How do I see the ISS from Earth? 

The International Space Station (ISS) is so large that it’s visible from Earth without a telescope!  The International Space Station is approximately 250 miles above the surface of the Earth in Low Earth Orbit. Traveling at approximately 17,500 miles per hour, the ISS circles the globe once every ninety minutes. 

ISS
Photo Credit: NASA

Why is the ISS moving across the sky? 

The ISS resides in Low Earth Orbit (LEO). Objects in LEO circle the globe. Objects in Geostationary Orbit (GEO) do not circle the globe and remain stationary above one location.

  • Satellites in Low Earth Orbit travel at approximately  4.85 miles per second (7.8 km per second) with an altitude of approximately 160 km to 1000 km above the earth. LEO satellites circle the globe sixteen times each day. The ISS is in LEO.
  • Satellites in Geostationary orbit travel approximately 2.26 miles per second (3.8 km per second) with an altitude of approximately 36,000 km above the earth. GEO satellites match the Earth’s rotation speed, appearing “stationary” above the Earth. 
Photo Credit: NASA

Where do I look? 

The ISS is in a constant state of motion. Atmospheric drag and Earth’s gravity create orbital altitude degradation on the ISS. Changes in the ISS’s altitude modify its trajectory. In theory, the exact orbit path will repeat every three days. 

A good way to determine when the ISS will be traveling near you is to use NASA Spot the Station website. Entry your city, and the website generates a list of upcoming passes near your location. Don’t worry if your exact city isn’t listed. Pick a city that’s close to you. 

DateVisibleMax Height*AppearsDisappears
Today, 5:30 AM5 min23°10° above S10° above ENE
Today, 4:44 PM2 min11°10° above SE10° above ESE
Tomorrow, 6:18 AM6 min29°10° above WSW10° above NNE

Here’s an example of a flyby chart from the NASA Spot the Station website based on your current location. 

International Space Station
Photo Credit: European Space Agency

Which direction should I look?

Take a few moments to orient yourself outdoors. Which direction is N, S, E, W?  

Old School: 

  1. Use a compass and orient yourself in the proper direction
  2. Use your hands to determine approximate viewing height
    1. Make a fist, knuckles rolled forward, and raise it to eye height
    2. The approximate distance from your thumb to your pinky finger is 10°
    3. Make the “hang loose” or “aloha” symbol with your hand. It’s 25° from your pinky to your thumb.
    4. Pay close attention to the ISS Max Height above the horizon. Landscapes or buildings can easily (easily) cover up to 15-20° of the horizon. 

New School: 

  1. Use your favorite cell phone app to orient yourself (N,S,E,W) 
  2. Use the app to find the ISS
  3. (-) cell phone brightness
Diagram Credit: NASA

There it is!

Now that you’re oriented and know where to look, it’s time to locate the ISS!  Be patient and relax.  Soon enough, you’ll see satellites, even if they’re not the ISS.

What’s a Starlink Satellite Train?

When viewing conditions are “correct,” it’s possible to see a string of satellites traversing the nighttime sky lined up in a row.   This unusual sight is known as a Satellite Train.

starlink satellite train
Photo Credit: Forest Katsch

The number of Low Earth Orbit (LEO) satellites launched is growing each year. The increased number of satellites in orbit has a direct impact on how we view our nighttime skies. Starlink has approximately 3,800 satellites circling the Earth.

Where are the satellites now?

Heavens-Above and Constellation Starlink have fantastic interactive 3D models. The sheer volume of Starlink Satellites is stunning. Select Live Map and locate the satellite train that’s closest to you on Findstarlink

Geostationary and Low Earth Orbiting Satellites

  • Geostationary (GEO) Satellites are 36,000 km above the Earth.
    • Slow upload/download times.  (High latency.)
  • LEO satellites are approximately 160 km to 1000 km above the Earth.
    • Fast upload/download times. (Low latency.)
view from a satellite
Photo Credit: NASA

What’s a Starlink Satellite?

A Starlink Satellite transmits internet signals from a satellite to a ground transceiver. The ground transceiver sends a signal to a router. The end user connects to the internet through the router. 

LEO satellites are constantly “on the move” as they circle the Earth.  This includes crossing over the oceans that cover 71% of the globe.

The best way to ensure global coverage is to place additional satellites into orbit. Each Starlink launch adds approximately 50-60 Starlink Satellites. Starlink is planning on weekly launches.

Who needs it?

Starlink plans to provide high-speed internet access to communities with poor internet service.  Poor service may be due to geographic location or lack of infrastructure.

space capsule
Photo Credit: Jeremy Straub

How Many?

Starlink is the first company to place satellites, in bulk (3,271), into LEO. Starlink currently has FCC approval for 12,000 satellites. Starlink’s projected build-out is closer to 42,000 satellites. A baseline expectation is 100,000 satellites in LEO, (all companies/nations combined) by 2030.

What’s a Starlink Satellite train?

Starlink satellites begin orbit at the approximate height of 350 km and move to an altitude of 550 km. They travel “in a row” as they orbit the Earth. The satellites are visible to the naked eye when they’re at a lower elevation.

A Starlink Satellite train is a row of Satellites traveling across the sky “in a row” or a “string of pearls.”

Astronomers express concern

Astronomers worry that the satellite trains will impact scientific research.  Papers are being published highlighting the satellite train’s negative impact on astronomy.

Astronomers are reflecting on the Kessler syndrome as a real possibility: A satellite breaks or shatters into smaller pieces. A second satellite files through the debris field. The second satellite breaks or shatters into smaller pieces.  Snowball effect.

starlink satellite
Photo Credit: Marek Piwnicki

Moving forward

Faster internet connections may be the beginning of an economic equalizer for less developed regions. Increasing the number of satellites in low earth orbit may cause considerable scientific angst. What’s the right answer?  

Galaxies- A Look Into the Stars

The science of astronomy has defined a galaxy as a system of stars, planets, dust, and other materials that revolve around a common center of mass. A galaxy can be very large and include billions of stars.

galaxy
Photo Credit: Bryan Goff

Many galaxies have names. The names are often based on the constellation or the location of the star. Some galaxies have more interesting names than others. Most of these are named by astronomers who discovered them.

Spiral Galaxies

Spiral galaxies are the brightest galaxies that are far away. They are made up of stars and planets that are rotating in the opposite direction to shape the galaxy. There are lots of colors in the material in these galaxies. Another type of galaxy is an elliptical galaxy. These galaxies are shaped like grains of rice.

Galaxies are grouped together based on their gravitational attraction. Many galaxies are also grouped into clusters. One of these groups is the Local Group of 54 galaxies. This group includes our own Milky Way galaxy. It consists of hundreds of billions of stars.

spiral galaxy
Photo Credit: NASA

Types of Galaxies

Most modern catalogs of galaxies contain thousands of objects. The New General Catalog of Principal Galaxies, for example, has over 73,000 objects in it. When a new catalog is published, most of the objects have catalog designations. For instance, the Whirlpool Galaxy is a Messier object. Another example is the Pinwheel Galaxy, which is located in the Coma Benerices constellation.

Galaxies can be classified into three basic types. These are barred spiral, barred elliptical, and elliptical. While most are categorized by their size, some are still grouped by their shape. In general, a galaxy is a collection of planets and stars, but can also be a system of nebulae and dust.

The names of galaxies can vary, depending on how the catalog is compiled. Some galaxies are not included because they do not show up as separate objects in the sky. Others are only part of larger galaxy clusters. An example is the Sagittarius Dwarf Spheroidal Galaxy, which is not listed because it is not seen as a separate galaxy.

There are also a number of unusually shaped galaxies. These include galaxies in the process of colliding, and galaxies with active nuclei. These objects are thought to be in a transitory phase of galactic development.

galaxies
Photo Credit: Greg Rakozy

Where Do Galaxies Get Their Names?

Several ancient cultures named ten thousand stars. However, there are only a few thousand that are bright enough for human observation with the naked eye. Using the names of stars and constellations is a great way to learn about outer space and the universe. You can also visit a planetarium to see displays of deep-space features.

Although it can be challenging to identify certain galaxies, the International Astronomical Union has produced several official catalogs. The New General Catalog of Nebulae and Star Clusters is the most widely used catalog. Other popular catalogs are the Atlas of Peculiar Galaxies, the Extragalactic Catalog, and the Markarian Catalog.

What Are the Origin of Mars’ Moons?

It’s always interesting to hypothesize about where various moons come from. In some cases, the creation of a moon is easy to determine, but with the origin of Mars’ moons, that is not the case. With some planets, it’s pretty obvious that a moon was formed due to an impact, such is believed to be the case with Earth’s moon, but what about its next-door neighbor, Mars? The origin of Mars’ moons don’t appear to come from this type of source, and there’s one main reason that astronomers theorize this: the composition of the moons.

origin of mars' moons
Photo Credit: Justin Cowart aquired by India’s Mars Orbiter Mission

What Are Mars’ Moons Made out of?

The composition of Mars’ moons put them in a category that astronomers call “C-Type asteroids”. These are the most common type of asteroids in the Solar System, making up for over 80% of all asteroids, especially those in the outer part of the asteroid belt. The “C” in the name stands for carbon and refers to the predominant material found throughout the moons surface.

Astronomers are far more certain about the material composition of the larger, innermost moon. This is for a few reasons, and not just because there is more surface area to explore. Stickney, the large crater, allows for the investigation of the fine dust and boulders that the impact left behind, which allows for the scientists to further conclude that this moon is very likely made up of a carbonaceous material.

Stickney crater
Photo Credit: NASA

It is a little more difficult to ascertain the material of the smaller, outermost moon. Due to its size, its gravitational pull is much, much weaker. This presents a problem. Typically, when small meteors hit the surface, surface material is thrown up and it returns down, creating the dusty and rocky features that make up the barren moons that you are used to seeing.

It is believed that this small moon’s gravity is so low that the ejected material simply doesn’t come back down, leaving its surface much smoother, but this makes it more troublesome to be certain that it is also the same carbonaceous material, though scientists are pretty sure that it is, based on the similarities to the other moon.

origin of Mars' moons
Photo Credit: NASA

Discovering the Origin of Mars’ Moons

The truth is that the origins of these moons still remain a debate among astronomers to this day. Many believe that, in some way, they originated in the nearby asteroid belt. The question is when they came to Mars’ side. Some astronomers believe that these moons came to the planet after it had formed and established its gravitational pull, dragging the asteroids out of the belt on their own. Others believe that the asteroids had already drifted out around the time that Mars was beginning to form and came along for the ride with Mars’ formation. The true origins still remain controversial.

Quick Facts About Mars’ Moons

Mars' Moons
Photo Credit: PlanetVolumes

Compared to Earth’s moon, Mars’ moons are a mere fraction in size. Unlike Earth’s moon, they cannot be seen by the naked eye in the night sky. If you wish to see them, you need to use a telescope and you need to have a good sense of where to be looking. This is because these moons are incredibly small.

The larger, innermost moon has a radius of just over 11 kilometers. The smaller, outermost moon is approximately half the size of the larger moon with a radius of approximately 6 kilometers. Compare both of these to Earth’s moon which has a radius of 1,736 kilometers, and you may see why Mars’ moons are so difficult to find in the night sky.

Mars' Moons
Photo Credit: NASA

Why are Mars’ Moons Such an Odd Shape?

One of the most notable aspects of these moons is the fact that they, very clearly, do not look the way that other moons do. One moon is a bit warped in shape, oblong and unnatural, while the other is strange and square-like. This is because the gravity on these moons is so low, due to their size and lack of mass, that they cannot pull their own material into a perfectly spherical shape the way that most other moons can. The larger, innermost moon ends up being somewhat oblong in shape, being likened to a potato. The smaller, outermost moon is closer to a square.

Phobos
Photo Credit: NASA
Demios
Photo Credit: NASA

An Imminent Problem

Another unique aspect of these moons is the fact that the larger moon is, in relative terms, quickly being drawn closer to Mars. It is a known fact that this moon is orbiting Mars only about 6,000 kilometers away, which is closer than any other moon orbits its planet. At a rate of approximately two meters per century, it only getting closer. While this may not seem like much at first, this is a noticeable speed in terms of planetary movement. This also means that in approximately 50 million years, this moon is going to collide with Mars, either breaking down entirely in a massive collision or breaking into smaller pieces and forming a ring.

What is the Coldest Place in the Universe?

We know that Uranus is the coldest planet in the Solar System, existing at a frigid minus 371 degrees Fahrenheit. Have you ever wondered what the coldest place in the universe is?

coldest place in the universe
Photo Credit: Tasos Mansour

It’s well-known that there is a lower temperature limit: absolute zero. At absolute zero (minus 459 degrees Fahrenheit), all of the atomic and subatomic particles stop moving. Temperature measures the kinetic energy of matter. Namely, temperature describes how fast the atomic and subatomic particles in matter are moving. The faster they move, the higher the temperature. When they completely stop moving, they have zero kinetic energy and have reached absolute zero.

If there is no matter, there is no temperature. Thus, a complete vacuum has no temperature. It is neither cold nor hot. Deep space is not a complete vacuum; it has a tiny amount of matter in it that was created and heated by the Big Bang. Space has a temperature of minus 455 degrees Fahrenheit, which is clearly above absolute zero.

Star
Photo Credit: NASA

Boomerang Nebula: The Coldest Place in the Universe

The coldest place in the universe that anyone has observed so far is the Boomerang Nebula, which is about 5000 light years away from the Earth. Part of the Boomerang Nebula is estimated to be a frigid minus 457 degrees Fahrenheit, actually cooler than deep space and barely above absolute zero. The Boomerang Nebula is believed to be a dying star system. The star is spraying solar winds carrying mass and starlight out into space, where it rapidly expands and the particles push against the particles present in deep space, transferring some of their kinetic energy and causing the area around the dying star to cool below the background temperature of deep space.

universe
Photo Credit: NASA

Thus, while Uranus may be the coldest planet in the Solar System, it is not the coldest place in the universe and it’s a lot warmer than deep space and significantly warmer than the Boomerang Nebula.