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Why are we studying them? What’s purpose of this field for us on earth?

5 of Your Fermi Gamma-ray Space Telescope Questions Answered

The Fermi Gamma-ray Space Telescope is a satellite in low-Earth orbit that detects gamma rays from exotic objects like black holes, neutron stars and fast-moving jets of hot gas. For 11 years Fermi has seen some of the highest-energy bursts of light in the universe and is helping scientists understand where gamma rays come from.

Confused? Don’t be! We get a ton of questions about Fermi and figured we'd take a moment to answer a few of them here.

1. Who was this Fermi guy?

The Fermi telescope was named after Enrico Fermi in recognition of his work on how the tiny particles in space become accelerated by cosmic objects, which is crucial to understanding many of the objects that his namesake satellite studies.

Enrico Fermi was an Italian physicist and Nobel Prize winner (in 1938) who immigrated to the United States to be a professor of physics at Columbia University, later moving to the University of Chicago.

Original image courtesy Argonne National Laboratory

Over the course of his career, Fermi was involved in many scientific endeavors, including the Manhattan Project, quantum theory and nuclear and particle physics. He even engineered the first-ever atomic reactor in an abandoned squash court (squash is the older, English kind of racquetball) at the University of Chicago.

There are a number of other things named after Fermi, too: Fermilab, the Enrico Fermi Nuclear Generating Station, the Enrico Fermi Institute and more. (He’s kind of a big deal in the physics world.)

Fermi even had something to say about aliens! One day at lunch with his buddies, he wondered if extraterrestrial life existed outside our solar system, and if it did, why haven't we seen it yet? His short conversation with friends sparked decades of research into this idea and has become known as the Fermi Paradox — given the vastness of the universe, there is a high probability that alien civilizations exist out there, so they should have visited us by now.  

2. So, does the Fermi telescope look for extraterrestrial life?

No. Although both are named after Enrico Fermi, the Fermi telescope and the Fermi Paradox have nothing to do with one another.

Fermi does not look for aliens, extraterrestrial life or anything of the sort! If aliens were to come our way, Fermi would be no help in identifying them, and they might just slip right under Fermi’s nose. Unless, of course, those alien spacecraft were powered by processes that left behind traces of gamma rays.

Fermi detects gamma rays, the highest-energy form of light, which are often produced by events so far away the light can take billions of years to reach Earth. The satellite sees pulsars, active galaxies powered by supermassive black holes and the remnants of exploding stars. These are not your everyday stars, but the heavyweights of the universe. 

3. Does the telescope shoot gamma rays?

No. Fermi DETECTS gamma rays using its two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM).

The LAT sees about one-fifth of the sky at a time and records gamma rays that are millions of times more energetic than visible light. The GBM detects lower-energy emissions, which has helped it identify more than 2,000 gamma-ray bursts – energetic explosions in galaxies extremely far away.

The highest-energy gamma ray from a gamma-ray burst was detected by Fermi’s LAT, and traveled 3.8 billion light-years to reach us from the constellation Leo.

4. Will gamma rays turn me into a superhero?

Nope. In movies and comic books, the hero has a tragic backstory and a brush with death, only to rise out of some radioactive accident stronger and more powerful than before. In reality, that much radiation would be lethal.

In fact, as a form of radiation, gamma rays are dangerous for living cells. If you were hit with a huge amount of gamma radiation, it could be deadly — it certainly wouldn’t be the beginning of your superhero career.

5. That sounds bad…does that mean if a gamma-ray burst hit Earth, it would wipe out the planet and destroy us all?

Thankfully, our lovely planet has an amazing protector from gamma radiation: an atmosphere. That is why the Fermi telescope is in orbit; it’s easier to detect gamma rays in space!

Gamma-ray bursts are so far away that they pose no threat to Earth. Fermi sees gamma-ray bursts because the flash of gamma rays they release briefly outshines their entire home galaxies, and can sometimes outshine everything in the gamma-ray sky.

If a habitable planet were too close to one of these explosions, it is possible that the jet emerging from the explosion could wipe out all life on that planet. However, the probability is extremely low that a gamma-ray burst would happen close enough to Earth to cause harm. These events tend to occur in very distant galaxies, so we’re well out of reach.

We hope that this has helped to clear up a few misconceptions about the Fermi Gamma-ray Space Telescope. It’s a fantastic satellite, studying the craziest extragalactic events and looking for clues to unravel the mysteries of our universe!

Now that you know the basics, you probably want to learn more! Follow the Fermi Gamma-ray Space Telescope on Twitter (@NASAFermi) or Facebook (@nasafermi), and check out more awesome stuff on our Fermi webpage.

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Two are Better Than One: The NASA Twins Study

What exactly happens to the human body during spaceflight? The Twins Study,  a 340-day investigation conducted by NASA’s Human Research Program , sought to find answers. Scientists had an opportunity to see how conditions on the International Space Station translated to changes in gene expression by comparing identical twin astronauts: Scott Kelly who spent close to a year in space and Mark Kelly who remained on Earth.

The Process

From high above the skies, for almost a year, astronaut Scott Kelly periodically collected his own blood specimens for researchers on the ground during his One-Year Mission aboard the Space Station. These biological specimens made their way down to Earth onboard two separate SpaceX Dragon vehicles. A little bit of Scott returned to Earth each time and was studied by scientists across the United States.

Totaling 183 samples from Scott and his brother, Mark, these vials helped scientists understand the changes Scott’s body underwent while spending a prolonged stay in low Earth orbit.  

The Twins

Because identical twins share the same genetic makeup, they are very similar on a molecular level. Twin studies provide a way for scientists to explore how our health is impacted by the environment around us.

What We Learned: Gene Expression

A significant finding is the variability in gene expression, which reflects how a body reacts to its environment and will help inform how gene expression is related to health risks associated with spaceflight. While in space, researchers observed changes in the expression of Scott’s genes, with the majority returning to normal after six months on Earth. However, a small percentage of genes related to the immune system and DNA repair did not return to baseline after his return to Earth. Further, the results identified key genes to target for use in monitoring the health of future astronauts and potentially developing personalized countermeasures.

What We Learned: Immunome

Another key finding is that Scott’s immune system responded appropriately in space. For example, the flu vaccine administered in space worked exactly as it does on Earth. A fully functioning immune system during long-duration space missions is critical to protecting astronaut health from opportunistic microbes in the spacecraft environment.

What We Learned: Proteomics

Studying protein pathways in Scott enabled researchers to look at fluid regulation and fluid shifts within his body. Shifts in fluid may contribute to vision problems in astronauts. Scientists found a specific protein associated with fluid regulation was elevated in Scott, compared with his brother Mark on Earth.

What We Learned: Telomeres

The telomeres in Scott’s white blood cells, which are biomarkers of aging at the end of chromosomes, were unexpectedly longer in space then shorter after his return to Earth with average telomere length returning to normal six months later. In contrast, his brother’s telomeres remained stable throughout the entire period. Because telomeres are important for cellular genomic stability, additional studies on telomere dynamics are planned for future one-year missions to see whether results are repeatable for long-duration missions.

What We Learned: Cognition

Scott Kelly participated in a series of cognitive performance evaluations (such as mental alertness, spatial orientation, and recognition of emotions) administered through a battery of tests and surveys. Researchers found that during spaceflight, Scott’s cognitive function remained normal for the first half of his stay onboard the space station compared to the second half of his spaceflight and to his brother, Mark, on the ground. However, upon landing, Scott’s speed and accuracy decreased. Re-exposure to Earth’s gravity and the dynamic experience of landing may have affected the results.  

What We Learned: Biochemical

In studying various measurements on Scott, researchers found that his body mass decreased during flight, likely due to controlled nutrition and extensive exercise. While on his mission, Scott consumed about 30% less calories than researchers anticipated. An increase in his folate serum (vitamin B-9), likely due to an increase of the vitamin in his pre-packaged meals, was also noted by researchers. This is bolstered by the telomeres study, which suggests that proper nutrition and exercise help astronauts maintain health while in space.

What We Learned: Metabolomics

Within five months of being aboard the space station, researchers found an increase in the thickness of Scott’s arterial wall, which may have been caused by inflammation and oxidative stress during spaceflight. Whether this change is reversible is yet to be determined. They hope these results will help them understand the stresses that the human cardiovascular system undergoes during spaceflight. 

In addition, the results from the Microbiome, Epigenomics, and Integrative Omics studies suggest a human body is capable of adapting to and recovering from the spaceflight environment on a molecular level.

Why Does This Matter?

The data from the Twins Study Investigation will be explored for years to come as researchers report some interesting, surprising, and assuring data on how the human body is able to adapt to the extreme environment of spaceflight. This study gave us the first integrated molecular view into genetic changes, and demonstrated the plasticity and robustness of a human body!

We will use the valuable data to ensure the safety and health of the men and women who go on to missions to the Moon and on to Mars.

Learn more with this video about these fascinating discoveries!  

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Pick Your Favorite Findings From Fermi’s First Decade

The Fermi Gamma-ray Space Telescope has been observing some of the most extreme objects and events in the universe — from supermassive black holes to merging neutron stars and thunderstorms — for 10 years. Fermi studies the cosmos using gamma rays, the highest-energy form of light, and has discovered thousands of new phenomena for scientists.

Here are a few of our favorite Fermi discoveries, pick your favorite in the first round of our “Fermi Science Playoff.” 

Colliding Neutron Stars

In 2017, Fermi detected a gamma ray burst at nearly the same moment ground observatories detected gravitational waves from two merging neutron stars. This was the first time light and ripples in space-time were detected from the same source.

The Sun and Moon in Gamma Rays

In 2016, Fermi showed the Moon is brighter in gamma rays than the Sun. Because the Moon doesn’t have a magnetic field, the surface is constantly pelted from all directions by cosmic rays. These produce gamma rays when they run into other particles, causing a full-Moon gamma-ray glow.

Record Rare from a Blazar

The supermassive black hole at the center of the galaxy 3C 279 weighs a billion times the mass of our Sun. In June 2015, this blazar became the brightest gamma-ray source in the sky due to a record-setting flare.

The First Gamma-Ray Pulsar in Another Galaxy

In 2015, for the first time, Fermi discovered a gamma-ray pulsar, a kind of rapidly spinning superdense star, in a galaxy outside our own. The object, located on the outskirts of the Tarantula Nebula, also set the record for the most luminous gamma-ray pulsar we’ve seen so far.

A Gamma-Ray Cycle in Another Galaxy

Many galaxies, including our own, have black holes at their centers. In active galaxies, dust and gas fall into and “feed” the black hole, releasing light and heat. In 2015 for the first time, scientists using Fermi data found hints that a galaxy called PG 1553+113 has a years-long gamma-ray emission cycle. They’re not sure what causes this cycle, but one exciting possibility is that the galaxy has a second supermassive black hole that causes periodic changes in what the first is eating.

Gamma Rays from Novae

A nova is a fairly common, short-lived kind of explosion on the surface of a white dwarf, a type of compact star not much larger than Earth. In 2014, Fermi observed several novae and found that they almost always produce gamma-rays, giving scientists a new type of source to explore further with the telescope.

A Record-Setting Cosmic Blast

Gamma-ray bursts are the most luminous explosions in the universe. In 2013, Fermi spotted the brightest burst it’s seen so far in the constellation Leo. In the first three seconds alone, the burst, called GRB 130427A, was brighter than any other burst seen before it. This record has yet to be shattered.

Cosmic Rays from Supernova Leftovers

Cosmic rays are particles that travel across the cosmos at nearly the speed of light. They are hard to track back to their source because they veer off course every time they encounter a magnetic field. In 2013, Fermi showed that these particles reach their incredible speed in the shockwaves of supernova remains — a theory proposed in 1949 by the satellite’s namesake, the Italian-American physicist Enrico Fermi.

Discovery of a Transformer Pulsar

In 2013, the pulsar in a binary star system called AY Sextanis switched from radio emissions to high-energy gamma rays. Scientists think the change reflects erratic interaction between the two stars in the binary.

Gamma-Ray Measurement of a Gravitational Lens

A gravitational lens is a kind of natural cosmic telescope that occurs when a massive object in space bends and amplifies light from another, more distant object. In 2012, Fermi used gamma rays to observe a spiral galaxy 4.03 billion light-years away bending light coming from a source 4.35 billion light-years away.

New Limits on Dark Matter

We can directly observe only 20 percent of the matter in the universe. The rest is invisible to telescopes and is called dark matter — and we’re not quite sure what it is. In 2012, Fermi helped place new limits on the properties of dark matter, essentially narrowing the field of possible particles that can describe what dark matter is.

‘Superflares’ in the Crab Nebula

The Crab Nebula supernova remnant is one of the most-studied targets in the sky — we’ve been looking at it for almost a thousand years! In 2011, Fermi saw it erupt in a flare five times more powerful than any previously seen from the object. Scientists calculate the electrons in this eruption are 100 times more energetic than what we can achieve with particle accelerators on Earth.

Thunderstorms Hurling Antimatter into Space

Terrestrial gamma-ray flashes are created by thunderstorms. In 2011, Fermi scientists announced the satellite had detected beams of antimatter above thunderstorms, which they think are a byproduct of gamma-ray flashes.

Giant Gamma-Ray Bubbles in the Milky Way

Using data from Fermi in 2010, scientists discovered a pair of “bubbles” emerging from above and below the Milky Way. These enormous bubbles are half the length of the Milky Way and were probably created by our galaxy’s supermassive black hole only a few million years ago.

Hint of Starquakes in a Magnetar

Neutron stars have magnetic fields trillions of times stronger than Earth’s. Magnetars are neutron stars with magnetic fields 1,000 times stronger still. In 2009, Fermi saw a storm of gamma-ray bursts from a magnetar called SGR J1550-5418, which scientists think were related to seismic waves rippling across its surface.

A Dark Pulsar

We observe many pulsars using radio waves, visible light or X-rays. In 2008, Fermi found the first gamma-ray only pulsar in a supernova remnant called CTA 1. We think that the “beam” of gamma rays we see from CTA 1 is much wider than the beam of other types of light from that pulsar. Those other beams never sweep across our vision — only the gamma-rays.

Have a favorite Fermi discovery or want to learn more? Cast your vote in the first of four rounds of the Fermi Science Playoff to help rank Fermi’s findings. Or follow along as we celebrate the mission all year.

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