The largest celestial bodies ranging from the planets to the stars, solar systems, galaxies, galactic clusters, and superclusters.

As an illustration, available data suggests that the Earth (measuring over 40, 000km across) is only about 0.12 pixels as seen from space! Indeed the cosmos is so vast that only by numbers can we attempt to comprehend its magnificence.

The Largest Planet in the Universe

Earth is our home planet and by now and through scientific knowledge, we know that life does not revolve around earth alone. Earth has a diameter of roughly 12, 756 km. It is one of the eight planets in our Solar System.

Speaking of which, the largest planet in our Solar System is Jupiter with a radius of 69,911km (or diameter of 139, 822 km). However, the largest known planet in the Universe is an exoplanet (planet outside our Solar System) called ROXs 42Bb. It is roughly 2.5x the size of Jupiter.

The Largest Star in the Universe 

The Sun is one of the most recognizable and familiar stars that can be seen from earth. It appears bigger only because it is closer. It is by no means the biggest star, not even in our local Solar System, even though it can contain 1 million Earths.

The biggest star in the Universe would be either the Stephenson 2-18 or the UY-Scuti. The former is being contested leaving the UY-Scuti as the next best option. To put it in perspective, it has a radius 1,700 times larger than that of the Sun or a volume large enough to swallow 5 billion Suns.

The Largest Solar System in the Universe 

Our Solar System comprises the Sun (also a star) at its center, eight planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune) orbiting around it, 146 moons, comets, asteroids and space rocks, ice, and dwarf planets such as Pluto.

Other than this, there are countless other solar systems in existence scattered across the vast cosmos. So, which is the largest solar system of them all? That would be the 2MASS J2126-840. Its orbit is said to be 140x that of Pluto’s.

The Largest Galaxy in the Universe

A galaxy typically comprises a huge collection of gas, dust, and billions of stars along with their respective solar systems, all bound together by gravity. The galaxy to which we belong is called the Milky Way. It is a spiral galaxy with more than 100 billion stars.

And no, that’s not the biggest galaxy in the universe. That title belongs to Alcyoneus. This gigantic galaxy’s diameter is 16.3 million light-years across! This means that at a speed of approximately 3 x 10⁸m/s, it’ll still take light 16.3 million years to travel across it.

The Largest Galaxy Cluster in the Universe

A galactic cluster is a group of gravitationally bound galaxies that come together to form a cluster. Now, imagine that a 6-million light-years-long galaxy like the IC 1011 combines with other gigantic galaxies to form a cluster!

It gets even bigger considering that some galaxy clusters can have hundreds and thousands of galaxies. The Local Group to which our Milky Way belongs, has a diameter of 1, 000, 000, 000, 000, 000, 000 km. But the largest known galaxy cluster is El Gordio.

The Largest Galaxy Supercluster in the Universe

And just when you thought you’ve seen it all, it gets much bigger as the Universe shows off its Superclusters. As the name suggests, these are clusters of galaxy clusters. These clusters of galactic clusters are simply humongous in size.

Our own supercluster is the Laniakea Supercluster, home to around 100, 000 galaxies. However, it pales in comparison to the Hercules-Corona Borealis Great Wall, the largest known single entity in the Universe. This Supercluster is 10 billion light-years across.

The Largest Object in the Universe

As far as the Universe is concerned, the only single entity bigger than the Hercules-Corona Borealis Great Wall supercluster is the Universe itself! As tremendous as this galactic supercluster is, it still doesn’t come close to the known Universe.

The known Universe is believed to be 13.7 billion years old and is said to span across more than 93 billion light years of space. This does not account for the yet unknown universe, nor the probable multiverse. The Universe is simply put, mind-boggling.

To say that these numbers are out of this world would be putting it mildly. The universe is extremely vast and there are no words to quantify it, only numbers will do.

Galaxies are important building blocks of the Universe as we know it. Whether you know little or nada about galaxies, we’re here to help. This post will highlight 10 fun facts about galaxies that you probably didn’t know.

The Universe is home to numerous celestial bodies that are strategically distributed throughout space. Including planets, planetary systems, suns, moons, solar systems, and of course, galaxies, among others.

Fun Fact #1: Galaxies are Almost as Old as the Universe

If you’ve ever wondered how old galaxies are, here’s the answer. Galaxies are believed to be anywhere around 13.5 billion years. They are believed to have started forming a few hundred million years after the Big Bang which occurred 13.7 billion years ago.

Fun Fact #2: Galaxies Used to Be Known as Island Universes

Philosopher, Immanuel Kant theorized that other galaxies (known as island universes) existed outside the Milky Way. Astronomers like Harlow Shapley argued otherwise. However, in the 1920s, Edwin Hubble was able to establish their existence, calling them “extragalactic nebulae.” 

Fun Fact 3#: Galaxies Comprise of Dust, Gas, and Matter

Galaxies typically consist of gas, interplanetary dust, stars, and their solar systems (including their moons, dwarf planets, asteroids, meteoroids, Kuiper belt objects, and comets, etc). All of these are gravitationally bound together.

Fun Fact #4: There are 4 Major Types of Galaxies

Galaxies come in different forms, shapes, and sizes. This has given rise to a system of classification for easy reference. The first type of galaxy is the spiral galaxy. Others include elliptical galaxies, peculiar galaxies, and irregular galaxies. 

Fun Fact #5: Our Galaxy Goes By Different Names

Our galaxy, a.k.a the Galaxy, is generally known as the Milky Way. However, that’s not its only nomenclature. It is also known as the “Silver River” in China. In the Kalahari Desert in southern Africa, it is referred to as the “Backbone of Night.”  

Fun Fact #6: Why Our Galaxy is Called the Milky Way

Our star, the Sun, is one of the billions of stars swirling in the Milky Way. It is described this way due to its appearance when viewed from earth. There’s also a Greek myth about the goddess, Hera, spraying milk across the sky.

Fun Fact #7: Galaxies are Gigantic 

Humongous doesn’t even begin to describe how monumental galaxies can be. For instance, the largest known galaxy, Alcyoneus, has a diameter of 16.3 million light-years, that’s nearly 3x the nearest contender, the IC 1011 with a diameter of 6 million light-years. 

Fun Fact #8: Galaxies are Numerous

From assuming that the Milky Way was the only galaxy, we now know that there are in fact, billions of galaxies out there. Each of these galaxies also contains numerous stars. For instance, the largest galaxy contains 100 trillion stars.  

Fun Fact #9: You Can See Some Galaxies With the Naked Eyes

Yes, you can view up to two galaxies with unaided eyes. These are our own Milky Way and the Andromeda galaxy. Although you won’t be able to view it in full, you can still see parts of them in a clear night sky.

Fun Fact #10: This is the Loneliest Galaxy in the Universe

Galaxies typically exist in groups or clusters. Each cluster can accommodate 100 to 1, 000 galaxies. These are also much larger superclusters, as well as superclusters of superclusters. But the NGC 503 is an exception. It holds the title of the world’s loneliest galaxy!

Now That You Know

Now that you know more fun facts about galaxies, we invite you to explore more about galaxies vs the universe. This will help to broaden your knowledge about how galaxies and the universe relate and function.

The next generation of planetary exploration kicks off in 2027 when NASA launches the Dragonfly Mission to Titan. Saturn’s moon Titan is the second-largest moon in the solar system.  Clouds, rain (methane), a nitrogen-based atmosphere, and weather patterns similar to Earth have scientists buzzing with excitement. 

Huygen’s Mission-2004

The Huygen probe landed on Titan in 2005 and broadcast data for 72 minutes.  Huygen captured atmospheric data as it descended through the haze and clouds.  Following the touchdown, Huygen captured and transmitted 100 pictures before the batteries ran out of power.  

The pictures and atmospheric data justified a return trip to Titan.  

The Four Phases of the Dragonfly Mission

1. Launch: Leaving Florida in 2027. The launch vehicle hasn’t been announced yet.
2. Cruise:
   • Starts when Dragonfly separates from the launch vehicle.  
   • Ends prior to Dragonfly entering Titan’s atmosphere
3. Entry, descent, landing (EDL).
   • Starts when Dragonfly is 789 miles (1,270 km) above Titan
   • Ends when Dragonfly touches down in a dune near the equator
4. Titan operation/science mission

Dragonfly Structure

The spacecraft has two components.

• Cruise stage-Located at the “top” of the spacecraft.  The cruise stage component separates from the Entry Vehicle at a specified height during atmospheric entry.  The cruise stage components will burn up, similar to how a rocket stage burns up upon reentry through Earth’s atmosphere.
  • The Cruise stage has three components.
    1. Earth Communications
    2. Propulsion
    3. Thermal control
• Entry Vehicle-three components
  • Backshell-Top component
    1. Parachute 
    2. Low gain antenna
    3. Separation systems
  • Rotorcraft lander-Middle component, protected by the Backshell above it and the heatshield below it.  
  • Heatshield-Protects the Rotorcraft lander during atmospheric entry.

Dragonfly in the Air

The Dragonfly weighs approximately 926 pounds (420 kg).  Instead of resting on wheels like previous NASA rovers, Dragonfly will rest on skids, just like a helicopter.  Lift is created via eight 53-inch (1.34 m) counter-rotating rotors.  

Landing

When the EDL is 0.75 miles (1.2 km) above Titan’s surface, the rotorcraft unit will detach from the Backshell and land itself.  Titan’s atmosphere is four times heavier than Earth’s.  Titan’s gravity is one-seventh of Earth’s gravity.  Combined, they create a perfect environment for low-power drone flights.

Surface Mobility 

The “relocatable lander” will fly to different locations during its 37-month ground mission.  The Dragonfly can fly for 30 minutes before recharging is required for the rotor motors.  The Dragonfly travels at a maximal speed of 22mph (33 kph).  Mar rover speeds max out a .1 mph (4,828 meters per hour).  

Data Analysis

Dragonfly has a plethora of hardware to analyze its surroundings.

• Mass Spectrometer: Elemental analysis
• Drills for Regolith samples from the surface and near the surface for analysis
• Gamma-Ray Neutron Spectrometer-Analysis of surface composition near the skids.
• Seismometer-Detect and measure ground movement
• Two LiDAR navigation sensors-realtime navigation sensors
• Ten Cameras to capture images! Close-up, panoramics, mosaic. 
• Optical navigation based on Cassini’s maps created from 127 flybys

Wrap Up

The Dragonfly will explore the chemistry of geographically different environments on the surface of Titan.  The elements, compounds, atmosphere, ocean, and seismic analysis are a window into Earth 3.5 billion years ago.  

Our fingers are crossed that Dragonfly will provide answers concerning whether Titan was once home to life.

Few moons create excitement like Enceladus! The ice-covered moon is the most reflective object in the solar system. Cassini flybys turned planetary science on its head! The data analysis is ongoing nearly a decade after Cassini left Enceladus.  

Gravitational Flexing

The interior core of Enceladus increases in temperature as the moon responds to the gravitational forces of Saturn.  

• Enceladus is tidally locked.
• One side of the moon always faces Saturn
  • Highest gravitational forces from Saturn
• One side of the moon faces away from Saturn
  • Lower gravitational forces from Saturn
• Gravitational intensity changes during orbit
• The different gravitational forces create friction, which creates heat.

South Pole

Fissures

The south pole has large crust fractures. Cassini detected approximately 101 geysers located within the fractures. The geysers are ejecting “something fluid” hundreds of miles into space at about 800 miles per hour (1287 km per hour). A portion of the plume falls back to the surface of Enceladus. The other part enters into orbit around Saturn in the E-Ring.

Temperature 

Scientists expected Enceladus’s surface temperature to be approximately -315℉ (-192℃). Roughly 80% of the sunlight is reflected from Enceladus. Scientists expected the poles to be colder than the Equatorial temperature. 

Infrared spectrometer data of the entire south pole shocked the scientists with an average temperature of -304℉ (151℃). Data subsets are much warmer at -261℉ (-163℃). Why are the temperatures so much different than expected?

The crust is thinner

Doppler data analysis reveals that the average crust/ice shell thickness is between 11 and 14 miles (18 to 22 km). The South Poles’ crust/ice shell thickness is much closer to 3 miles (5 km). Scientists believe that there’s an ocean underneath the south pole!

Plumes

Scientists couldn’t perform ground-level testing of the ocean inside Enceladus, but they could analyze the ejected matter from the underwater sea. Cassini flew through the plume of vapor seven times over a decade.

• Mass spectrometer data analysis reveals that the vapor plume contains methane, ammonia, nitrogen-bearing organic compounds, oxygen, and carbon.  
• Liquid water and rock interact at temperatures greater than 200℉ (90℃) and create Silica Nanograins. Silica nanograins equal hydrothermal activity. 
• Hydrothermal sites in the earth’s oceans contain organisms like tubeworms and crabs.

Mission time!

NASA relies on the scientific community to define and prioritize scientific questions. Once per decade, the National Academy of Science (NAS) generates recommendations for NASA. 

Two thousand four hundred members, including 190 Nobel prize winners, create recommendations for NASA. 

In 2022 the NAS recommended that NASA develops the Enceladus Orilander. The projected launch date is 2038, landing on Enceladus’s surface in 2050.  

The planned mission will orbit for 18 months and then collect data on the surface for 24 months. Plume data will be collected and analyzed: 

1.  Inside the E-Ring 
2. On the surface as the plume drops material onto the Orilander.
3. Below the surface with plume content that’s “dug up” with a probe.

Wrap up!

Enceladus is exciting! The building blocks of life might all be ready for discovery in an ocean buried under ice.   

An Overview of the Conditions on Venus

The physical environment on Venus is so horrific that humans can’t visit. Sulfuric rain, high temperatures, and crushing pressure do not equal a good place to visit. 

Galileo observed the size and shape of Venus change over several months as it circled the sun. Watching through his telescope in 1610 Galileo discovered that Venus was a planet and not a star.  Venus is discernible with the naked eye. The earliest humans that walked the Earth looked to the night skies and saw Venus.

Venus Firsts

• Mariner 2: Venus is the first planet visited by a spacecraft.  Mariner 2 passed within 21,607 miles (34,773 km) of the planet on December 14, 1962.  Mariner 2’s final data broadcast was on January 3rd, 1963.  Today Mariner 2 orbits the sun.
• Venera 4 descent module transmitted atmospheric data in 1967
• Venera 7 landed on the planet in 1970 and transmitted data for 23 minutes.
• Mariner 10: Ultraviolet (UV) images captured for the first time.
• Verena 9/10: Captured first black and white images on the surface of Venus.  Spacecraft survived for one hour.
• Verena 11/12: 1978 Spacecraft transmitted data for two hours.
• Venera 13/14: Transmission color images of the surface of Venus.
• 1980s-1990s: Radar mapping of the planet.
• Present: The Akatsuki is studying the chemistry and physics of the atmosphere. 
• Future: Three new missions will begin within the next decade.
• DAVINCI: Orbiter and Probe (2029)
• VERITAS: Orbiter (2031)
• EnVision: Orbiter (2032)

Why hasn’t there been more exploration of Venus?

Venus is closer to Earth (24 million miles/38 million km) than Mars (34 million miles/54.5 km).  So why hasn’t there been more exploration of Venus? 

Even though Venus is our closest next-door neighbor, she isn’t very friendly!

	Mars	Venus
Temp Low	-225°F/-123°C	719°F/655 °C
Temp High	70°F/20°C	864°F/462 °C
Pressure (bar)	0.016518	92
Clouds	Ice Crystals	Sulfuric Acid
Wind	20mph/32kph	224mph/360kph

Reasons to Not Visit Venus

1. The temperature is hot enough to melt Lead, Zinc, and Aluminum.  
2. The pressure on the surface of Venus will kill humans very quickly.
   1. Good news! You’ll last about five seconds due to the pressure.
   2. Bad news! The surface temperatures will kill you in roughly one second.
3. The pressure on the surface will collapse your spacecraft. You’ll need a spaceship akin to a submarine that can handle enormous pressures.  (Plus, there’s still that pesky temperature to deal with!)
4. The clouds on Venus contain Sulfuric Acid. 
5. There are wind storms on Mars, but Mars has a shallow atmospheric pressure. Venus’s thick atmosphere creates very intense windstorms

Why Should We Explore Venus?

Venus is Earth’s closest neighbor.  Scientists believe that billions of years ago, Venus was very much like Earth.  Venus is called Earth’s “twin” due to their similarities.

Examination of Venus’s formation process allows comparison between planets.  Venus ended up as a hellish planet, yet Earth ended up as a planet filled with life.  What made the difference between the two planets?

The Martian eXploration mission (MMX) will launch late in 2024. MMX will arrive at Mars approximately one year later. MMX will land on one of Mar’s moons and collect scientific data before returning to Earth in 2029.  

Scientists have long debated the origin of Mar’s two moons, Phobos and Deimos. Are the moons asteroids from Jupiter’s asteroid belt? Do the moons have the same elemental composition as Mars? 

Martian Moons Mission Timeline

• 2024: In November, Japan’s Aerospace Exploration Agency (JAXA) will launch the MMX from the Tanegashima Space Center in Japan.
• 2025: The spacecraft will arrive at Mars in September
• 2026-2028: The spacecraft will travel along a low-level retrograde ellipse path in a quasi-satellite orbit around Phobos.  

1. Phase 1: Preliminary Phobos data collection and instrument verification
2. Phase 2: Landing site selection based on data collection 
3. Phase 3: Phobos landing(s)
   1. Exploration module
   2. Rover delivery
4. Phase 4: Rover and xxx data collection of Phobos and Mars
5. Phase 5: Data collection of Deimos and Mars as MMX leaves Mars to return to Earth.
   1. The Mars orbit escape (MOE) will execute three maneuvers to move the spacecraft into an interplanetary trajectory toward Earth.
   2. The Exploration module may be jettisoned and left in Mars orbit. 

• 2029: In June, the MMX returns to Earth orbit
  • A capsule containing the regolith samples is ejected, passes through the atmosphere, and floats to the ground via a parachute. 
  • The spacecraft will deorbit and land in Australia.

MMX Rover

Dimensions

A small rover 16 x 15 x 12 inches (41 x 37 x 30 cm) weighing 55 lbs (25 kg) is “released” from the MMX Mothership when it’s approximately 131 feet (40m) above Phobos. The rover will passively land on the moon. The rovers’ expedition will last about 100 days.

Mobility Hardware

• Four arms will automatically adjust for the rover’s proper orientation. 
• Wheels move the rover at a rate of .8 inches (20mm) per second.
• NAVCAM-Natigation and imaging. 
• WheelCAM-Watching wheel interaction with the regolith.

Scientific Hardware

The rover will analyze the data before the MMX Mothership lands on the moon to verify that the preselected landing site is acceptable.  

• Surface Terrain-Is it safe for the Mothership to land?
• Grain size of the Regolith.  Is the ground so loose that the Mothership would sink?
• Mineralogical composition- What is the elemental composition of the ground? 
• Thermal properties-How warm is the ground?

MMX Mothership

The mothership will touch down on the moon’s surface at least once, possibly twice. The purpose of the touchdown is to collect > 10 g of the moon’s surface via sampling systems located in the landing legs.

The spacecraft will depart Phobos and collect data about Deimos. The material sample from Phobos will be analyzed on Earth. 

What Do Scientists Hope to Learn?

Scientists want to learn if Phobos and Demios have elemental compositions of asteroids or from the planet Mars. This will aid in understanding the evolution of our solar system’s planets.

Landing the MMX Mothership on Phobos provides insight into satellite and moon exploration.