A central aspect of galactic evolution is that they must eat or be eaten. Dark energy strives to push galaxies apart, but gravity tries to pull them together. As a result, galaxies tend to form into local groups. As these superclusters of galaxies become more isolated due to cosmic expansion, they gravitationally turn on each other, and in time the largest galaxies of the group will consume the smaller ones. The Milky Way is one of the larger galaxies in our local group, and so it has consumed smaller galaxies in the past. But piecing together the history of these galactic meals is a real challenge.
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In 1866 the American astronomer Daniel Kirkwood was studying all the known asteroids, which at the time amounted to several hundred. If you just look at a snapshot of the solar system, there’s nothing that particularly stands out about the asteroids. They appear to have all sorts of random positions and random orbits within the main asteroid belt, which sits halfway between Mars and Jupiter.
To date, a total of 4,884 extrasolar planets have been confirmed in 3,659 systems, with another 8,414 additional candidates awaiting confirmation. In the course of studying these new worlds, astronomers have noted something very interesting about the “rocky” planets. Since Earth is rocky and the only known planet where life can exist, astronomers are naturally curious about this particular type of planet. Interestingly, most of the rocky planets discovered so far have been many times the size and mass of Earth.
It’s almost impossible to comprehend a supernova explosion’s violent, destructive power. An exploding supernova can outshine its host galaxy for a few weeks or even months. That seems almost impossible when considering that a galaxy can contain hundreds of billions of stars. Any planet too close to a supernova would be completely sterilized by all the energy released, its atmosphere would be stripped away, and it may even be shredded into pieces.
On November 16th, 1974, a coded radio message was broadcast from the Arecibo Observatory in Puerto Rico. The message contained information on mathematics, humanity, the Solar System, DNA, and the Observatory itself. The destination for this message was Messier 13 (NGC 6205 or “The Great Hercules Cluster”), a globular star cluster located about 25,000 light-years from Earth in the constellation of Hercules.
If you thought landing a used rocket booster on a barge or a landing pad was crazy idea, take a look at how SpaceX plans to land the big Starship rocket.
Earth has had a long and complex history since its formation roughly 4.5 billion years ago. Initially, it was a molten ball, but eventually, it cooled and became differentiated. The Moon formed from a collision between Earth and a protoplanet named Theia (probably), the oceans formed, and at some point in time, about 4 billion years ago, simple life appeared.
70% of astronauts who spend time on the International Space Station (ISS) experience swelling at the back of their eyes, causing blurriness and impaired eyesight both in space and when they return to Earth. Sometimes, it’s permanent. Understanding the way microgravity affects the eyes, and the human body as a whole is an essential part of preparations for future long-duration spaceflights to the Moon and Mars. In an effort to understand the cause of these eye problems, researchers at the Medical University of South Carolina used MRI scans of twelve ISS astronauts to measure the intracranial venous system (veins that circulate blood to the brain) before and after flight. They’ve determined that there is a strong connection between the swelling of these veins and the onset of eye trouble.
Let’s not sugarcoat it. Exploring the Moon is not for the faint of heart! It’s an airless body, which means there is no atmosphere, the surface temperatures are extreme, and there’s lots of radiation. The low gravity also means you can never really walk on the surface and have to bounce around in a bulky spacesuit until you fall over. And you can bet your bottom dollar people will make a supercut of the footage someday (see below). Then there’s that awful moondust (aka. lunar regolith), which is electrostatically charged and sticks to EVERYTHING!
The James Webb Space Telescope primary mirror is now fully unfolded, which successfully completes the mission’s major deployments. The starboard side of the primary mirror was released into place today, completing a two-week long, complex deployment sequence. The mirror of the most powerful space telescope ever built is now open to prepare to “unfold the Universe.”
Most Universe Today readers are familiar with nebulae. They’re gaseous structures lit up with radiation from nearby stars, and they’re some of nature’s most beautiful forms.
The ESO has released some stunning new images of Orion’s Flame Nebula. They’re from a few years ago but are newly processed as part of the Orion cloud complex study. The images have led to discoveries in the often-observed Orion cloud complex.
Back in early December 2021, China’s Yutu 2 rover made headlines when it spied what looked like a curious cube-shaped object on the Moon’s surface. Of course, speculations ran rampant. And it didn’t help matters any when the China National Space Administration (CNSA) nicknamed the object the “mystery hut.”
As the James Webb Space Telescope unfolds and makes its way to its final destination in space, NASA and ESA have done a great job of sharing the experience with the public. With webcasts, livestreams and a very active social media presence, the JWST team has allowed people to watch over the shoulders of engineers and scientists, as well as ask questions about the process of commissioning the new telescope.
Green is an unusual color in astronomy. It is the color to which our eyes are most sensitive, and yet few things in the night sky actually appear green. There are, for example, no green stars, only yellow-white, red, and blue ones. But there can be green comets, and we are still learning why.
The Small Magellanic Cloud (SMC) is over 200,000 light-years away, yet it’s still one of our galaxy’s closest neighbours in space. Ancient astronomers knew of it, and modern astronomers have studied it intensely. But the SMC still holds secrets.
Roughly 13.8 billion years ago, our Universe was born in a massive explosion that gave rise to the first subatomic particles and the laws of physics as we know them. About 370,000 years later, hydrogen had formed, the building block of stars, which fuse hydrogen and helium in their interiors to create all the heavier elements. While hydrogen remains the most pervasive element in the Universe, it can be difficult to detect individual clouds of hydrogen gas in the interstellar medium (ISM).
Remember how China’s Tianwen-1 spacecraft released a remote camera to take a picture of itself during its flight to Mars, back in late 2020? Now in Mars orbit, Tianwen-1 has done it again, releasing another mini remote camera. Except this time, the planet Mars is part of the view.
The field of extrasolar planet studies continues to reveal some truly amazing things about our Universe. After decades of having just a handful of exoplanets available for study, astronomers are now working with a total of 4,884 confirmed exoplanets and another 8,288 awaiting confirmation. This number is expected to increase exponentially in the coming years as next-generation missions like the James Webb Space Telescope (JWST), Euclid, PLATO, and the Nancy Grace Roman Space Telescope (RST) reveal tens of thousands more.