That's True With Stars. We Can Never See Stars Or Planets In The 'now' Bc It Took The Light We Are Seeing

Discovering the Universe Through the Constellation Orion

Do you ever look up at the night sky and get lost in the stars? Maybe while you’re stargazing, you spot some of your favorite constellations. But did you know there’s more to constellations than meets the eye? They’re not just a bunch of imaginary shapes made up of stars — constellations tell us stories about the universe from our perspective on Earth.

What is a constellation?

A constellation is a named pattern of stars that looks like a particular shape. Think of it like connecting the dots. If you join the dots — stars, in this case — and use your imagination, the picture would look like an object, animal, or person. For example, the ancient Greeks believed an arrangement of stars in the sky looked like a giant hunter with a sword attached to his belt, so they named it after a famous hunter in their mythology, Orion. It’s one of the most recognizable constellations in the night sky and can be seen around the world. The easiest way to find Orion is to go outside on a clear night and look for three bright stars close together in an almost-straight line. These three stars represent Orion's belt. Two brighter stars to the north mark his shoulders, and two more to the south represent his feet.

Credit: NASA/STScI

Over time, cultures around the world have had different names and numbers of constellations depending on what people thought they saw. Today, there are 88 officially recognized constellations. Though these constellations are generally based on what we can see with our unaided eyes, scientists have also invented unofficial constellations for objects that can only be seen in gamma rays, the highest-energy form of light.

Perspective is everything

The stars in constellations may look close to each other from our point of view here on Earth, but in space they might be really far apart. For example, Alnitak, the star at the left side of Orion's belt, is about 800 light-years away. Alnilam, the star in the middle of the belt, is about 1,300 light-years away. And Mintaka, the star at the right side of the belt, is about 900 light-years away. Yet they all appear from Earth to have the same brightness. Space is three-dimensional, so if you were looking at the stars that make up the constellation Orion from another part of our galaxy, you might see an entirely different pattern!

The superstars of Orion

Now that we know a little bit more about constellations, let’s talk about the supercool cosmic objects that form them – stars! Though over a dozen stars make up Orion, two take center stage. The red supergiant Betelgeuse (Orion's right shoulder) and blue supergiant Rigel (Orion's left foot) stand out as the brightest members in the constellation.

Credit: Derrick Lim

Betelgeuse is a young star by stellar standards, about 10 million years old, compared to our nearly 5 billion-year-old Sun. The star is so huge that if it replaced the Sun at the center of our solar system, it would extend past the main asteroid belt between Mars and Jupiter! But due to its giant mass, it leads a fast and furious life.

Betelgeuse is destined to end in a supernova blast. Scientists discovered a mysterious dimming of Betelgeuse in late 2019 caused by a traumatic outburst that some believed was a precursor to this cosmic event. Though we don’t know if this incident is directly related to an imminent supernova, there’s a tiny chance it might happen in your lifetime. But don't worry, Betelgeuse is about 550 light-years away, so this event wouldn't be dangerous to us – but it would be a spectacular sight.

Rigel is also a young star, estimated to be 8 million years old. Like Betelgeuse, Rigel is much larger and heavier than our Sun. Its surface is thousands of degrees hotter than Betelgeuse, though, making it shine blue-white rather than red. These colors are even noticeable from Earth. Although Rigel is farther from Earth than Betelgeuse (about 860 light-years away), it is intrinsically brighter than its companion, making it the brightest star in Orion and one of the brightest stars in the night sky.

Credit: Rogelio Bernal Andreo

Buckle up for Orion’s belt

Some dots that make up constellations are actually more than one star, but from a great distance they look like a single object. Remember Mintaka, the star at the far right side of Orion's belt? It is not just a single star, but actually five stars in a complex star system.

Credit: X-ray: NASA/CXC/GSFC/M. Corcoran et al.; Optical: Eckhard Slawik

Sword or a stellar nursery?

Below the three bright stars of Orion’s belt lies his sword, where you can find the famous Orion Nebula. The nebula is only 1,300 light-years away, making it the closest large star-forming region to Earth. Because of its brightness and prominent location just below Orion’s belt, you can actually spot the Orion Nebula from Earth! But with a pair of binoculars, you can get a much more detailed view of the stellar nursery. It’s best visible in January and looks like a fuzzy “star” in the middle of Orion’s sword.

More to discover in constellations

In addition to newborn stars, Orion also has some other awesome cosmic objects hanging around. Scientists have discovered exoplanets, or planets outside of our solar system, orbiting stars there. One of those planets is a giant gas world three times more massive than Jupiter. It’s estimated that on average there is at least one planet for every star in our galaxy. Just think of all the worlds you may be seeing when you look up at the night sky!

It’s also possible that the Orion Nebula might be home to a black hole, making it the closest known black hole to Earth. Though we may never detect it, because no light can escape black holes, making them invisible. However, space telescopes with special instruments can help find black holes. They can observe the behavior of material and stars that are very close to black holes, helping scientists find clues that can lead them closer to discovering some of these most bizarre and fascinating objects in the cosmos.

Next time you go stargazing, remember that there’s more to the constellations than meets the eye. Let them guide you to some of the most incredible and mysterious objects of the cosmos — young stars, brilliant nebulae, new worlds, star systems, and even galaxies!

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A small question:

Would anybody want me to do lessons? Like if you send in an ask like 'Hey, what do you know abt *science topic*?' I could do some research and make it a post with links and videos? (Like my Gravitational Waves in the Space-Time Continuum post [link below, and pinned to my acct])

Space Boii

Einstein's Theories of Relativity

Gravitational Waves in the Space-Time Continuum Einstein has two theories of relativity. The first is The Theory of Special Relativity (1905

Would anybody send in asks???

5 Out of this World Experiments Awaiting Crew-1 Space Scientists

NASA astronauts Shannon Walker, Victor Glover, and Mike Hopkins, and JAXA (Japan Aerospace Exploration Agency) astronaut Soichi Noguchi embark on a historic mission on November 14, 2020 aboard the Crew Dragon. NASA’s Crew-1 mission marks the first certified crew rotation flight to the International Space Station. During their 6-month stay on orbit, these crew members will don their science caps and complete experiments in microgravity.  Check out five out of this world experiments you can expect to see these space scientists working on during Expedition 64.

1. Space Gardening

The Crew-1 astronauts will become space farmers with the responsibility of tending to the rad(ish) garden located in a facility known as the Advanced Plant Habitat (APH). Researchers are investigating radishes in the Plant Habitat-02 experiment as a candidate crop for spaceflight applications to supplement food sources for astronauts. Radishes have the benefits of high nutritional content and quick growth rates, making these veggies an intriguing option for future space farmers on longer missions to the Moon or Mars.

2. Micro Miners

Microbes can seemingly do it all, including digging up the dirt (so to speak).  The BioAsteroid investigation looks at the ability of bacteria to break down rock.  Future space explorers could use this process for extracting elements from planetary surfaces and refining regolith, the type of soil found on the moon, into usable compounds.  To sum it up, these microbial miners rock.

3. Cooler Exploration Spacesuits

The iconic spacesuits used to walk on the moon and perform spacewalks on orbit are getting an upgrade. The next generation spacesuit, the Exploration Extravehicular Mobility Unit (xEMU), will be even cooler than before, both in looks and in terms of ability to regulate astronaut body temperature.  The Spacesuit Evaporation Rejection Flight Experiment (SERFE) experiment is a technology demonstration being performed on station to look at the efficiency of multiple components in the xEMU responsible for thermal regulation, evaporation processes, and preventing corrosion of the spacesuits.

4. Chips in Space

Crew-1 can expect to get a delivery of many types of chips during their mission.  We aren’t referring to the chips you would find in your pantry.  Rather, Tissue Chips in Space is an initiative sponsored by the National Institutes of Health to study 3D organ-like constructs on a small, compact devices in microgravity. Organ on a chip technology allows for the study of disease processes and potential therapeutics in a rapid manner. During Expedition 64, investigations utilizing organ on a chip technology will include studies on muscle loss, lung function, and the blood brain barrier – all on devices the size of a USB flashdrive.

5. The Rhythm of Life

Circadian rhythm, otherwise known as our “internal clock,” dictates our sleep-wake cycles and influences cognition. Fruit flies are hitching a ride to the space station as the subjects of the Genes in Space-7 experiment, created by a team of high school students.  These flies, more formally known as the Drosophila melanogaster, are a model organism, meaning that they are common subjects of scientific study. Understanding changes in the genetic material that influences circadian rhythm in microgravity can shed light on processes relevant to an astronaut’s brain function.

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SHIELDS Up! NASA Rocket to Survey Our Solar System’s Windshield Apr 16, 2021

Eleven billion miles away – more than four times the distance from us to Pluto – lies the boundary of our solar system’s magnetic bubble, the heliopause. Here the Sun’s magnetic field, stretching through space like an invisible cobweb, fizzles to nothing. Interstellar space begins. “It’s really the largest boundary of its kind we can study,” said Walt Harris, space physicist at the University of Arizona in Tucson.

We still know little about what lies beyond this boundary. Fortunately, bits of interstellar space can come to us, passing right through this border and making their way into the solar system.

A new NASA mission will study light from interstellar particles that have drifted into our solar system to learn about the closest reaches of interstellar space. The mission, called the Spatial Heterodyne Interferometric Emission Line Dynamics Spectrometer, or SHIELDS, will have its first opportunity to launch aboard a suborbital rocket from the White Sands Missile Range in New Mexico on April 19, 2021.

Our entire solar system is adrift in a cluster of clouds, an area cleared by ancient supernova blasts. Astronomers call this region the Local Bubble, an oblong plot of space about 300 light-years long within the spiraling Orion arm of our Milky Way galaxy. It contains hundreds of stars, including our own Sun.

We fare this interstellar sea is our trusty vessel, the heliosphere, a much smaller (though still gigantic) magnetic bubble blown up by the Sun. As we orbit the Sun, the solar system itself, encased in the heliosphere, hurtles through the Local Bubble at about 52,000 miles per hour (23 kilometers per second). Interstellar particles pelt the nose of our heliosphere like rain against a windshield.

Our heliosphere is more like a rubber raft than a wooden sailboat: Its surroundings mold its shape. It compresses at points of pressure, expands where it gives way. Exactly how and where our heliosphere’s lining deforms gives us clues about the nature of the interstellar space outside it. This boundary – and any deformities in it – are what Walt Harris, principal investigator for the SHIELDS mission, is after.

SHIELDS is a telescope that will launch aboard a sounding rocket, a small vehicle that flies to space for a few minutes of observing time before falling back to Earth. Harris’ team launched an earlier iteration of the telescope as part of the HYPE mission in 2014, and after modifying the design, they’re ready to launch again.

SHIELDS will measure light from a special population of hydrogen atoms originally from interstellar space. These atoms are neutral, with a balanced number of protons and electrons. Neutral atoms can cross magnetic field lines, so they seep through the heliopause and into our solar system nearly unfazed – but not completely.

The small effects of this boundary crossing are key to SHIELDS’s technique. Charged particles flow around the heliopause, forming a barrier. Neutral particles from interstellar space must pass through this gauntlet, which alters their paths. SHIELDS was designed to reconstruct the trajectories of the neutral particles to determine where they came from and what they saw along the way.

A few minutes after launch, SHIELDS will reach its peak altitude of about 186 miles (300 kilometers) from the ground, far above the absorbing effect of Earth’s atmosphere. Pointing its telescope towards the nose of the heliosphere, it will detect light from arriving hydrogen atoms. Measuring how that light’s wavelength stretches or contracts reveals the particles’ speed. All told, SHIELDS will produce a map to reconstruct the shape and varying density of matter at the heliopause.

The data, Harris hopes, will help answer tantalizing questions about what interstellar space is like.

For instance, astronomers think the Local Bubble as a whole is about 1/10th as dense as most of the rest of the galaxy’s main disk. But we don’t know the details – for instance, is matter in the Local Bubble is distributed evenly, or bunched up in dense pockets surrounded by nothingness? “There’s a lot of uncertainty about the fine structure of the interstellar medium – our maps are kind of crude,” Harris said. “We know the general outlines of these clouds, but we don’t know what’s happening inside them.”

Astronomers also don’t know much about the galaxy’s magnetic field. But it should leave a mark on our heliosphere that SHIELDS can detect, compressing the heliopause in a specific way based on its strength and orientation.

Finally, learning what our current plot of interstellar space is like could be a helpful guide for the (distant) future. Our solar system is just passing through our current patch of space. In some 50,000 years, we’ll be on our way out of the Local Bubble and on to who knows what.

“We don’t really know what that other cloud is like, and we don’t know what happens when you cross a boundary into that cloud,” Harris said. “There’s a lot of interest in understanding what we’re likely to experience as our solar system makes that transition.”

Not that our solar system hasn’t done it before. Over the last four billion years, Harris explains, Earth has passed through a variety of interstellar environments. It’s just that now we’re around, with the scientific tools to document it.

“We’re just trying to understand our place in the galaxy, and where we’re headed in the future,” Harris said.

TOP IMAGE….An illustration of the heliosphere being pelted with cosmic rays from outside our solar system. Credit: NASA’s Goddard Space Flight Center/Conceptual Image Lab

LOWER IMAGE….Illustration of the Local Bubble. Credits: NASA’s Goddard Space Flight Center

Decoding Nebulae

We can agree that nebulae are some of the most majestic-looking objects in the universe. But what are they exactly? Nebulae are giant clouds of gas and dust in space. They’re commonly associated with two parts of the life cycle of stars: First, they can be nurseries forming new baby stars. Second, expanding clouds of gas and dust can mark where stars have died.

Not all nebulae are alike, and their different appearances tell us what's happening around them. Since not all nebulae emit light of their own, there are different ways that the clouds of gas and dust reveal themselves. Some nebulae scatter the light of stars hiding in or near them. These are called reflection nebulae and are a bit like seeing a street lamp illuminate the fog around it.

In another type, called emission nebulae, stars heat up the clouds of gas, whose chemicals respond by glowing in different colors. Think of it like a neon sign hanging in a shop window!

Finally there are nebulae with dust so thick that we’re unable to see the visible light from young stars shine through it. These are called dark nebulae.

Our missions help us see nebulae and identify the different elements that oftentimes light them up.

The Hubble Space Telescope is able to observe the cosmos in multiple wavelengths of light, ranging from ultraviolet, visible, and near-infrared. Hubble peered at the iconic Eagle Nebula in visible and infrared light, revealing these grand spires of dust and countless stars within and around them.

The Chandra X-ray Observatory studies the universe in X-ray light! The spacecraft is helping scientists see features within nebulae that might otherwise be hidden by gas and dust when viewed in longer wavelengths like visible and infrared light. In the Crab Nebula, Chandra sees high-energy X-rays from a pulsar (a type of rapidly spinning neutron star, which is the crushed, city-sized core of a star that exploded as a supernova).

The James Webb Space Telescope will primarily observe the infrared universe. With Webb, scientists will peer deep into clouds of dust and gas to study how stars and planetary systems form.

The Spitzer Space Telescope studied the cosmos for over 16 years before retiring in 2020. With the help of its detectors, Spitzer revealed unknown materials hiding in nebulae — like oddly-shaped molecules and soot-like materials, which were found in the California Nebula.

Studying nebulae helps scientists understand the life cycle of stars. Did you know our Sun got its start in a stellar nursery? Over 4.5 billion years ago, some gas and dust in a nebula clumped together due to gravity, and a baby Sun was born. The process to form a baby star itself can take a million years or more!

After billions more years, our Sun will eventually puff into a huge red giant star before leaving behind a beautiful planetary nebula (so-called because astronomers looking through early telescopes thought they resembled planets), along with a small, dense object called a white dwarf that will cool down very slowly. In fact, we don’t think the universe is old enough yet for any white dwarfs to have cooled down completely.

Since the Sun will live so much longer than us, scientists can't observe its whole life cycle directly ... but they can study tons of other stars and nebulae at different phases of their lives and draw conclusions about where our Sun came from and where it's headed. While studying nebulae, we’re seeing the past, present, and future of our Sun and trillions of others like it in the cosmos.

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Our universe is FULL of strange and surprising things.

And luckily, our Hubble Space Telescope is there to be our window to the unimaginable! Hubble recently ran into an issue with its payload computer which controls and coordinates science instruments onboard the spacecraft. On July 16, teams successfully switched to backup hardware to compensate for the problem! A day later, the telescope resumed normal science operations. To celebrate, we’re taking you back to 2016 when our dear Hubble captured perhaps one of the most intriguing objects in our Milky Way galaxy: a massive star trapped inside a bubble! The star inside this Bubble Nebula burns a million times brighter than our Sun and produces powerful gaseous outflows that howl at more than four million miles per hour. Based on the rate the star is expending energy, scientists estimate in 10 to 20 million years it will explode as a supernova. And the bubble will succumb to a common fate: It’ll pop.

What kind of math is needed to get to Mars? How is the path of the lander calculated?

Dr. Beach’s Top 10 Beaches of 2021

For more than 30 years, Dr. Beach, aka Dr. Stephen Leatherman, has created an annual Top 10 Beach list. A professor and coastal geomorphologist at Florida International University, Dr. Beach factors in 50 different criteria including water color, sand softness, wave size, water temperature and more.

As we get ready to launch Landsat 9 this fall, we’re taking a tour of Dr. Beach’s Top 10 US beaches of 2021 as seen by Landsat 8.

10. Coast Guard Beach, Cape Cod, Massachusetts

Coast Guard Beach is located just north of the remote Nauset Inlet on Outer Cape Cod, Massachusetts. Except for the picturesque old white Coast Guard station that still sits atop the glacial bluffs, there is no development here; the best way to reach this beach is by bicycle from the Salt Pond Visitor’s Center or shuttle bus.

First mapped by Champlain in 1605, the shifting sands of this inlet are clearly visible in the Landsat image. This location is also at the point where the glacial sea cliffs transcend into a barrier beach (e.g., sand spit) that provides protection for the lagoon and development of lush salt marshes.

“In my early days as a Professor at Boston University and later at the University of Massachusetts at Amherst, I spent many summer and some winter-time days conducting scientific studies along this barrier beach.” – Dr. Beach

Landsat 8 collected this image of Coast Guard Beach on May 1, 2021.

9. Beachwalker Park, Kiawah Island, South Carolina

Beachwalker Park is a public beach located on the southern part of Kiawah Island, South Carolina. This barrier island in the Charleston area is 10-miles long and features a fine grained, hard-packed beach that can be traversed easily by bicycle.

This Landsat image shows a huge accumulation of sand as a series of shoals on the south end of the island, which can be reached from Beachwalker Park. These sandy shoals will eventually coalesce, becoming an extension of the sand spit that is the south end of Kiawah Island.

“In the early 2000s, I served as the beach consultant to the Town of Kiawah Island because their world-famous golf course on the north end was being threatened by severe erosion. It was necessary to artificially bypass some sand on the north end of the island so that the normal flow of sand along the island was reinstated, saving the outermost link of this PGA golf course.” – Dr. Beach

Landsat 8 collected this image of Beachwalker Park on April 9, 2021.

8. Coronado Beach, San Diego, California

Coronado Beach in San Diego is the toast of Southern California with some of the warmest and safest water on the Pacific coast. This 100-meter-wide beach is an oasis of subtropical vegetation, unique Mediterranean climate, and fine sparkling sand.

The harbor serves as a major port for the Navy’s Pacific fleet, the home port for several aircraft carriers. The docks and the crossing airplane runways for the Naval base are visible in this Landsat image.

“I really enjoy visiting this beautiful beach as well as having lunch and drinks, taking advantage of the hotel’s beachside service.” – Dr. Beach

Landsat 8 collected this image of Coronado Beach on April 23, 2020.

7. Caladesi Island State Park, Dunedin Clearwater, Florida

Caladesi Island State Park is located in the small town of Dunedin on the Southwest Florida coast. The stark white undeveloped beach is composed of crystalline quartz sand which is soft and cushy at the water’s edge, inviting one to take a dip in the sparkling clear waters.

While island is still in the Park’s name, Caladesi is no longer a true island as shown on the Landsat image--it is now connected to Clearwater Beach.

“Caladesi is located in the Tampa area, but it seems like a world away on this getaway island.” – Dr. Beach

Landsat 8 collected this image of Caladesi Island State Park on April 9, 2021.

6. Duke Kahanamoku Beach, Oahu, Hawaii

Duke Kahanamoku Beach is named for the famous native Hawaiian who was a big-board surfer and introduced surfing as a sport to mainland Americans and indeed the world.

One of the prominent features on this Landsat image is Diamondhead with its circular shape near the coast. This large cone of an extinct volcano provides the iconic backdrop for photos of Waikiki Beach.

“This is my favorite spot at the world-famous Waikiki Beach where you can both play in the surf and swim in the calm lagoonal waters.” – Dr. Beach

Landsat 8 collected this image of Duke Kahanamoku Beach on May 17, 2020.

5. Lighthouse Beach, Buxton, Outer Banks of North Carolina

Lighthouse Beach in the village of Buxton is located at Cape Hatteras, the most northern cape in the Outer Banks of North Carolina. This lifeguarded beach is the number one surfing spot on the US Atlantic Coast as the large offshore sand banks, known as Diamond Shoals, cause wave refraction focusing wave energy on this beach.

The Landsat image shows the seaward growth of south flank of Cape Hatteras as evidenced by the parallel lines of beach ridges.

“It is fun to walk down the narrow sand spit, more exposed at low tide, as waves are approaching from both directions because of the bending of the waves.” – Dr. Beach

Landsat 8 collected this image of Lighthouse Beach on May 3, 2020.

4. St. George Island State Park, Florida Panhandle

St. George Island State Park, located on the Florida panhandle and far from urban areas, is a favorite destination for beachgoers, anglers and bird watchers as nature abounds. Like other beaches on the panhandle, this long barrier island has a sugary fine, white sand beach.

In this Landsat image, St. George can be seen north of the bridge that links this barrier island to the mainland. The enclosed bay behind St. George Island is fairly shallow and the water much less clear as shown on the Landsat image, but it is not polluted.

“Besides swimming in the crystal-clear Gulf of Mexico waters, I enjoy beachcombing and shelling. While this island was hit hard in 2018 by Hurricane Michael, it has substantially recovered as there was little development to be impacted.” – Dr. Beach

Landsat 8 collected this image of St. George Island State Park on October 13, 2020.

3. Ocracoke Lifeguard Beach, Outer Banks of North Carolina

Ocracoke Lifeguarded Beach at the southern end of Cape Hatteras National Seashore was the first seashore to be incorporated into the National Park Service system.

The Landsat image shows Ocracoke to the north as separated by an inlet from Portsmouth Island. The village of Ocracoke was built at the wide area of the island where it was protected from oceanic waves during coastal storms which include both winter nor’easters and hurricanes.

“Ocracoke was once the home of the most infamous pirate Blackbeard and is still a very special place—my favorite getaway beach.” – Dr. Beach

Landsat 8 collected this image of Ocracoke Lifeguard Beach on May 3, 2020.

2. Cooper’s Beach, Southampton, New York

Cooper’s Beach in the tony town of Southampton on the south shore of Long Island, New York is shielded from the cold Labrador current, making for a fairly long summer swimming season. The white quartz sand is medium to coarse grained with some pebbles, making the beach slope fairly steeply into the water.

This Landsat image shows the fairly large coastal pond named Mecox Bay to the east with Shinnecock Inlet and Bay also displayed to the west. Coopers Beach is hundreds of yards wide, made of grainy white quartz sand and is backed by large sand dunes covered by American beach grass.

“I spent several decades conducting scientific studies of this very interest oceanic shoreline because it is so dynamic and the beachfront real estate so expensive. Some of the most gorgeous and expensive residential houses in the United States are located in the world-famous Hamptons.” – Dr. Beach

Landsat 8 collected this image of Coopers Beach on August 30, 2019.

1. Hapuna Beach State Park, Big Island Hawaii

Hapuna Beach State Park is a white coral sand beach that resides in a landscape dominated by dark brown lava flows on the Big Island of Hawaii. The crystal-clear water is perfect for swimming, snorkeling, and scuba diving during the summer months in contrast to winter big-wave days when pounding shorebreaks and rip currents make swimming impossible.

Hapuna and the other pocket beaches appear as an oasis in this otherwise fairly bleak landscape except for the areas irrigated as prominently shown on the Landsat imagery by the green vegetation.

“This volcanically active island is the only place that I know where you can snow ski at the high mountain tops and water ski in the warm ocean water on the same day.” – Dr. Beach

Landsat 8 collected this image of Hapuna State Park on January 5, 2021.

What’s your favorite beach?

View Dr. Beach’s 2021 picks and see Landsat views of these beaches over time.

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Hubble’s Guide to Viewing Deep Fields

They say a picture is worth a thousand words, but no images have left a greater impact on our understanding of the universe quite like the Hubble Space Telescope’s deep fields. Like time machines, these iconic images transport humanity billions of light-years back in time, offering a glimpse into the early universe and insight into galaxy evolution!

You’ve probably seen these images before, but what exactly do we see within them? Deep field images are basically core samples of our universe. By peering into a small portion of the night sky, we embark on a journey through space and time as thousands of galaxies appear before our very eyes.

So, how can a telescope the size of a school bus orbiting 340 miles above Earth uncover these mind-boggling galactic masterpieces? We’re here to break it down. Here’s Hubble’s step-by-step guide to viewing deep fields:

Step 1: Aim at the darkness

Believe it or not, capturing the light of a thousand galaxies actually begins in the dark. To observe extremely faint galaxies in the farthest corners of the cosmos, we need minimal light interference from nearby stars and other celestial objects. The key is to point Hubble’s camera at a dark patch of sky, away from the outer-edge glow of our own galaxy and removed from the path of our planet, the Sun, or the Moon. This “empty” black canvas of space will eventually transform into a stunning cosmic mosaic of galaxies.

The first deep field image was captured in 1995. In order to see far beyond nearby galaxies, Hubble’s camera focused on a relatively empty patch of sky within the constellation Ursa Major. The results were this step-shaped image, an extraordinary display of nearly 3,000 galaxies spread across billions of light-years, featuring some of the earliest galaxies to emerge shortly after the big bang.

Step 2: Take it all in

The universe is vast, and peering back billions of years takes time. Compared to Hubble’s typical exposure time of a few hours, deep fields can require hundreds of hours of exposure over several days. Patience is key. Capturing and combining several separate exposures allows astronomers to assemble a comprehensive core slice of our universe, providing key information about galaxy formation and evolution. Plus, by combining exposures from different wavelengths of light, astronomers are able to better understand galaxy distances, ages, and compositions.

The Hubble Ultra Deep Field is the deepest visible-light portrait of our universe. This astonishing display of nearly 10,000 galaxies was imaged over the course of 400 Hubble orbits around Earth, with a total of 800 exposures captured over 11.3 days.

Step 3: Go beyond what’s visible

The ability to see across billions of light-years and observe the farthest known galaxies in our universe requires access to wavelengths beyond those visible to the human eye. The universe is expanding and light from distant galaxies is stretched far across space, taking a long time to reach us here on Earth. This  phenomenon, known as “redshift,” causes longer wavelengths of light to appear redder the farther they have to travel through space. Far enough away, and the wavelengths will be stretched into infrared light. This is where Hubble’s infrared vision comes in handy. Infrared light allows us to observe light from some of the earliest galaxies in our universe and better understand the history of galaxy formation over time.

In 2009, Hubble observed the Ultra Deep Field in the infrared. Using the Near Infrared Camera and Multi-Object Spectrometer, astronomers gathered one of the deepest core samples of our universe and captured some of the most distant galaxies ever observed.

Step 4: Use your time machine

Apart from their remarkable beauty and impressive imagery, deep field images are packed with information, offering astronomers a cosmic history lesson billions of years back in time within a single portrait. Since light from distant galaxies takes time to reach us, these images allow astronomers to travel through time and observe these galaxies as they appear at various stages in their development. By observing Hubble’s deep field images, we can begin to discover the questions we’ve yet to ask about our universe.

Credit: NASA, ESA, R. Bouwens and G. Illingworth (University of California, Santa Cruz)

Hubble’s deep field images observe galaxies that emerged as far back as the big bang. This image of the Hubble Ultra Deep Field showcases 28 of over 500 early galaxies from when the universe was less than one billion years old. The light from these galaxies represent different stages in their evolution as their light travels through space to reach us.

Step 5: Expand the cosmic frontier

Hubble’s deep fields have opened a window to a small portion of our vast universe, and future space missions will take this deep field legacy even further. With advancements in technologies and scientific instruments, we will soon have the ability to further uncover the unimaginable.

Slated for launch in late 2021, NASA’s James Webb Space Telescope will offer a new lens to our universe with its impressive infrared capabilities. Relying largely on the telescope’s mid-infrared instrument, Webb will further study portions of the Hubble deep field images in greater detail, pushing the boundaries of the cosmic frontier even further.

And there you have it, Hubble’s guide to unlocking the secrets of the cosmos! To this day, deep field images remain fundamental building blocks for studying galaxy formation and deepening not only our understanding of the universe, but our place within it as well.

Still curious about Hubble Deep Fields? Explore more and follow along on Twitter, Facebook, and Instagram with #DeepFieldWeek!

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