Halley’s Comet

Posted on April 7, 2023 by sydneyastr2110

I used measurements from Halley’s Comet for the impact homework, so I wanted to learn more about it. It certainly has name recognition, but I wanted to learn more about it. I found some great information from NASA that I figured I would share.

Halley’s Comet is named after an astronomer by the name of Edmond Halley. He figured out by using theories of Isaac Newton along with previous orbits of comets in 1531, 1607, and 1682 that the comets were one comet. Under this assumption, he predicted it would next be visible in 1758. His prediction was correct which resulted in the comet being named after him.

This marked the first time that a correct prediction was made for the return of a comet. This turning point in understanding comets made Halley’s Comet even more notable.

Halley’s comet is set to return in 38 years, 3 months, and 19 days from now given its orbit period of about 76 years and its latest appearance being in 1986. The image below shows the comet which is rather dark given its lack of reflectivity. This image is special in that it was the first spacecraft encounter with the comet which occurred by the Giotto spacecraft.

Image Credit: Halley Multicolor Camera Team (1986), Giotto Project, ESA, from NASA Photojournal

Interestingly, this comet has be orbiting for at least 16,000 years, and while a comet’s lifetime normally extends to 1,000 trips, Halley’s Comet does not appear to be reducing in size meaning we can expect it to be around for quite a while.

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Astronaut Bone Density

Posted on April 7, 2023 by Alex Diefenbach

(X-Rays of astronauts in space for extended periods of time: https://images.app.goo.gl/yfa81MRNQ1S5k5UL7)

When I was in 6th grade, I participated in a summer engineering competition called Zero Robotics through MIT. The objective was to create a code that would allow for droids aboard the International Space Station (ISS) to take pictures of research targets the most efficiently. In the process, however, we also got the opportunity to learn about what life is like aboard the ISS for these astronauts and we even got to Skype and hear their own accounts as well.

As you can imagine, there are many obstacles that these astronauts face by living far above the Earth’s biosphere and in a place with significantly reduced gravitational force. One of these principal caveats to the privilege of doing research in space is disruptions to normal bone density.

The human skeleton has two primary cellular mechanisms to maintain bone density. Osteoblasts and Osteoclasts. The former generates new bone tissue while the latter breaks the old tissue down. In order for Osteoblasts to continue their production of normal Osteocytes (typical bone cells), they must be subjected to pressure and weight: the kind they’d receive from the strain of gravitation on the body during everyday life on the surface of the earth.

However, as aforementioned, the forces of gravity at the altitude of the ISS are not nearly as strong as at the surface. See the law of gravitation here to understand the mechanics and mathematics of why exactly this is. This means that Osteoblasts are not receiving the normal amount of stimuli that trigger the continuity of bone cell generation. The Osteoclasts on the other hand, still continue their typical function of breaking down osseous matter. Leading to approximately a 1.5% bone density loss for every month spent in space, according to NASA.

To compensate for this, scientists researching aboard the ISS take “Bisphosphonate”: a medication used to treat bone density disorders such as Osteoporosis, in conjunction with calcium and mineral supplements. But one of their most used methods of maintaining their bone density is one used on Earth: exercise. The astronauts which we got to speak with on Skype at my engineering competition showed us several pieces of exercise equipment, variations of ellipticals and/or treadmills being some if I am remembering correctly. The strain from rigorous exercise the astronauts participate in helps to stall bone degeneration but this technique is not just for space people, a healthy exercise regimen provides the same benefits on the blue planet’s surface as well.

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The Fascinating World of Pluto

Posted on April 7, 2023 by theyounesadventure

Pluto, known as the ninth planet of the solar system, was reclassified as a dwarf planet in 2006. Pluto is one of the most interesting objects to study in our solar system. In this blog test, I will discuss the biggest moon Charon and the discoveries of the New Horizons spacecraft.

Pluto-Image by NASA

One fabulous thing about Pluto is that it has five moons but I will be only talking about the biggest one—Charon. Astronomer James Christy found Charon in 1978; it is Pluto’s biggest moon and the largest known satellite in terms of its parent planet. Christy spotted oddly elongated photos of Pluto and found that the elongation cycled back and forth over 6.39 days, which is the length of Pluto’s spin. Other photos of Pluto from years earlier that supported his discovery of the first known moon of Pluto were later uncovered by him. The fact that Charon is approximately half the size of Pluto and that their surfaces always face one another is known as mutual tidal locking. Every 6.4 Earth days, Charon orbits Pluto, and like Uranus, Pluto, and Charon are also tipped on their side. Pluto and Charon were captured by the Hubble Space Telescope in 1994. This telescope showed that they have different surface compositions and structures.

Pluto’s biggest moon: Charon – Image by NASA

Additionally, further secrets about Pluto were revealed in 2015 when the New Horizons spacecraft passed by the planet and took detailed pictures and data about it. It showed Pluton surface characteristics: large ice mountains and an area with a heart-shaped form. Also, the presence of cryovolcanoes and a potential subterranean ocean was further evidence of active geology discovered by the probe. 

New Horizons: 6 scientists looking at a computer screen react with amazement to the latest image of Pluto.

Scientists reacting to the latest image of Pluto taken by the New Horizon 2015 – image by Michael Soluri

As we continue to learn about the fascinating Pluto, we can learn more about the mysteries of our solar system. 

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The Kuiper Belt: Exploring New Horizons

Posted on April 7, 2023 by 7smessier45

Hello (again), and welcome (back) to my Astronomy Blog! Today’s post is about the Kuiper Belt and its objects. 

What is the Kuiper Belt? 

The Kuiper (Kai-per) Belt is a donut-shaped region beyond the orbit of Neptune. Within the Kuiper Belt, it is estimated that millions of icy objects (or even trillions of these objects, according to some estimates) orbit the Sun from a distance of 30-55 astronomical units. (One astronomical unit–or 1 AU–is the distance from the Earth to the Sun.) And although this region was first proposed by Gerard Kuiper in 1951, it was not confirmed until Dave Jewitt and Jane Luu discovered an object beyond Pluto’s orbit (44 AU) in 1992. Some of the best-known Kuiper Belt Objects (KBOs) include several dwarf planets, like Pluto and its moon, Charon. Other well-known KBOs include short-period comets (those with orbital periods less than 200 years) like Halley’s Comet.

Location of the Asteroid Belt and the Kuiper Belt, from NASA 

The Importance and Formation of the Kuiper Belt

Studies of the Kuiper Belt, and the objects within it, are incredibly important because they help inform and expand scientific understanding of planetary formation and our solar system’s formation. Presently, the Kuiper Belt is thought to include remnants of the early solar system and was formed approximately 4.6 billion years ago. Additionally, astronomers believe the objects in the Kuiper Belt could have become a planet in the absence of Neptune’s gravitational influence. 

A quick note regarding terminology

Although the Asteroid and Kuiper Belts share many similarities, it is important to know that the objects comprising the respective belts have different compositions and names. Objects orbiting in the asteroid belt–roughly located between Mars and Jupiter–are primarily made of rocks and metals; we generally call these objects asteroids. KBOs, in contrast, are predominantly comprised of ice–including methane, ammonia, and water ice. 

Stay tuned for the next post to learn more about how the New Horizons mission has enabled us to gather data about Pluto and the Kuiper Belt. 

 Until next time, 

7smessier45

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aurorae

Posted on April 7, 2023 by Emma Williams
Taken in Tromso, Norway (from USA Today)

The shimmering curtains of color that make up the Northern Lights are incredibly fascinating. For many (myself included), it is a life goal to get to witness this phenomenon in person.

The name Aurora Borealis has its roots in classical mythology. Famous astronomer Galileo Galilei combined the Roman goddess of the dawn, Aurora, with the god of the northern wind, Boreas. The lights also find themselves as playing in important role in oral history for many different cultures; for example, the Dene people believed that reindeers originated in the Aurora Borealis.

Despite this shroud of mythology and curiosity, scientists are confident in the cause of the Northern Lights!

Rather than the calm before the storm, aurora is the light show after the storm in space.

National Centers for Environmental Information, 2017

The sun is incredibly volatile (shocker, I know), and its chaos can create some disturbances that affect Earth’s magnetic field. These disturbances pull on the field like its a rubber band, and the recoil that results from the pull being released creates powerful ripples called Alfven Waves. These waves, created 80,000 miles from the ground, accelerate towards the Earth’s surface. Electrons ride Alfven Waves until they hit the thin upper atmosphere, where they collide with Nitrogen and Oxygen particles, get excited, and eventually calm down and release light. These resulting light emissions are what we know as the Aurora!

Your best chance of seeing these lights in person is close to one of Earth’s magnetic poles (different than the North and South geographic poles) when there is high visibility and it’s dark out. Have you ever been lucky enough to see Aurora in person? If you’re like me and you haven’t, I hope that someday you do!

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comets

Posted on April 6, 2023 by Emma Williams
Comet NEOWISE near Mt Washington in 2021 (from the New York Times)

The terms ‘asteroid’ and ‘comet’ are often used interchangeably, but in reality there are important differences between the two! The primary difference is in their composition; asteroids are rocky because they formed in the inner Solar System, and comets are more icy because they formed beyond the frost line!

Comets are visible every few years and appear with long, streaking tails. I, for one, did not realize how common comets actually were, but in doing my research for this blog post I found dozens of articles from the last few years about different sightings. I had only known about comets because that was my high school mascot!

Comets have played an important role in different cultures throughout history. The Babylonian “Epic of Gilgamesh” believed a comet to be the harbinger of tragedies, and ancient Mongolian legend thought that destruction was bound to accompany comets. Specifically in Hinduism, they played a dual role, representing not only good and regularity but also evil and disruption.

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Earth-like Exoplanet

Posted on April 6, 2023 by reachforthestarsbysam

The super cool story of a discovery of an exoplanet!

It’s so cool that an exoplanet look like this!

There has been an incredibly interesting and exciting discovery made recently! The James Webb telescope has discovered and photographed an exoplanet and collected data to validate its existence as an exoplanet. An exoplanet is an astronomical object that classifies as a planet but orbits a star other than our lovely Sun! This discovery and validation is not only interesting for the fact that it exists outside our solar system, it is incredibly similar to our own Earth in size. The Webb found that this exoplanet, professionally labelled as LHS 475 b, is 99% the size of Earth in diameter, and it is a rocky world much like our own. Very unlike our Earth, however, this exoplanet has an orbital period of 2 days around its star! The Webb distanced this exoplanet at about 41 million light years away, so it is very cool that such a similarly sized planet is so close!

Unfortunately for followers of the question of if there is another livable planet out there, this one is not looking too habitable. It has not been ruled out, but its atmosphere seems to be very methane-based like Saturn’s moon Titan!

I certainly did not know all this! I was taught a lot of this by NASA!

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An even grander Grand Canyon

Posted on April 6, 2023 by reachforthestarsbysam

Have you ever seen the Grand Canyon? Well take that image and toss it out because it’s not even close to the size of the canyon we’re talking about here!

An inside scoop on this canyon is supported by the image above, found at Business Insider!

The New Horizon’s mission has been one of the most exciting planetary explorations in recent history, as it dove deep into the outer solar system to explore and collect data on Pluto and its surrounding satellites. One of the most interesting parts about Pluto is that it is in a binary system with its largest moon, Charon, so when the New Horizons spacecraft went to study Pluto, it was also able to explore Charon and its properties. Similar to Pluto, Charon is made of ice and rock particles that condensed at the formation of the solar system, but as ice naturally does, it expanded. As Dr. Alan Stern mentioned in his talk on Pluto and the New Horizons mission, Charon expanded much like water that freezes in a glass expands, and when the water expands further than the capacity of the glass, the glass cracks. Something very similar happened with Charon: it expanded so far that the surface had to expand to relieve some of the pressure, which caused there to be a massive canyon on Charon’s surface (pictured above!). This canyon is nearly double the length of the Grand Canyon of the United States, and nearly 5 times as deep!

Information found here, and supplemented by the information given in a talk by Dr. Alan Stern!

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Blog 6 – Planet Nine

Posted on April 6, 2023 by Melanie Marszal

Unfortunately, “Planet Nine” does not refer to Pluto. However, its potential existence could explain the interesting movement of some objects in the Kuiper Belt.

Researchers at Caltech have found mathematical evidence of a large planet far out in our Solar System, which has been named Planet Nine. This hypothetical planet would be about the same size as Neptune and have about 10 times the mass of Earth. Its orbit would be very elliptical and about 20 times further from the Sun than Neptune on average.

Scientists believe there may be a large planet out in the Solar System due to the peculiar clustering of some Kuiper Belt objects that have been observed. This clustering seems like it could be caused by the gravity of a large planet, Planet Nine. Below is an illustration of the orbits of the clustered Kuiper Belt objects in question as well as the hypothetical orbit of Planet Nine.

An image from polispace of the orbits of Kuiper Belt objects along with Planet Nine.

Scientists hope to find concrete evidence of a planet out in the far reaches of our Solar System, but have yet to detect anything. It is possible that Planet Nine is not a planet at all, but instead a type of black hole. It is also possible that Planet Nine is made of dark matter. Some scientists think the key to finding it may be to look instead for moons or other matter orbiting around the planet rather than the planet itself. Regardless of what Planet Nine may be or if it even exists, astronomers will continue to search. Do you think we will find Planet Nine?

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Blog 5 – Pluto

Posted on April 5, 2023 by Melanie Marszal

Many of us may remember back when we were younger and Pluto was still considered to be one of the nine planets in our Solar System. What happened? Below I will explain the reasons Pluto is no longer considered to be a 9th planet as well as some arguments for why it should be.

Anti-planet:

The International Astronomical Union (IAU) has three criteria that are required for an object to be considered a planet:

  1. It is in orbit around the Sun.
  2. It has sufficient mass to assume hydrostatic equilibrium (a nearly round shape).
  3. It has “cleared the neighborhood” around its orbit.

Pluto meets the first two criteria, but struggles with the third. Since there are many other large objects in the Kuiper Belt where Pluto is found, Pluto is not considered to be gravitationally dominant in its orbit. For this reason, Pluto is considered to be a dwarf planet instead.

Pro-planet:

Although the IAU downgraded Pluto to a dwarf planet, some astronomers and planetary scientists disagree with the IAU’s criteria for being a planet. One planetary scientist argued that a planet should be defined by its intrinsic properties over its orbit. Pluto is a complex and active body, with oceans, moons, a multilayer atmosphere and more. Another scientist pointed out that since there are so many asteroids everywhere in our solar system, other planets also technically have not “cleared their neighborhoods.”

What do you think? Should Pluto be considered a planet? Why or why not?

Image of Pluto from NASA‘s New Horizons spacecraft.
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