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The Laniakea Supercluster

About the role of superclusters and voids in our cosmic web.

Many major scientific discoveries and exciting missions have marked 2019. One of the most awe-inspiring moments was the first picture of a black hole which we will all remember. We also spotted the first insterstellar comet “Oumuamua” which visited us from another star system. The first man-made objects named Voyager 1 and 2 ventured into interstellar space. The legendary Voyager probes have officially left our solar system and they discovered that the heliopause is not just a theoretical border, but an actual shield-like phenomenon, where the sun’s plasma bubble deflects most of the incoming cosmic radiation. This is good because it’s how our star keeps our faces from melting, funny as that might sound..

More news and further understanding of the universe awaits us as current missions continue. The Japanese spacecraft Hayabusa 2 is on its way home to earth, carrying samples from far away asteroid Ryugu. We are also closely following NASA’s Parker solar probe as it continues to get closer and closer to our sun. On the 29th of January it approached our star’s surface to a distance of 18.6 million kilometers. Next to this, we continue to watch SpaceX and Boeing while they prepare their rocket fairing capsules for the actual transport of astronauts to the international space station, and eventually to Mars.

Though this is all amazing and inspiring I was struck by an impressive YouTube video last week. It once again showed the vastness and emptiness of space while discussing our planets’ place in it. Understanding our solar system’s position in the grander scale of things will make you feel unbelievably tiny and insignificant. The amount of effort it takes us to map and visit the planets and objects within our own solar system is already enormous, could you imagine going beyond our solar system into interstellar space? (Matthew McConaughey & Anne Hathaway can). Without further ado, let’s talk about galaxies, clusters and groups.

Image Credit: Andrew Z. Colvin

When we talk about these subjects, a key definition is that these systems we call “clusters” or “groups” are gravitationally bound. To start out small, our galaxy, the Milky Way is a system of gas, dust and billions of stars. A step further and we see a galaxy group, these usually contain around a dozen galaxies. Our Milky Way is a part of the so-called Local Group which contains around 30 galaxies and was first discovered by Edwin Hubble in 1936. Within this group, the Milky Way and the Andromeda galaxies are the heaviest members. These two galaxies are expected to eventually collide and form one massive elliptical galaxy. During this collision, our solar system would probably survive as objects within these galaxies are still very far apart. What a sight it would be..

Moving further into space. In the 1950’s Mr. Gérard de Vaucouleurs found out that our Local Group is part of the Virgo Cluster. This cluster contains somewhere over a thousand individual galaxies. As the author of Universe Today, Fraser Cain describes: “these galaxies are all connected together by mutual gravity. Astronomers estimate that it contains a total mass of about 1.2 quadrillion times the mass of the Sun. It covers a total volume of space with a diameter of 15 million light-years across.” These volumes and masses are already hard to imagine, but let’s push even further. The most recognizable member of the Virgo Cluster is Messier 87, we know this galaxy because it holds the supermassive black hole of which we have recently seen the first-ever picture, which is truly awesome..

Something remarkable is that out of the center of Messier 87, a plasma jet forms. This jet of sub-atomic particles and electrons travelling at nearly the speed of light stretches out about 5000 light-years into space. The image above and to the left is taken by the Hubble Space Telescope. In the picture above and to the right you see the black hole at the center of Messier 87 which is responsible for blasting this jet into space.

Feeling small yet? Let’s move further out past the Virgo Cluster into the Virgo Supercluster..

That’s right, the Virgo Cluster is part of the even bigger Virgo Supercluster which is estimated to contain over a million galaxies. The Virgo Supercluster spans over 110.000.000 light-years in size and is just one of the millions of superclusters out there. Other famous superclusters are the Perseus-Pisces, Centaurus, Hydra and Coma superclusters.

These superclusters are forming the filaments of space, they act like curtains in space, shrouding the very large voids that are out there. These voids are areas in space where almost no galaxies or other massive objects are found. All together the superclusters are pulling all objects with mass, like planets, galaxies, clusters and such, towards them leaving huge voids in their midst. The balance between voids and superclusters is the largest visible way of how to perceive our Universe today. A very exciting role in this cosmic play, and the cosmic expanse, is reserved for dark matter and dark energy, but let’s discuss these topics in later articles.

The most impressive discovery where I wanted to talk about in this article is the Laniakea Supercluster. You might be thinking, yet another supercluster? Yes indeed, the Laniakea Supercluster is a gravitationally bound structure where our Virgo Supercluster is a small part of. I said small because Laniakea is about 100 times bigger, and heavier compared to the Virgo Supercluster. A team of scientists, led by R. Brent Tully of the University of Hawaii, found that Laniakea is where we can draw the line. Where we previously thought our supercluster ended with Virgo we found out we were part of an even bigger structure. Laniakea which means “immense heaven” is pulling all objects within its domain towards itself. With many galaxies drawn to an especially dense region within the supercluster called “The Great Attractor”.

Everything outside Laniakea is not gravitationally bound to the supercluster and is moving away from it as our cosmic web keeps expanding. Moving away from Laniakea we see the neighbouring supercluster called Perseus-Pisces as seen below.

Zooming out even further, we see that the structure of space as we know it is made out of voids and superclusters and is looking something like the image below. This cosmic web that we see in the image is expanding but the speed at which that happens is still heavily debated. The speed of the expanding of our Universe is very fundamental to many scientific theories, constants and statements some of which are:

  • How old is our Universe?
  • Which objects are ultimately bound together, and which are destined to drift away?
  • What lies ahead for the eventual state of our Universe?

In my following article I shall explain more about the Universe’s expansion, the role of General Relativity and Hubble’s Law herein.

Further reading on this topic:

Artemis – Goddess of the Moon and hunting

Artemis, according to Greek legend is the goddess of the Moon and hunting. She is the twin of Apollo and daughter of Zeus. So as to no small figure in myth and legend now Artemis’ name has re-surfaced as NASA introduced it latest ambitious space mission. In light of the renewed interest in space, or as some call it space race 2.0 the NASA administration has announced a new Moon mission. In the midst of a wild-west space scenario where privately owned tech companies try to outdo each other NASA too has to keep up. Tech companies are racing to get people into low earth orbit, to slingshot billionaires around the moon and eventually even put humans on Mars. In the middle of all this we have NASA which aims to once-again put men (not just man) on the surface of our Moon.

Artemis is a joined effort of NASA, US commercial spaceflight companies and ESA that is focused on crewed missions to the Moon with the goal of landing the first woman on the moon! And that is something worth cheering for! Why is this worth cheering for you might ask? Because it took way too long, and even as I am writing this article it hasn’t happened, before we get to see the first all-woman spacewalk. It is high time that we have an equal representation of mankind in space programs where women play an active role, equal to men and no longer as ‘hidden figures’. NASA now acknowledges this as part of their heritage and has taken steps in the direction of equality.

Anne McLain & Christina Koch

The mission of returning to the Moon is in its own right ambitious and must serve as a stepping stone for future missions to Mars. NASA states the following main objectives for the Artemis program:

  • “Demonstrate new technologies, capabilities, and business approaches needed for future exploration including Mars”
  • “Establish American leadership and a strategic presence on the Moon while expanding our U.S. global economic impact”
  • “Broaden our commercial and international partnerships”
  • “Inspire a new generation and encourage careers in STEM”

    learn more..

The missions needed to complete the Artemis program include awe-inspiring technical challenges. The different rockets, systems and other constructs needed to lay the foundation for further space exploration will be mankind’s biggest architectural accomplishment after the international space station.

SLS – Image Credit NASA

To simplify the technical story behind the Artemis program I will briefly mention the major constructs needed to complete the mission.

SLS
To launch the different missions for the program NASA will use the SLS or “Space Launch System” which will be the most powerful rocket NASA has ever built. The SLS will be able to carry a max capacity of approximately 26tons to the Moon.

Orion Spacecraft
On top of the SLS sits the Orion spacecraft which is the module astronauts will use to dock to the Lunar Gateway module. In Greek mythology Orion the hunter is the only one that could ever win Artemis’ heart. The capsule is equipped with abort systems and designed to offer safe re-entry from deep space return velocities

Lunar Gateway
The Lunar Gateway is the station in which astronauts will live and carry out experiments during their orbit around the Moon. The station must serve as an outpost between the earth and Moon to which visiting spacecraft can dock. It will hold living quarters and a science lab where astronauts can live up to 3 months at a time. The station will be much smaller than the ISS with an interior size of a studio apartment.

Reusable Moon Landers
To actually get the astronauts to the surface of the Moon NASA plans to build re-usable Moon landers. These landers should be able to complete multiple trips to different locations on the Moon. In between missions these landers can refuel at the Lunar Gateway while being prepared for new missions. Next to landers for the astronauts NASA has offered contracts to private companies for building Commercial Lunar Payload Services (CLPS). The companies involved will be responsible for delivering science and technology payloads to the Moons surface

Lunar Gateway – Image Credit NASA

All together I am really looking forward to seeing this mission unfold over the years. NASA has stated that the goal is to have people walk on the lunar surface by 2024. The programm will consist out of two major launches: Artemis 1 launches in 2020 with all components ready for testing, Artemis 2 should follow in 2024 and bring us back to the Moon.

Starhopper

Hop ’till you drop

This week SpaceX released footage of its second test-flight with “Starhopper”, their go-to vehicle for future Mars exploration. The “little” rocket suffered a rough start as heavy winds already toppled it over once, fire during pre-flight testing made SpaceX abort its first flight attempt. Since then, after the first small hop, the almost 20m tall spaceship completed its second test-flight during which it flew to a height of approximately 150 meters. SpaceX’s unique vehicle staggers audiences not because of its strange and bulgy looks but because of the unprecedented technological features it brings forth.

The Starhopper, unlike other SpaceX rockets and vehicles so-far, has been outfitted with the brand new “Raptor” engine. This liquid methane fueled, full flow staged combustion engine is not only very efficient but most importantly its fuel, liquid methane, is manufacturable on Mars. The red planet has a CO2 rich atmosphere which in combination with sub-surface water & water retrieved from polar ice can be made into methane fuel! In terms of efficiency SpaceX is again on top of the game. (further reading on the Raptor)

SpaceX’s liquid methane powered Raptor engine

Starhopper, for now, is the only vehicle to have been equipped with these Raptor engines but they are scheduled to be used in many other SpaceX endeavours. Next in line on the space conquering calendar is test flights for Starhopper’s bigger brothers Mk1 and Mk2. According to Musk, these orbital rockets are to be equipped with a minimum of 3 raptor engines. The Mk prototypes will subsequently lead us to the final goal, the production of Starship, Musk’s interplanetary people carrier. All together we can cheer for this successful test-flight as it brings us one step closer to the red planet!

Starhopper’s second test-flight compared to its first flight shows real potential as within 57 seconds it lifted itself up to 150 meters and safely landed on its feet in a cloud of dust. The first hop was not the visual spectacle the people had anticipated to see as the total undertaking happened within one gigantic cloud of dust and smoke, the second flight is a marvel to watch though.

Credits SpaceX

After witnessing this beauty of a manouvre I can’t wait to see what eye-candy the next prototypes with multiple Raptors will bring us. For now, I really enjoyed writing this article as being one of my first blogs for my new website. I am looking forward to covering much more space related subjects soon, so stay tuned!

How did our moon form?

Museum planetary science researcher Prof Sara Russell explains the origins of Earth’s closest companion.

” Analysis of samples brought back from the NASA Apollo missions suggest that the Earth and Moon are a result of a giant impact between an early proto-planet and an astronomical body called Theia. “

A FEW THEORIES

‘There used to be a number of theories about how the Moon was made and it was one of the aims of the Apollo program to figure out how we got to have our Moon,’ says Sara.

Prior to the Apollo mission research, there were three theories about how the Moon formed.

Capture theory suggests that the Moon was a wandering body (like an asteroid) that formed elsewhere in the solar system and was captured by Earth’s gravity as it passed nearby. In contrast, accretion theory suggested that the Moon was created along with Earth at its formation. Finally, according to the fission scenario, Earth had been spinning so fast that some material broke away and began to orbit the planet.

What is most widely accepted today is the giant-impact theory. It proposes that the Moon formed during a collision between the Earth and another small planet, about the size of Mars. The debris from this impact collected in an orbit around Earth to form the Moon.

Kerry Lotzaf – Natural History Museum 30-04-2018 > Full Article