Month: October 2018

The title of the this post is a fact. Our own mortality is, truly, inevitable. However, the “We’re” that I am referring to is our theoretical descendants, around 3.75 billion years from now. But many scientists believe that this event will not cause the end of Earth. In full disclosure, its much more likely that the death of our solar system’s sun will cause our planet’s death than what is discussed in this post.

Regardless, a possible cause of our descendants’ deaths is the collision of the Andromeda and Milky Way galaxies. We will start by establishing some facts about Andromeda, as many do not know as much about one of the closest galaxies to our own.

The Andromeda Galaxy.

The Andromeda Galaxy

Andromeda, the Milky Way, and Triangulum are the three largest galaxies in our Local Group of Galaxies. Triangulum is much smaller, but Andromeda and the Milky Way are approximately equal in size (we used to believe that Andromeda was much larger than us, however new technology for measuring galaxy mass has determined that it is much smaller). Andromeda is also the most distant astrological object you can see unaided in the night sky (although you need a great spot away from light pollution to see it).

Because of its similar mass to the Milky Way, the Andromeda and Milky Way galaxies are drawn towards each other through a mutual gravitational pull. This results in the Andromeda Galaxy hurtling towards us at at least 250,000 miles per hour.

I know, this sounds absolutely terrifying. Two galaxies colliding sounds like the end of all life on Earth. But many scientists believe that Earth will survive the collision, based on its position in the Milky Way, and the only major difference will be that our night sky will look entirely different. A video off of Business Insider is very interesting in showing the possible appearances of our sky.

But what will happen to the Milky Way?

Currently, our galaxy and Andromeda are spiral galaxies. This is a less common type of galaxy, and studying Andromeda has actually helped scientists greatly in determining the origin of the category. However, once the two galaxies collide, they will completely rip each other apart, parts of their galaxies shifting from their original positions as the supermassive black holes thought to be at the center of each galaxy meet for the first time. They will then throw each other away, and eventually come back together to form a massive elliptical galaxy (the most common shape of a galaxy in the known universe). (NASA Hyperwall released a great video on what this would look like.)

Ultimately, for our descendants, not much will change. They will probably be more focused on the imminent death of the sun (stay tuned for a post on that), as its predicted time of death is approximately 3.5-4 billion years from now.

However, personally, I am disappointed that I will not be able to see the night sky as it will look after the collision. I’m sure it will be stellar.

Sources:

https://svs.gsfc.nasa.gov/30955

https://www.businessinsider.com/milky-way-andromeda-galaxy-collision-space-nasa-hubble-2016-1

https://www.forbes.com/sites/jillianscudder/2016/11/27/astroquizzical-milky-way-collide-andromeda/#16009db96574

https://space-facts.com/andromeda/

Discovered by Geoffrey Marcy and R. Paul Butler in 2004, this oxymoron of a title refers to the planet Gliese 436 b.

Gliese 436 b is known as one of the smallest exoplanets (planets that exist outside of the solar system), very close to the radius and mass of Neptune. But even more interesting than its size relative to other exoplanets, is its distance from its sun.

Gliese 436 is a red dwarf star less luminous than ours, and is close enough to our solar system that it can be viewed in the zodiac constellation Leo. Gliese 436 b is only 2.5 million miles away from Gliese 436. For comparison, Mercury (the closest planet to the sun in our solar system) is nearly 36 million miles from the sun. The planet completes a whole revolution in only 2 days and 15.5 hours, and its surface temperature is around 439 degrees Celsius (for reference, the boiling point of water is 100 degrees Celsius).

But if the surface temperature is so much higher than the boiling point of water, how is there ice? Let alone, how can ice burn?

Scientists and astronomers have concluded that the form of ice that exists on Gliese 436 b is held in solid state due to the incredible gravitational force pulling from the planet’s core. The gravitational force increases with depth, and prevents the water from evaporating the way it does on Earth. For reference, there are many different states of water that we have not seen on Earth, because only three forms can exist in our environment. The water on Gliese 436 b is subject to an environment that makes the ice much denser than what we see here, and it is hypothesized as Ice VII, a cubic, crystalline form that has been manufactured in labs.

Similar to how when carbon turns into diamonds when exposed to immense heat and pressure, when the water on Gliese 436 b was exposed to the same conditions, it turns into “burning ice”.

Gliese 436 b defies every norm we would assume about a planet from a scientific perspective. Not only does it contain the hottest ice in the known universe, but being composed primarily of hydrogen not just on the surface but in its atmosphere, our exofriend should have significant levels of methane. However, it has 7,000 times less than it should, and a significant amount of carbon monoxide instead. Which is especially weird because carbon monoxide molecules should not be present to this degree, as it becomes scarce when temperatures exceed a certain threshold.

Yay for flaming ice poison air planet!

Furthermore, the planet (or its atmosphere) is evaporating. In a strange way, however. Gliese 436 b has a massive hydrogen cloud surrounding the planet that is suspected to be the result of immense pressure exerted by its proximity to Gliese 436. Scientists suspect that the planet has lost up to 10% of its atmosphere already, which they have analyzed through the ultraviolet eye of the Hubble telescope, as the cloud cannot be seen in visible wavelengths of light. The cloud itself is about 50 times the size of the parent star, and it does not get swept away by solar winds from Gliese 436 or is burned up because Gliese 436 is much cooler than normal stars. Similar to the tail of a comet, the hydrogen cloud follows Gliese 436 b along its orbit, and actually obscures the view of the planet from scientists, making it ever more difficult to learn more about this supposed scientific impossibility.

 

When people think about our planetary neighbor, the first thing to come to their heads is Mars. And why should it not? Mars is potentially inhabitable, and there has been some evidence of water on its surface.

Sadly, Venus is like the forgotten middle child. Not the closest to the sun, and not the planet closest to us, Venus is the second closest to the sun and similar to stereotypical middle children, it has been throwing some tantrums.

While it is similar in structure and size to Earth, Venus spins very slowly in the opposite direction, resulting in a day lasting 5,832 hours, or 243 days on Earth (a single day on Venus is actually longer than a year, which is 225 Earth days), in addition to the Sun rising in the West and setting in the East. Its atmosphere is coated with a thick layer of clouds blowing at hurricane force, sending them completely around the planet every five days. Due to the thick and acidic cloud layer, there is an intense greenhouse effect, making Venus the hottest planet in our solar system by far. It can melt lead (about 900 degrees Fahrenheit on its surface), and a glimpse beneath the clouds shows volcanoes and deformed mountains littering the ground.

Earth’s technology does not last very long on Earth’s surface, which means that a human being would probably perish even faster. However, there has been speculation of life existing in one of Venus’ top cloud layers, as the temperatures are more similar to Earth’s in those areas.

But why does this matter? Why is Venus the topic of this week’s post?

The short answer is comparative planetology – the comparison of planets in order to better understand one or both.

Venus, back in the 1920’s was thought of as a sister-planet to Earth. Astronomers and scientists believed it to be a lush planet, ripe for life. However, as time went on, we discovered more and more about Venus. Its atmosphere is 95% carbon dioxide, with the primary component in the clouds being sulfuric acid. Atmospheric lightning continuously flashes through the clouds, which extend up to 100 kilometers above the planet’s surface. The pressure on the surface is the equivalent of feeling like you were 1 mile deep underwater, and I have already addressed the temperature component.

We now know, as just expressed, that Venus is alien to us. The complete opposite of what we assumed it to be, the planet is what many would imagine hell to be like. It would reek of sulfur, with lava channels, massive craters (many meteorites burn up in the atmosphere, so the only craters that could exist/do exist are anywhere from 0.9 to 1.2 miles in diameter), volcanism, and frequent tectonic plate activity. Nothing from Earth could survive there.

Which is why we study it. By understanding why anything on Earth would die on Venus, particularly regarding the atmosphere, allows us to prevent the same result for Earth. Ancient Venus is thought to have had an ocean, possibly more qualities of life we recognize here, but it descended into chaos. Especially studying the runaway greenhouse effect, in addition to the role of aerosols in the atmosphere, and may end up helping us prevent Earth from becoming another Venus.