Category: Passion Blogs – Astronomy

The red planet is arguably the most interesting planet to us as humans, after Earth, of course. Mars is the next planet in our solar system and its radius is almost half of Earth’s, so it is smaller. This means that Mars exerts a lot less gravity than the Earth does. Yet Mars is the planet that astronomers always set their sights on as the first planet to colonize. Why is that?

Well, Mars is interesting because it is right at the edge of the goldilocks zone. It barely has an atmosphere, but if that atmosphere was developed and there were more greenhouse gasses in it, it could have liquid water exist naturally. Yet that is a long term goal with terraforming; shorter term goals would just have people living in a massive bubble colony and underground. Mars does have ice so there is water to use there. But more importantly, Mars is our next destination because life could have existed there too, a billion years ago. Mars used to be a lot more like earth, with rivers and rain, but over time solar wind’s stripped its atmosphere so now it only has a weak shell left. But in our search to find one of life’s greatest mysteries- are we alone- we might be able to find aliens in our own solar system on Mars or a moon like Europa and Enceladus. Of course, these aliens, which might just be fossils now, would not be like us. They wouldn’t be intelligent, instead, more like bacteria and other life from the RNA world. They would be extremophiles, most likely, that could survive in extreme conditions, just like the bacteria that live in heat vents and volcanoes.Of course, this is a big maybe, but this investigation would give humans a huge insight into how rare- or abundant life is in the universe.

What other reasons are there for humans to live on Mars? First, humans have always been a species built by exploration. If we hadn’t, most of us would not be in America today. Now that we have explored the Earth, the rest of our solar system is the next step. Exploration drives innovation, NASA has created so many inventions that are used by everyone today, including commercial cell phones, GPS, and microwaves. Finally, we should go to Mars for the simple selfish reason of species preservation. Organisms evolved over time to adapt and survive, and we must do so as well. The phrase “don’t keep all of your eggs in one basket” gets thrown around a lot, but it makes sense because we never know when the next meteor is going to hit the planet, and for all we know it could create an extinction level event like the dinosaurs. Getting humans on multiple planets ensures that humans will survive.

So why Mars? Because it is there.

Stars are massive balls of hot gas (mostly hydrogen and helium) and generate light and heat using nuclear fusion. They range from about 10,000 km (white dwarfs) to supergiant stars which are over a billion km in diameter. The sun, for comparison, is Approximately 700000 km across.

Birth of stars: After the big bang released all matter and energy into the universe, stars began to form. Stars are formed from clouds which have high concentrations of gas and other matter. These clouds are also known as a nebula. Nebula can be millions of light years in diameter and clump matter together, slowly becoming denser and the birthplace of stars.

Lifespan: In general, the larger the star, the shorter its lifespan.  Most massive stars live for about 10 billion years. Our sun is 4.5 billion years old has most likely another 5 billion years of life left. Some of the smallest red dwarf stars are believed to survive for 10 trillion years (although this cannot be tested since the universe is only 13.82 billion years old)Some supergiant stars have very short lifespans ranging from a few hundred thousand years to 30 million years.

Death: At the end of a star’s life, they die; Most normal sized stars (our sun included) will expand into a larger red giant at the end of their lifespan, after using up all of their hydrogen. When our sun does this, it will swallow up mercury and venus as it expands. After it expands, it collapses into an extremely small,  yet very dense white dwarf. Over time that white dwarf cools and dims (Earth-sized).

Supernovas: After massive stars run out of hydrogen and expand, they continue to complete nuclear fusion with more massive elements. The star cannot support itself with this fusion and explodes in dramatic fashion, shooting elements across the universe. Supernovas outshine stars and are the brightest thing in the sky for a couple weeks and then darken. Beatlegeuse is an example in our sky, where a supernova will occur soon. After a supernova explosion, all that is left of the past star is a very massive center. That can either result in a neutron star or a black hole depending on the mass of the initial star.

Neutron stars are about the size of a city and rotate very fast – multiple times a second. We can detect the rotation from the magnetic poles of the stars, and with telescopes, can “hear” the pulse of the star. They are therefore called pulsars.

Black Holes: When more massive stars supernova, they become black holes. They are super massive and dense spheres that are so massive that even light cannot escape its gravitational pull. Black holes can be tiny, or also massive; it is thought that there is a black hole at the center of each galaxy, which the rest of the galaxy orbits.

Life is precious, yet on Earth it is abundant. As it turns out, our planet is the perfect place for life to exist and thrive. We have water, a major building block of life as we know it, on our planet in its liquid form. From what biologists know about life on Earth, it needs this liquid water to survive. That is why many scientists theorize that the might have been life on Mars at one point since it used to have flowing rivers and that there might even be life on Europa, one of the four Galilean moons of Jupiter. What is so interesting about Earth, is that we fit directly in the middle orbit of our Sun’s Goldilocks zone. A Goldilocks zone is basically the orbital boundaries where water can form in its liquid state, thus making the planet a potential host of life. Mars is also at the far edge of our Sun’s Goldilocks zone because the majority of Mars’ water is frozen in ice caps or underground. Yet theoretically with a stronger atmosphere, Mars could once again harbor liquid water. Below is an image of our solar system demonstrating the goldilocks zone boundaries. 

When astronomers look into the stars and search for exoplanets, planets, not in our solar system, they have begun looking for potential planets that might just be able to harbor life. They do this through many methods such as the transit method and by solar radial velocity and from this have detected thousands of exoplanets from advanced telescopes. However, scientists have found that detecting potential life-harboring exoplanets is more difficult than it seems. First off, the majority of exoplanets are gas giants, just because they are easier to detect. These gaseous planets can be many times the size of Jupiter- our biggest planet. Next, the rocky planets detected have to have inside the star’s habitable zone- and have an atmosphere. The orbit can be determined by the planet’s period around the star, and atmosphere can be measured by light diffraction. So detecting these rocky “Super-Earths” that could have water was a fairly rare occurrence.

That was true until NASA developed new technology and sent up better telescopes to look for these specific exoplanets. A few months later, NASA had huge news- they had discovered TRAPPIST-1, a solar system with seven terrestrial planets, with three of them being in their dwarf star’s Goldilocks zone. This is a huge achievement and demonstrates how planetary systems can be common and also demonstrates how there must be life outside of Earth- if we keep finding planets that can house life as we know it, then there must be more life. Although TRAPPIST-1 is a little too far to get to (almost 40 light years) with current technology, it is an important system to study and hopefully travel to once technology gets better.

I wrote my first passion blog on gravitational waves and how we had detected them for the first time a year ago, and that the Nobel prize in physics had been awarded to the researchers who had made this discovery. The main criticism of this blog post is that I didn’t go into detail on what the implications for this groundbreaking discovery were.

It just so happened that this past Monday a new breakthrough was announced from NASA and the LIGO team who detect gravitational waves. They had detected something new- two neutron stars colliding. I discussed last time about how gravitational waves are detected by LIGO so I won’t do that here, but it is important to note that what was detected by LIGO was the ripples in spacetime.

First I want to talk about why these gravitational wave discoveries are important. Einstein theorized about gravitational waves many years ago, and the detection of them confirms many of his theories which had not yet been proven yet. This means that scientists can treat them like fact and build of those theories with absolute certainty that base way of thinking is correct. The discovery of gravitational waves also brings to the forefront a new type of astronomy. Many things in the universe are difficult for astronomers to observe, a simple example is black holes because their gravitational strength is so great that light cannot escape its event horizon. So the LIGO detectors give astronomers a new way to observe these phenomena without using regular telescopes. Finally, the LIGO detectors can be used as mean to confirm other discoveries and observations.

This is exactly the case in what was announced on Monday. LIGO had detected two neutron stars colliding, and then the Hubble Space Telescope was able to confirm by looking in the direction of the event and detecting the massive wave emission that was caused by the neutron star merger. What is a neutron star you may ask? A neutron star is a collapsed star of a star that was once 10-30 solar masses. However, it is so dense that that mass is compacted in a sphere the size of a city on earth. Just think of that- 20 suns inside a sphere the size of Philadelphia- it has a large gravity, which is why the gravitational waves were detected during the merger. These mergers between neutron stars are important to us because most heavy elements in the universe come from the energy release when neutron stars merge. So you can think of the merger that LIGO and Hubble observed as an explosion of gold and platinum and other heavy metals. Your phone has gold in it, and that gold was probably created from a neutron star collision or some other stellar event billions of years ago.

by kyle batra

The past couple weeks have been filled with news from Puerto Rico and Nevada so you might have missed the other important news of the week- the Nobel Prize. The Nobel Prize, named after Alfred Nobel who was famous for inventing dynamite, is a yearly award in many scientific categories and also peace and literature that honor the greatest achievements in those fields.

This year’s Nobel Prize in physics was awarded to three scientists, Kip Thorne, Rainer Weiss, and Barry Barish for their contributions in discovering gravitational waves, a concept that had been theorized by Einstein but never proven until very recently.

So what are these gravitational waves? Gravitational waves are very similar to other waves- light, radio waves, gamma rays… Yet they are a lot fainter and harder to detect (gravity is the weakest force compared to electromagnetic forces and the strong and weak nuclear force). Because of this, as Einstein theorized, we would only be able to detect massive gravitational ripples in spacetime, for example, when two black holes collide. Just a few weeks ago, just this occurred. Two black holes each about solar masses ended up merging far away in space, sending out huge ripples, gravitational waves, out in spacetime. We were able to detect these waves on earth, confirming that gravitational waves exist, which is a major discovery in physics and proves that Einstein was correct. This gives scientists a new way to observe the hardest observable object in the universe, black holes, and allows astronomers to look at other high mass objects like galaxies as stellar clusters as well.

In the photo above, one can see the large dip in spacetime that the supermassive black hole causes in spacetime. When multiple black hole’s collide, it causes the reverberations in spacetime which is what scientists look for and is what is known as gravitational waves.

How were the gravitational waves detected? Scientists constructed these two large-scale detectors named the LIGO interferometers which use a complicated set of angled mirrors to send two powerful lasers through miles of tubes. At the end, a detector is able to measure the exact wavelength of the laser, including where the bals and troughs are in the light wave. By looking at the variability between the two lasers, it can detect if a gravitational wave impacted the light waves. The tubes are very isolated so that nothing other than the gravitational waves could impact them. There has now been a third interferometer constructed in Italy, which was also able to confirm the previous detection of gravitational waves. By now having three detectors, astronomers can triangulate where in the sky the gravitational event is coming from. The final detector, named VIRGO, is smaller than the LIGO interferometers but is just as useful because of its ability to help triangulate the location of the event.