space – Super Facts

The Infeasibility of Manned Mars Missions

Superfact 141: Humans travelling to Mars and back using current chemical rocket technology is nearly impossible and extremely dangerous. It is in a completely different category from manned Moon Missions.

This photo was taken by NASA’s Viking 1 probe in 1976. The photo shows a slightly reddish planet with an enormous canyon, Valles Marineris. | The Infeasibility of Manned Mars Missions — Photo taken by NASA’s Viking 1 probe in 1976. NASA/USGS, Public domain, via Wikimedia Commons. The image comes from this site.

The exponential nature of rocket physics (the tyranny of the rocket equation), massive fuel and weight requirements, immense distances, the 500 days of waiting on the surface for Earth and Mars to align for a safe return, and severe hazards to human health, makes travelling to Mars immensely more difficult than travelling to the moon and back.

A realistic photograph of an astronaut standing on the surface of Mars, wearing a white space suit with reflective visor. The astronaut is holding a shiny silver sphere in one hand, which reflects the reddish Martian landscape. In the background, a Martian rover with visible details of its wheels and instruments rests on the rocky, dusty terrain. The red-orange soil and rugged landscape stretch into the distance under a pale, hazy sky. Hyper-realistic, sharp details, cinematic composition, vibrant colors, and immersive atmosphere. — Shutterstock asset id: 2680563665 by Shutterstock AI Generator.

We went to the moon. Russian cosmonaut Valeri Polyakov spent 438 days in space. We’ve sent spacecraft and landers, rovers and an aerial helicopter to Mars, so why could we not send people? It is just a few hundred times farther than the moon. Shouldn’t we be able to keep an astronaut alive for a couple of years for a Mars trip? It turns out that those questions are forgetting about several enormous obstacles. It turns out that the enormous obstacles facing a human Mars expedition are surprising if you haven’t investigated this topic before, and therefore I consider it a super fact.

The Tyranny of the Rocket Equation

The Earth and the Sun have gravitational fields that a rocket needs to overcome to move up into space. A good indicator of how difficult it is to leave a planet, or other celestial objects, is its escape velocity. The escape velocity is the minimum speed a rocket must achieve to break free from a celestial body’s gravitational pull and never fall back, without any further propulsion. The escape velocity for Earth is 11.2 km/s, for the sun it is 617.7 km/s, and for the sun starting from Earth’s orbit it is around 42.1 km/s. This means you need a better rocket to make it all the way to Mars because it is further away from the sun.

If the rocket is not powerful enough you need to add more fuel. The problem is that more fuel means that you make the rocket heavier, so you need even more fuel, etc. This is called the rocket equation. It is commonly called the tyranny of the rocket equation. Current chemical rockets using the best hydrogen-oxygen propellants already dedicate about 80% to 90% of their mass purely to carrying fuel.

Smoke and fire surrounding the Saturn V launch. | The Infeasibility of Manned Mars Missions — The photograph of the Saturn V launch vehicle (SA-506) for the Apollo 11 mission liftoff from launch complex 39A at the Kennedy Space Center. USA – July 16, 1969. Shutterstock asset id: 2599523569 by Rawpixel.com.

In fact, leaving Earth with a standard chemical rocket would become practically impossible if the planet’s radius were 50% larger. If Earth’s radius increased by 50% while maintaining the same density, its mass would grow by a factor of 3.375, raising surface gravity to about 1.5 times current levels. No matter how much fuel you added you could never leave planet Earth.

The picture shows a smaller Earth on the left and a bigger Earth on the right. Above the smaller Earth you see a small red rocket lifting up. Above the bigger Earth you see a small red rocket falling back down. — This picture illustrates the problem. You cannot get off the 50% larger Earth on the right with a standard rocket, no matter how much fuel you added. I generated this picture with the help of ChatGPT.

I should say that situation with Mars is a bit different from the supersized Earth situation above. We can send a standard chemical rocket spacecraft to Mars. Otherwise, we would not have been able to get any spacecraft to Mars. However, for a round trip we need extra fuel to get back up from Mars and that cannot be done without refueling. This means that you need orbital refueling strategies. For example, you can build refueling stations along the way, on the moon and on Mars, and then you have to transport the fuel there, before you begin the roundtrip. That is a lot of extra effort. You can read more here.

The Required 500 Days of Waiting on Mars

The distance to Mars is immense. When Mars is the closest to Earth it is on average roughly 60 million miles, which is 250 times farther than the moon. This is referred to as Mars being in opposition. When Mars is the farthest from Earth, it is 250 million miles from Earth, or 1,050 times as far as the moon. This is because Earth and Mars travel in orbits at different speeds. That’s a long trip. The picture below shows the planets and their orbits. See how Earth and Mars are far away from each other in this picture.

Detailed vector illustration of the solar system showing planets orbiting the sun with labeled names and elliptical orbital paths in a clean, educational style.Solar System Planets Orbiting Sun with Labels and Elliptical Paths Illustration. | The Infeasibility of Manned Mars Missions — Solar system. Shutterstock asset id: 2785416813 by Yeakub Dhali.

There are two obvious problems. First, after you land on Mars you cannot go back the way you came. You are going to have to wait for the best opportunity to fly back to Earth. A round-trip mission to Mars is estimated to take 900 to 1100 days. One estimate is 911 days (about 2.5 years): 174 days to get there, over 500 days waiting on the surface for planets to align for a safe return, and 201 days to fly back. The crew needs to be protected from the extreme radiation for 500 days, and fed for 500 days, and kept safe for 500 days without access to any Earth facilities.

Add to that the fact that Mars and Earth will be on the opposite side of the Sun from each other for two to several weeks (Mars solar conjunction) during which radio communication will be impossible. Any help needed from Earth during that time will be absent.

The Extreme Radiation and other Hazards

Last but not least the threats to the astronauts health are immense. Space radiation during a short trip to the moon is one thing. Being subject to space radiation during two and half years is quite another. Mars magnetic field is weak and its atmosphere thin, so you won’t get much help from that. To protect astronauts, you would need lead and water containment, which would add weight and additional fuel requirements. A very long time without gravity, maintaining safe ecosystems inside a rocket for two and half years, isolation and confinement, are all challenges that may not be survivable.

Conclusion

A manned Mars Mission is easier said than done. If you are interested, below is a YouTube Video that explains the details. Naturally, in the future we may have different kinds of technology, nuclear powered spacecraft, spacecraft utilizing the solar wind, advanced robots aiding astronauts, etc., that could make manned Mars missions feasible.

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Magnetars Super Magnets in the Sky

Super fact 75 : Magnetars are a type of neutron star with extremely powerful magnetic fields ranging from 10,000,000,000,000 Gauss to 1,000,000,000,000,000 Gauss. In comparison, Earth’s magnetic field varied from about 0.25 to 0.65 Gauss at the surface. In other words, the magnetar magnetic fields are from 20 or 40 Trillion times to 2 or 4 Quadrillion times stronger than Earth’s magnetic field at the surface.

A bluish neutron star surrounded by impressive looking fields | rs Super Magnets in the Sky — Magnetar – neutron star in deep space. For use with projects on science, research, and education. 3D illustration. Shutterstock Asset id: 1138434620 by Jurik Peter

The magnetic fields of magnetars are trillions of times stronger than the sun’s magnetic field, which is 1 Gauss on a quiet sun surface and 2,000 to 4,000 Gauss in sunspots. The magnetic field of an MRI’s machine is also incredibly strong (2,000 Gauss to 100,000 Gauss). It is thousands to over a hundred thousand times stronger than Earth’s magnetic field. That’s why you should not have metals around an MRI machine. However, the magnetic field of a magnetar is still hundreds of millions to tens of billions of times stronger than the magnetic field of an MRI machine, and the magnetic field is not confined to a small machine but surrounds a neutron star and stretches far out into space.

If you placed a magnetar halfway to the moon from Earth (a magnetar is around 12 miles in diameter), it would erase all the credit cards on Earth (see video below). If you get close to a Magnetar (1000 kilometers) cars and other metal would float up in the air and the atoms in yourbody would stretch into rods making organic chemistry impossible and kill you. If you placed a steel beam on the surface of a magnetar the magnetic field would pulverize it and destroy the atoms.

In 2004 a magnetar named SGR 1806-20 located 50,000 light years from our solar system (700 million times farther than the planet Jupiter) had a starquake disturbing the magnetic field and sending out a gamma burst that disrupted radio communication on Earth. I consider the existence of magnetars a super fact because the existence of these super magnetic monsters is shocking and not well known amongst the public, and yet their existence has been confirmed.

The picture shows a bright magnetar surrounded by a bluish gamma ray burst and it is all set to a background of stars. — On 27 December 2004, a burst of gamma rays from SGR 1806−20 passed through the Solar System (artist’s conception shown). The burst was so powerful that it had effects on Earth’s atmosphere, at a range of about 50,000 light-years. U Harvard, Public domain, via Wikimedia Commons.

What Are Neutron Stars and Magnetars?

A neutron star is the gravitationally collapsed core of a massive supergiant star. The collapse causes it to become super compact and relatively small by volume. As the name implies the atoms are crushed, and protons and electrons merge into neutrons, making the neutron star mostly neutrons. The typical diameter of a neutron star ranges from 10 to 25 km (6 to 15 miles) depending on its mass. Neutron star material is extremely dense.

A normal-sized matchbox containing neutron-star material would have a weight of approximately 3 billion tons, the same weight as a 0.5-cubic-kilometer chunk of the Earth (a cube with edges of about 800 meters) from Earth’s surface, or a very large mountain. In addition, the gravity on a neutron star is immense, about 100 billion to 200 billion times stronger than Earth’s gravity.

Magnetars are neutron stars with extremely powerful magnetic fields. They have the universe’s most powerful magnetic fields (trillions of times stronger than Earth’s) that power intense X-ray/gamma-ray bursts as its field decays, often seen as highly variable pulsars. They were first theorized in 1992 to explain Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs). As of July 2021, 24 magnetars have been confirmed. According to the video below 30 magnetars have been confirmed in the Milky Way. There might be 3,000 in our Galaxy.

At top there is some text stating “A neutron star is a dense core left behind after a massive star goes supernova and explodes. Though only about 10 to 20 miles (15 to 30 kilometers) wide, they can have three times the mass of our Sun, making them some of the densest objects in the universe, second only to black holes. A teaspoon of neutron star material would weigh 4 billion tons on Earth. There are several types of neutron stars.” : Below the text at the top there is a picture of a magnetar, a pulsar and a magnetar plus pulsar. The text for each picture says: Magnetar - A magnetar is a neutron star with a particularly strong magnetic field, about 1,000 times stronger than a normal neutron star. That's about a trillion times stronger than a normal neutron star. That's about a trillion times stronger than Earth's magnetic field and about 100 million times stronger than the most powerful magnets ever made by humans. Scientists have only discovered about 30 magnetars so far. Pulsar - Most of the roughly 3,000 known neutron stars ae pulsars, which emit twin beams of radiation from their magnetic poles. Those poles may not be precisely aligned with the neutron star's rotation axis, so as the neutron star spins, the beams sweep across the sky, like beams from a lighthouse. To observers on Earth, this can make it look as though the pulsar's light is pulsing on and off. Magnetar + Pulsar – there are about six known neutron stars that are both pulsars and magnetars. | Super Magnets in the Sky — Courtesy NASA/JPL-Caltech, Attribution, via Wikimedia Commons

Magnetar YouTube Video

Other extreme stellar objects

I wish all of you Happy Holidays and Happy New Year

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The Betelgeuse Supernova

This is a submission for Kevin’s No Theme Thursday

Supernova

A supernova is an explosion of a star so violent that it can outshine an entire galaxy. It can occur when a super massive star’s core contracts (the death of the star) and as it reaches a critical point it triggers nuclear reactions that cause the star to explode. Alternatively, it can occur when a white dwarf star is triggered into runaway nuclear fusion by a collision with another star.

Depending on how far away the supernova is it can be as luminous as a bright new star, the moon, or a second sun. It occurs suddenly and lasts for several weeks or months before fading away. If a supernova shines bright enough, the other stars in the sky will vanish from view. We can’t see the stars during the day, not because of the blue sky, but because of the ambient light from the sun.

This is also one major reason photos from space often lack stars in the black sky. If a supernova is close enough to earth it could destroy earth. Luckily there are no super massive stars close enough to earth to pose a risk.

A picture of the Andromeda Galaxy with a bright white light near its center. The bright light is almost outshining the entire galaxy. — Supernova explosion in the center of the Andromeda galaxy “Elements of this image furnished by NASA” It is essentially an enhanced photo of a supernova explosion in a neighboring galaxy. Stock Photo ID: 2495486227 by muratart.

The Betelgeuse Supernova

Betelgeuse the bright red star in the constellation Orion is thought to be close to going supernova, and when it does it will be about as bright as half a full moon in our sky but concentrated in a point. What does “close” mean? Some astronomers say within decades, some say within a few thousand years. Could Kevin’s beautiful picture above depict this future event?

We are stardust

The first stars in the Universe were made of 75% hydrogen and 25% helium and trace amounts of Lithium, just like the entire Universe at the time. Heavier elements that could form rocky planets or other solid celestial bodies did not exist.

However, inside the cores of these stars, heavier elements such as carbon, oxygen, and iron were formed by fusion. These early stars are referred to as first generation stars. They tended to be large and ended their lives in massive supernova explosions. The dusty remains of these explosions became the building blocks of the second and third generation stars we see today as well as the planets, our bodies and all life. We are stardust.

The picture consists of two pie chart graphs representing stars. The left one is a first-generation star with one pie for the 75% hydrogen and one pie for the 25% helium. — The first-generation stars consisted of 75% hydrogen and 25% helium and trace amounts of Lithium. A second or third generation star like our sun is still mostly hydrogen and helium but also many other elements. The rocky planets circling the sun are mainly elements heavier than hydrogen and helium. Image credit NASA, ESA, CSA, STScI.

Finally, a 33 second YouTube video illustrating a Supernova (the creation of the Crab nebula)

Would you like to see Betelgeuse explode into a supernova in your lifetime?

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The Bizarre Reality of Black Holes

Superfact 15: A black hole is a region of spacetime wherein gravity is so strong that nothing can escape it, not light, not anything. There are different kinds of black holes. We don’t fully understand black holes, which makes them very interesting to science. The boundary of no escape is called the event horizon. Black holes are invisible. They are truly black. However, we can see what they do to their environment as they consume surrounding matter. Below are some bizarre facts about black holes.

Time runs much slower closer to a black hole.
An object falling towards a black hole will become redder, faint, then infrared, then invisible and all its movements and clocks will freeze.
From the perspective of an outside observer, time appears to stop for someone reaching the event horizon of a black hole. Time will continue for someone falling in.
At the center of a black hole may lie a gravitational singularity, a region where the spacetime curvature becomes infinite. However, since we cannot peer into a black hole we cannot know.
The largest known black hole (TON 618) is more than 287 million times more massive than the most massive known star (R136a1).
If our planet earth collapsed into a black hole, it’s diameter would be 1.75 centimeters or 0.69 inches in diameter. The diameter of the largest known black hole (TON 618) is 242 billion miles, which is more than one million times larger than the distance from the earth to moon.
There are supermassive black holes located at the center of most large galaxies, including our Milky Way. The Milky Way’s black hole is about 4 million times the mass of the Sun.
Astronomers estimate that there are around 100 million black holes in our Milky Way.
When an object (maybe a spaceship, or a person) approaches or falls into a black hole the difference between the gravity on the parts closer to the black hole and those further away will be so large that the object is stretched and ripped apart. This is called spaghettification.
Stretching from the event horizon and out another half radius of the black hole is a region called the photon sphere. In the photon sphere light will travel in a non-stable circular orbit around the black hole. Light will go around and around for a while. If you are in the photon sphere you might be able to see the back of your head.
Above is just a small sample of weird black hole facts.

A black hole sucking in a planet — The understanding of black holes requires the General Theory of Relativity, and it is still a lot we don’t understand about them. Stock Photo ID: 2024419973 by Elena11

The Bizarre Reality of Black Holes

I chose the Bizarre Reality of Black Holes as a super-fact and included the ten facts above because these facts are shocking and yet not well known. Below is a photograph of a supermassive black hole at the center of the galaxy M87 taken by the event horizon telescope in 2017. To create the picture below image processing was needed. It is the first photograph of a black hole. This supermassive black hole is an estimated 6.5 billion times as massive as our sun, and 28 million times as massive as the largest known star.

Below is an animation created by NASA that depicts what an observer falling into a black hole would see.

The fact that from the perspective of an outside observer, time appears to stop for someone reaching the event horizon of a black hole seems to prevent anything from falling into a black hole from an outside perspective. How does anything ever get inside the black hole if it freezes up at the event horizon? Black holes grow, they collide and merge, so clearly things can get inside, right? But how? As I tried to find the answer to this question, I found that I was far from the only one asking this question.

A black hole with an orange accretion disk is approached by futuristic starship. — Realistic spaceship approaching a black hole. This content was generated by an Artificial Intelligence (AI) system. Stock AI-generated image ID: 2448481683 AI-generated image Contributor Shutterstock AI Generator.

I searched physics forums trying to find the answer to this question. There were a lot of discussions but no clear answers. Some said, nothing falls into a black hole. Everything accumulates on the event horizon from the outside perspective and that’s how the event horizon and the black hole grows. The observer crossing the horizon essentially jumps infinitely far into the future, or into a different universe, that’s how he can pass through the event horizon.

Others said that the black hole is not static, it grows, and it shrinks from Hawking radiation, and this complicates the equations so that objects can enter the black hole even from an outside perspective. I have a few physics books on black holes that I have not finished reading. If I learn something better, I will update this post.

A depiction of a black hole surrounded by a space-time geometric grid that is bending due to gravity | The Bizarre Reality of Black Holes — AI-generated image Description : Space Black Hole Blue Illustration Gravity Geometry Vast Line. Stock AI-generated image ID: 2457551367 by AI-generated image Contributor Shutterstock.AI

In the image above the grid demonstrates how a black hole is distorting space-time. Other strange facts about black holes are that they are slowly evaporating through what is called Hawking radiation.

They come in different sizes. The smallest known black hole (XTE J1650-500) has a diameter of approximately 15 miles. Perhaps scariest of all, black holes are nearly undetectable unless they are feeding on star dust or tugging on nearby stars. That means one hungry black hole could be zipping right through our solar system without us knowing. Considering there are an estimated 100 million black holes in our Milky Way space travel might be scary.

Addressing a Good Question

After posting this post I received a question via email regarding this fact “If our planet earth collapsed into a black hole, its diameter would be 1.75 centimeters or 0.69 inches in diameter. The diameter of the largest known black hole (TON 618) is 242 billion miles, which is more than one million times larger than the distance from the earth to moon.” The person who asked thought that 1.75 centimeters was pretty tiny and was wondering how a black hole could be that small.

To create a black hole, you need extremely strong gravity and one way to increase the force of gravity at the surface of a planet is to compress all its mass into a smaller volume.

If you compressed all of earth’s gravity so its diameter was only half of what it is, it would be more compact, and the gravity would be four times stronger at earth’s surface. If you compressed it further so that the earth’s diameter would only be a fourth of its original diameter the gravity at the surface would now be 16 times stronger. If you keep compressing the earth until its diameter is only 1.75 centimeters the force of gravity at the surface would be 132,000 trillion times greater than it currently is according to Newtonian physics, and you would get a black hole.

I should say that it comes out differently with General Relativity and that number is different for different sized black holes. However, this calculation is for demonstrative purposes. For relatively small masses like a planet, you would have to compress so much that it becomes tiny before gravity becomes large enough to make a black hole.

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If you were an astronaut on an interstellar journey, would you be afraid of falling into a black hole?

We are Star Dust

Superfact 10 : We Are Star Dust

The matter in our bodies and our planet was formed by fusion in the cores of distant stars and then spread across the Universe by supernova explosions. This matter was later incorporated in second and third generation stars like our sun and its planets.

What do I mean by “We are Star Dust”? Let me explain. The first stars in the Universe were made of 75% hydrogen and 25% helium and trace amounts of Lithium, just like the entire Universe at the time. There were no heavier elements that could form planets or other solid celestial bodies. These early stars tended to be large and heavier elements like carbon, oxygen, and iron were formed by fusion in the cores of these stars.

Many of the first stars, called first generation stars, ended their lives in massive supernova explosions and the dusty remains of these explosions, including the metals formed in their cores, became the building blocks of the stars we see today. These second and third generation stars have planets and other smaller solid objects orbiting them, formed from the gas and dust (star dust) left over from the supernova explosions. So, we are star dust. The atoms formed inside the first-generation stars are now within us.

A colorful, nebula, a remnant from a supernova explosion on the background of a black sky full of stars. — Remnants of a recent supernova W49B, 26,000 light years away. Credit: X-ray: NASA/CXC/MIT/L.Lopez et al.; Infrared: Palomar; Radio: NSF/NRAO/VLA.

For those who know astronomy this may be basic information, but I’ve met many people who are unfamiliar with this information, and they are quite often surprised and astonished. That is why I consider this information a super fact. I can add that this process, the birth and death of first-generation stars, the supernova explosions, the disbursal of the matter, which later clump together to form new stars and rocky planets as well, takes many millions of years.

Bright white star surrounded by bluish rings | We are Star Dust — This is an Illustration of a supernova. Stock Vector ID: 2109918599 by Varunyuuu.

A Refresher

For those who need a refresher of things like stars and planets and galaxies. Our sun is a star, a third-generation star. It is much bigger than our Earth. If Earth is the size of a small pea or a caper, then the sun would be the size of a beach ball. However, our sun is not a big star, and it is only one star among between 100 and 400 billion stars in our galaxy the Milky Way.

Many galaxies including our own are disc shaped or look like spirals. If you imagine a dust storm cloud in which there are a thousand dust particles per cubic foot, each representing a star. Then this dust cloud would be 100 to 400 feet thick, and a thousand feet wide and long. I can add that there are between 100 billion to 2 trillion galaxies in the visible Universe. Also, the Universe is much bigger than the visible Universe and might be infinitely large.

The milky way galaxy stretches across the night sky. — A glimpse of our milky way galaxy. Photo by Stefan Stefancik on Pexels.com

As mentioned, orbiting around our sun there are planets, dwarf planets, moons, planet rings, asteroids, comets, meteoroids, interplanetary dust, etc. The star closest to the sun is Proxima Centauri, which is 4.24 light-years away, but it is too small to be seen. The stars that are visible in the night sky tend to be large stars that are not too far away.

Here in Dallas where I live you can typically see 15 stars with the naked eye, and you cannot see the Milky Way. That’s because of the light pollution. In northern Sweden where I grew up you could see 3,000 stars, our galaxy the Milky Way, as well as the Andromeda Galaxy on a clear night with the naked eye.

In 1885 a supernova explosion was recorded in the Andromeda Galaxy. Below is a constructed photo showing how it might have looked like if we had had better equipment back then. Notice that the supernova explosion is essentially outshining the entire galaxy. We are the result of the gases and dust spread by such explosions. You can also read more here.