Sloan Digital Sky Survey Releases New Map Of Supermassive Black Holes

August 26, 2026 by Maya Posch 2 Comments

The Universe is a large place, yet despite it being mostly empty space, there are still a lot of things to find and catalogue. This includes mildly terrifying things like supermassive black holes (SMBHs), one of the study subjects of the Sloan Digital Sky Survey (SDSS) project. In their 20th data release of the fifth all-sky survey (SDSS-V), the results of the Black Hole Mapper (BHM) program provides a lot of new insights into these SMBHs.

For a good primer on the SDSS’s ongoing survey, you can read this paper by [Kollmeier] et al. from 2017 in which this fifth survey and its three programs, including the BHM, are explained. This comes after four previous phases of the SDSS, all of them focusing on multispectral imaging and spectroscopic redshift survey with the 2.5 m Apache Point Observatory (APO) in New Mexico.

With SDSS-V a second 2.5 m observatory at Las Campanas (LCO) was added, with both observatories combined able to observe the entire sky, not just as static images, but also any changes over time. While these observations are in the near-infrared, combined with the data from other observatories this gives us probably one of the most comprehensive maps of the Milky Way and everything therein, including black holes.

This 20th data release gives us one of the clearest glimpses yet at the formation, growth and behavior of SMBHs and similar objects over time. A big part of this achievement are the automatic positioning robots at the observatories that handle the fiber optics that feed spectrographs, enabling faster and more accurate observations.

Hackaday Links: June 8, 2025

June 8, 2025 by Dan Maloney 21 Comments

When purchasing high-end gear, it’s not uncommon for manufacturers to include a little swag in the box. It makes the customer feel a bit better about the amount of money that just left their wallet, and it’s a great way for the manufacturer to build some brand loyalty and perhaps even get their logo out into the public. What’s not expected, though, is for the swag to be the only thing in the box. That’s what a Redditor reported after a recent purchase of an Nvidia GeForce RTX 5090, a GPU that lists for $1,999 but is so in-demand that it’s unobtainium at anything south of $2,600. When the factory-sealed box was opened, the Redditor found it stuffed with two cheap backpacks instead of the card. To add insult to injury, the bags didn’t even sport an Nvidia logo.

The purchase was made at a Micro Center in Santa Clara, California, and an investigation by the store revealed 31 other cards had been similarly tampered with, although no word on what they contained in lieu of the intended hardware. The fact that the boxes were apparently sealed at the factory with authentic anti-tamper tape seems to suggest the substitutions happened very high in the supply chain, possibly even at the end of the assembly line. It’s a little hard to imagine how a factory worker was able to smuggle 32 high-end graphics cards out of the building, so maybe the crime occurred lower down in the supply chain by someone with access to factory seals. Either way, the thief or thieves ended up with almost $100,000 worth of hardware, and with that kind of incentive, this kind of thing will likely happen again. Keep your wits about you when you make a purchase like this.

Continue reading “Hackaday Links: June 8, 2025” →

The Hardware pipeline consists of three parts: antenna, signal conditioners, and computer. The solid lines indicate LMR-400 cable (low loss microwave coax), whereas the dotted line represents USB 3.0. (Credit: Jack Phelps)

Tracking Hydrogen In Space With A Home Radio Telescope For 21 Cm Emissions

November 5, 2024 by Maya Posch 7 Comments

What do you get when you put a one-meter parabolic dish, an SDR, a Raspberry Pi, and an H1-LNA for 21 cm emissions together? The answer is: a radio telescope that can track hydrogen in the Milky Way as well as the velocities of hydrogen clouds via their Doppler shifts, according to a paper by [Jack Phelps] titled “Galactic Neutral Hydrogen Structures Spectroscopy and Kinematics: Designing a Home Radio Telescope for 21 cm Emission“.

The hardware pipeline consists of three parts: antenna, signal conditioners, and computer, as per the above graphic by [Jack Phelps]. The solid lines are low-loss microwave coax LMR-400 cable, and the dotted line represents USB 3.0 between the RTL-SDR and Raspberry Pi 4 system. This Raspberry Pi 4 runs a pre-made OS image (NsfSdr) by [Dr. Glenn Langston] at the National Science Foundation, which contains scripts for hydrogen line observation, calibration and data processing.

After calibration, the findings were verified using publicly available data, and the setup could be used to detect hydrogen by pointing the antenna at the intended target in space. Although a one-meter parabolic dish isn’t going to give you the most sensitivity, it’s still pretty rad that using effectively all off-the-shelf components and freely available software, you too can have your own radio telescope.

Hackaday Links: May 15, 2022

May 15, 2022 by Dan Maloney 7 Comments

It may be blurry and blotchy, but it’s ours. The first images of the supermassive black hole at the center of the Milky Way galaxy were revealed this week, and they caused quite a stir. You may recall the first images of the supermassive black hole at the center of the M87 galaxy from a couple of years ago: spectacular images that captured exactly what all the theories said a black hole should look like, or more precisely, what the accretion disk and event horizon should look like, since black holes themselves aren’t much to look at. That black hole, dubbed M87*, is over 55 million light-years away, but is so huge and so active that it was relatively easy to image. The black hole at the center of our own galaxy, Sagittarius A*, is comparatively tiny — its event horizon would fit inside the orbit of Mercury — a much closer at only 26,000 light-years or so. But, our black hole is much less active and obscured by dust, so imaging it was far more difficult. It’s a stunning technical achievement, and the images are certainly worth checking out.

Another one from the “Why didn’t I think of that?” files — contactless haptic feedback using the mouth is now a thing. This comes from the Future Interfaces Group at Carnegie-Mellon and is intended to provide an alternative to what ends up being about the only practical haptic device for VR and AR applications — vibrations from off-balance motors. Instead, this uses an array of ultrasonic transducers positioned on a VR visor and directed at the user’s mouth. By properly driving the array, pressure waves can be directed at the lips, teeth, and tongue of the wearer, providing feedback for in-world events. The mock game demonstrated in the video below is a little creepy — not sure how many people enjoyed the feeling of cobwebs brushing against the face or the splatter of spider guts in the mouth. Still, it’s a pretty cool idea, and we’d like to see how far it can go.

Continue reading “Hackaday Links: May 15, 2022” →

A Milky Way Photo Twelve Years In The Making

March 20, 2021 by Zach Zeman 22 Comments

Starting projects is easy. It’s the finishing part that many of us have trouble with. We can hardly imagine completing a project after more than a decade, but seeing the breathtaking results of [J-P Metsavainio]’s gigapixel composite image of our galaxy might just make us reconsider. The photograph, which we highly suggest you go check out in its full glory, has been in progress since 2009, features 1250 total hours of exposure time, and spans across 125 degrees of sky. It is simply spectacular.

Of course, it wasn’t an absolutely continuous effort to make this one image over those twelve years. Part of the reason for the extended time span is many frames of the mosaic were shot, processed, and released as their own individual pieces; each of the many astronomical features impressive in its own right. But, over the years, he’s filled in the gaps between and has been able to release a more and more complete picture of our galactic home.

A project this long, somewhat predictably, eventually outlives the technology used to create it. Up until 2014, [Metsavainio]’s setup included a Meade 12-inch telescope and some modified Canon optics. Since then, he’s used a dedicated equatorial mount, astrocamera, and a Tokina lens (again, modified) with an 11-inch Celestron for longer focal lengths. He processes the frames in Photoshop, accounting for small exposure and color differences and aligning the images based on background stars. He’s had plenty of time to get his process down, though, so the necessary tweaking is relatively minor.

Amateur astronomy is an awesome hobby, and the barrier to entry is lower than it might seem. You can get started on a budget with the ubiquitous Raspberry Pi or with the slightly less practical Game Boy Camera. And if you’re just interested in viewing the cosmos, there are options for building your own telescope as well.

[via PetaPixel]

Cecilia Payne-Gaposchkin Saw Through The Stars

December 15, 2020 by Kristina Panos 6 Comments

We as humans are limited in the ways we can look at things ourselves, and rely on on the different perspectives and insights of others to help make sense of things. All it takes is one person to look at a data set and find something completely different that changes our fundamental perception of the universe.

Cecilia Payne-Gaposchkin discovered that stars are primarily made of hydrogen and helium, at a time when astronomers thought that the Sun and the Earth had no significant elemental differences. She proposed that hydrogen wasn’t only more common, but that it was a million times more common.

This outlandish conclusion was roundly dismissed at the time, and she aquiesced to tone down some of the conclusions in her thesis, until her findings were widely confirmed a few years later. Truly groundbreaking, the discovery of the prevalence of hydrogen in stars paved the way for our current understanding of their role as the furnaces for the heavier elements that we know and love, and indeed are composed of.

Meteorites, Comets, and Bee Orchids

Cecilia Helena Payne was born May 10th, 1900 in Wendover, Buckinghamshire, England. She was one of three children born to Emma and Edward, a lawyer, historian, and musician. Her father died with she was four years old, leaving her mother to raise the family alone. Continue reading “Cecilia Payne-Gaposchkin Saw Through The Stars” →

Andrea Ghez Gazes Into Our Galaxy’s Black Hole

October 13, 2020 by Kristina Panos 21 Comments

Decades ago, Einstein predicted the existence of something he didn’t believe in — black holes. Ever since then, people have been trying to get a glimpse of these collapsed stars that represent the limits of our understanding of physics.

For the last 25 years, Andrea Ghez has had her sights set on the black hole at the center of our galaxy known as Sagittarius A*, trying to conclusively prove it exists. In the early days, her proposal was dismissed entirely. Then she started getting lauded for it. Andrea earned a MacArthur Fellowship in 2008. In 2012, she was the first woman to receive the Crafoord Prize from the Royal Swedish Academy of Sciences.

Now Andrea has become the fourth woman ever to receive a Nobel Prize in Physics for her discovery. She shares the prize with Roger Penrose and Reinhard Genzel for discoveries relating to black holes. UCLA posted her gracious reaction to becoming a Nobel Laureate.

A Star is Born

Andrea Mia Ghez was born June 16th, 1965 in New York City, but grew up in the Hyde Park area of Chicago. Her love of astronomy was launched right along with Apollo program. Once she saw the moon landing, she told her parents that she wanted to be the first female astronaut. They bought her a telescope, and she’s had her eye on the stars ever since. Now Andrea visits the Keck telescopes — the world’s largest — six times a year.

Andrea was always interested in math and science growing up, and could usually be found asking big questions about the universe. She earned a BS from MIT in 1987 and a PhD from Caltech in 1992. While she was still in graduate school, she made a major discovery concerning star formation — that most stars are born with companion star. After graduating from Caltech, Andrea became a professor of physics and astronomy at UCLA so she could get access to the Keck telescope in Mauna Kea, Hawaii.

The Keck telescopes and the Milky Way. Image via Flickr

The Center of the Galaxy

Since 1995, Andrea has pointed the Keck telescopes toward the center of our galaxy, some 25,000 light years away. There’s a lot of gas and dust clouding the view, so she and her team had to get creative with something called adaptive optics. This method works by deforming the telescope’s mirror in real time in order to overcome fluctuations in the atmosphere.

Thanks to adaptive optics, Andrea and her team were able to capture images that were 10-30 times clearer than what was previously possible. By studying the orbits of stars that hang out near the center, she was able to determine that a supermassive black hole with four millions times the mass of the sun must lie there. Thanks to this telescope hack, Andrea and other scientists will be able to study the effects of black holes on gravity and galaxies right here at home. You can watch her explain her work briefly in the video after the break. Congratulations, Dr. Ghez, and here’s to another 25 years of fruitful research.