximately 25-30 times the mass of our own sun. The star goes supernova at the end of the its life. When a star runs out of nuclear fuel and nuclear fusion within the core slows, the result is a decrease in pressure. This drop in pressure causes the star’s core to compress under the strain of it’s own gravitational forces. Without the offsetting pressure to maintain the stars structure the core collapses in a few thousandths of a second.

Neutron star via NASA
Courtesy of NASA

The core temperature of a star that has gone supernova may exceed billions of degrees Celsius or 100 000 000 000 K. The star undergoes a fantastic explosion that is called a supernova. The luminosity of a supernova may be up to 10 billion times greater that of our own sun. The supernova may even outshine its entire galaxy for a few days. The rate at which core collapse supernova occur is approximately 1 supernova per century per galaxy.

Once a star within the 25-30 times the mass of our sun has gone supernova, what happens to its left over core? One possibility is that the core stabilizes and becomes a neutron star. A neutron star is thought to be composed of a super-fluid an exotic friction free state of matter of neutrons. The electrons and protons inside the star have been compressed to create the neutrons found in the super-fluid state. A neutron star may be only 12 miles in diameter and have a mass of 1.3-2.5 the mass of the sun. So how did a star that was 25-30 the mass of our sun end up being a core that is only 1.3-2.5 times the mass of our sun? When the core of the star is collapsing the outer layers of the star get removed due to the large amount of energy that is released by the star. A large majority of the energy released by the star is in the form of neutrinos (99% of the energy) while the remaining energy released is in the form of light. The matter within a neutron star is so densely packed into the 12 mile diameter that a sample of the neutron star the size of a cube of sugar would weigh 1 billion tons.

Why should we care about neutron stars?

Scientists have long wondered where elements heavier than iron were created. Dying stars produce elements up to iron but little was known how the heavier elements were produced. As it turns out during a supernova, heavier elements including gold and platinum may be produced. In order for these heavier elements to be produced a neutron rich environment is needed. A process called ‘r-process’ or rapid neutron capture process is used to create these heavier elements. Neutron stars, as you might guess from the name, provide just such a neutron rich environment. One theory suggests that the merger of neutron stars is a mechanism for r-process and the creation of these heavy elements.

Interesting facts about neutron stars

  • The gravity of a neutron star is approximately 200 billion times greater than gravity on Earth.
  • The magnetic field of a neutron star is approximately 1 trillion times greater than on Earth.
  • The electric fields of a neutron star are 30 million times more powerful than a bolt of lightning.
  • Neutron stars rotate several hundred times per second with the fastest known neutron star, PSR J17482446ad, rotating over 700 times per second.
  • There are about 100 million neutron stars in the Milky Way galaxy.
  • There are 2 known neutron stars to host planets.