Forty-five years ago this fall, our HEAO (High Energy Astronomy Observatory) 3 satellite blasted off to survey the high-energy sky. Its observations furthered our understanding of how the universe works and what it’s made of. Follow this thread for some highlights! 🧵 Launched from Cape Canaveral on Sept. 20, 1979, HEAO 3 (known as HEAO C before launch) was the last in a series of @NASA spacecraft designed to study X-rays, gamma rays, and cosmic rays from intriguing sources observed for the first time in the 1950s and 60s.

The Japanese-led XRISM (pronounced “crism”) telescope launched almost a year ago as part of a long collaboration between @JAXA_en and @NASA. XRISM focuses on the hottest regions, largest structures, and objects with the strongest gravity in the universe. go.nasa.gov/4d7BVk9
@JAXA_en @NASA From calcium in our bones to iron in our blood, we are made of star stuff. But how does the universe make and distribute these elements? XRISM studies the objects and events that created the cosmic recipe of our present-day universe.

Love a morally gray love interest? Black holes are a great example since they have the perfect air of mystery to get away with the dramatic relationships they maintain. From long-term love to one-sided situationships, black holes do it all. go.nasa.gov/46f0skR
Some supermassive black holes, ones that are millions to billions of times the mass of our Sun, are basically childhood sweethearts with the galaxies that form around them — like Sagittarius A* and our own Milky Way.

Did you know that black holes can be social? Let’s look at black holes that are scattered across our galaxy. Most of them have dance partners that can make them easier to detect. #BlackHoleWeek 🧵1/6 This dance starts before there’s a black hole in the picture. Most stars are born with at least one companion, and if either is large enough — 20+ times the Sun’s mass — it will explode as a supernova at the end of its life and leave a black hole. 2/6 science.nasa.gov/universe/the-l…

#OTD 15 years ago, our Kepler telescope launched to detect planets outside our solar system. Before it retired in 2018, it helped us find thousands of new worlds … and much more!

Follow this thread for a few of our favorite discoveries! 🧵 Kepler’s steady gaze helped it spot the subtle dimming of a star’s light when a planet passed between us and the star. And it also helped Kepler see a supernova shockwave as it reached the surface of a star — an early moment in an unpredictable event: jpl.nasa.gov/news/nasas-kep…

You’ve heard that you’re made of star stuff, but what does that mean? The chemical elements in our bodies — and everything else around us — were made in space billions of years ago, before our solar system formed. So where did some of your elements come from? #PeriodicTableDay The hydrogen that makes up the water in your body was formed during the big bang.

Our universe is speckled with stars, with billions just in our galaxy. Some stars live alone or in twos or threes, but others are bound together by gravity into much larger communities. In honor of @NASAHubble’s exploration of #StarrySights, let’s talk about star clusters! 🧵 1/6 Star clusters are divided into a few different types, based on how many stars are in a cluster and how tightly they’re bound by gravity. Stars in clusters typically have a shared origin, and they can live very close together or can be spread out over hundreds of light-years. 2/6

Are you enjoying our #BlackHoleFriday coverage? Like listening to podcasts? Then grab your headphones and dive into the black-hole-themed podcasts we’ve curated in this thread! 🎧 #BlackHoleFriday The Small Steps, Giant Leaps podcast interviewed Fiona Harrison, the NuSTAR PI, for the X-ray telescope’s 10th anniversary. She talks about its biggest black hole findings and other cool things we’ve learned over the past decade: go.nasa.gov/3u1B4wo #BlackHoleFriday

This week in 2008, our Fermi Gamma-ray Space Telescope launched. Since then it has been our eyes on the gamma-ray sky! Follow this thread for some science highlights, and read more about Fermi and gamma rays in this Tumblr post: tmblr.co/Zz_Uqj2TjyFug #FermiFriday Some of the universe’s brightest sources of light are black holes in the centers of galaxies! Black holes can turn galaxies into cosmic flashlights, and our Fermi telescope is helping us learn more about them: tmblr.co/Zz_Uqj2VhC7pa

Just because black holes don’t emit light doesn’t mean they’re totally invisible to us. By studying hints that point to their existence, we can learn a lot about them! Follow this thread and read more here: tmblr.co/Zz_UqjZ-7BiySm… #BlackHoleWeek⚫ 1/6 One thing black holes can’t hide is their gravity. They affect their environment just like anything else in the universe that has mass. 2/6

Want to get up to speed on black holes? We’ve got you covered! A black hole is an object so dense that not even light can escape it. #BlackHoleWeek⚫ 1/6 go.nasa.gov/3OOqRNd A black hole’s “surface” is its event horizon. Inside this boundary you’d have to go faster than light, the fastest thing in the universe, to escape the black hole. 2/6

Our Swift satellite just detected its 1,500th gamma-ray burst! 🛰💥 This powerful explosion was observed on Oct. 23 in the constellation Ursa Major. To celebrate, let’s explore 3 other extra-special Swift observations from over 16 years of science. 🥳 Soon after launch, Swift was the first to spy a short gamma-ray burst with an afterglow — GRB 050509B lasted only 0.03 seconds! ⏱ Other telescopes followed up to continue the hunt for the cause of these bursts, later confirmed to be neutron star mergers. go.nasa.gov/2ZruPGO

The Burst Alert Telescope, or BAT, on our Swift satellite just surpassed 1 million triggers! 🎉 The BAT constantly watches for gamma-ray bursts — powerful but fleeting explosions signaling a black hole’s birth. 💥 Get up to speed on gamma-ray bursts here: tmblr.co/Zz_Uqj2aNmOwb ☑️ The BAT’s onboard algorithms review each trigger to see if it’s a cosmic source or a statistical fluctuation. In sifting through those many triggers, Swift’s BAT has detected about 1,400 bona fide bursts along with a number of other notable discoveries.
👀 Let’s look at some.

#OTD in 2008, @NASA’s Fermi Gamma-ray Space Telescope began its science operations. In these 12 years, Fermi helps open our eyes to better understand some of the most powerful cosmic sources like these: On Aug 4, 2017, Fermi detected a powerful, short gamma-ray burst located 130 million light-years away. Those gamma rays had friends! @NSF’s LIGO also detected gravitational waves from this pair of colliding neutron stars. go.nasa.gov/31lcAzw

This week, the stars of Eta Carinae made their closest approach — about the distance between Mars & the Sun — to each other occurring every 5.5 years. As the most massive, radiant & unstable star system within 10,000 light-years, it could even be the next bright supernova. The larger of the two stars in Eta Carinae is a luminous blue variable about 90 times the mass of our Sun. Though rare now, we think these “superstars” were common in the early universe, when they were fundamental in forming the first black holes.