INFORMATION

How massive is the Milky Way? It’s an easy question to ask, but a difficult one to answer. Imagine a single cell in your body trying to determine your total mass, and you get an idea of how difficult it can be. Despite the challenges, a new study has calculated an accurate mass of our galaxy, and it’s smaller than we thought. One way to determine a galaxy’s mass is by looking at what’s known as its rotation curve . Measure the speed of stars in a galaxy versus their distance from the galactic center. The speed at which a star orbits is proportional to the amount of mass within its orbit, so from a galaxy’s rotation curve you can map the function of mass per radius and get a good idea of its total mass. We’ve measured the rotation curves for several nearby galaxies such as Andromeda, so we know the masses of many galaxies quite accurately. But since we are in the Milky Way itself, we don’t have a great view of stars throughout the galaxy. Toward the center of the galaxy, there is so ...

Since time immemorial, humans have gazed up at the stars and wondered if we’re alone in the universe. We have asked if there are other intelligent beings out there in the vastness of the cosmos, also known as extraterrestrial intelligence (ET). Yet, despite our best efforts , we have yet to confirm the existence of ET outside of the Earth. While the search continues, it’s fair to speculate if they might look “human” or humanoid in appearance, or if they could look like something else entirely. Here, we present a general examination and discussion with astrobiologists pertaining to what ET might look like and what environmental parameters (e.g., gravity, atmospheric makeup, stellar activity) might cause them to evolve differently than humans. “Some body plans may be more optimal than others, in the sense that they may be more streamlined, suitable for locomotion, etc,” Dr. Manasvi Lingam , who is an astrobiologist and Assistant Professor in the Department of Aerospace, Physics, and Sp...

It’s a basic fact we’ve all learned in school. Drop any object, be it a baseball, feather, or cat, and it will fall toward the Earth at exactly the same rate. The cat will fortunately land on its feet thanks to a bit of feline grace, but the point is that everything falls at the same rate under gravity. It doesn’t matter what an object is made of, or how heavy it is. While we’ve all been taught this fact, calling it a fact was, until recently, a bit of a lie. In physics, this fact is known as the equivalence principle , and it is the fundamental tenet of gravitational models. Galileo is rumored to have demonstrated it by dropping things off the Tower of Pisa, and astronauts demonstrated it by dropping hammers and feathers on the Moon. Every experiment we’ve done confirms the effect. So calling it a fact seems pretty reasonable. Except all of our experiments have only been done with objects made of matter. If we had baseball, feather, or cat made of antimatter, would they also fall d...

Exoplanet studies have come a long way in a short time! To date, 5,523 exoplanets have been confirmed in 4,117 systems, with another 9,867 candidates awaiting confirmation. With all these planets available for study, exoplanet researchers have been shifting their focus from detection to characterization – i.e., looking for potential signs of life and biological activity (biosignatures). Some major breakthroughs are expected in the coming years, thanks in part to next-generation observatories like NASA’s James Webb and Nancy Grace Roman Space Telescope and the ESA’s PLAnetary Transits and Oscillations of stars (PLATO) mission. Several ground-based facilities will also be vital to the characterization of exoplanets, like the Extremely Large Telescope (ELT), the Giant Magellan Telescope (GMT), and the Thirty Meter Telescope (TMT). But there are also existing observatories that could be upgraded to perform vital exoplanet research. This idea was explored in a recent paper by an int...

As the search for dark matter particles continues to yield nothing, astronomers continue to look at ways these elusive particles might be found. One general method is to look for evidence of dark matter particle decay. Although dark matter doesn’t interact strongly with regular matter, some dark matter models predict that dark matter particles can interact with each other, causing them to decay into regular particles . There have been several searches for this effect, but there’s no clear evidence yet. But a new study suggests looking at white dwarfs could be a good approach. White dwarfs are the dense remnants of dead stars . They have nearly a Sun’s worth of mass compressed into a sphere the size of Earth. White dwarfs are so dense it is the pressure of electrons that keeps them from collapsing. As the authors of this new study point out, white dwarfs have a perfect balance of being dense but not overly tiny like neutron stars. They are also very common throughout the Milky Way, gi...

There may come a day when we grow weary of JWST images. But it’s not today. Today, we can lose ourselves in the space telescope’s engrossing image of NGC 6822, also called Barnard’s Galaxy. Barnard’s Galaxy was discovered by the accomplished American astronomer E. E. Barnard in 1884. He spotted it with a 6-inch refractor telescope. It’s the closest galaxy to the Milky Way that isn’t a satellite galaxy, and it’s quite similar to our neighbour, the Small Magellanic Cloud. It’s a dwarf irregular galaxy about 7,000 light-years across and about 1.6 million light-years away. The JWST captured this image with its NIRCam instrument, and it shows the galaxy in deep detail. Dust and gas are pervasive in the galaxy, but the JWST has the power to see right through it with its infrared instruments. One of the reasons JWST was built was to peer through gas and dust and see what’s going on behind it. Zooming in reveals the JWST’s power. Here and there, distant galaxies pop into view well beyond ...

The upcoming solar eclipses and the current high sunspot activity means it’s a great time to observe the Sun. Eclipses also mean that large groups of people will be together to view these events. However, rule #1 for astronomy is to never look at the Sun with unprotected eyes, especially with a telescope or binoculars. So, how can you safely show the changing Sun to a large group of people without having them line up forever to look through a telescope with a solar filter, or having a lot of equipment? A group of astronomers have a solution: Get a disco ball. If you set up a disco ball in a sunlit room, they say, it will project tiny images of the Sun onto the walls, similar to how a pinhole camera works. But a disco ball can show the state of a solar eclipse or the presence of sunspots, and allow dozens of people to see it simultaneously. “Commercial disco balls provide a safe, effective and instructive way of observing the Sun,” a group of astronomers from several universities...

If we could wind the clock back billions of years, we’d see our Solar System the way it used to be. Planetesimals and other rocky bodies were constantly colliding with each other, and new objects would coalesce out of the debris. Asteroids rained down on the planets and their moons. The gas giants were migrating and contributing to the chaos by destroying gravitational relationships and creating new ones. Even moons and moonlets would’ve been part of the cascade of collisions and impacts. When nature crams enough objects into a small enough space, it breeds collisions. A new study says that’s what happened at Saturn and created the planet’s dramatic rings. The research is “ A Recent Impact Origin of Saturn’s Rings and Mid-sized Moons, ” and it’s published in The Astrophysical Journal.” The lead author is Luis Todorow, a Research Fellow at the School of Physics and Astronomy at the University of Glasgow. Saturn’s rings are so iconic that even schoolchildren can identify them. Astron...

Astronomers are working hard to understand biosignatures and how they indicate life’s presence on an exoplanet. But each planet we encounter is a unique puzzle. When it comes to planetary atmospheres, carbon is a big piece of the puzzle because it has a powerful effect on climate and biogeochemistry. If scientists can figure out how and where a planet’s carbon comes from and how it behaves in the atmosphere, they’ve made progress in solving the puzzle. But one of the problems with carbon in exoplanet atmospheres is that it can send mixed signals. Carbon, in this context, means all of the major species of carbon, things like carbon dioxide, carbon monoxide, and methane (CO2, CO, and CH4.) A new study investigates the diversity of these chemicals in the atmospheres of exoplanets similar to Earth orbiting stars similar to the Sun. The study is “ Relative abundances of CO2, CO, and CH4 in atmospheres of Earth-like lifeless planets. ” It’s been submitted to The Astrophysical Journal and...

In 1960, while preparing for the first meeting on the Search for Extraterrestrial Intelligence (SETI), legendary astronomer and SETI pioneer Dr. Frank Drake unveiled his probabilistic equation for estimating the number of possible civilizations in our galaxy – aka. The Drake Equation . A key parameter in this equation was n e , the number of planets in our galaxy capable of supporting life – aka. “habitable.” At the time, astronomers were not yet certain other stars had systems of planets. But thanks to missions like Kepler , 5523 exoplanets have been confirmed, and another 9,867 await confirmation! Based on this data, astronomers have produced various estimates for the number of habitable planets in our galaxy – at least 100 billion, according to one estimate! In a recent study , Professor Piero Madau introduced a mathematical framework for calculating the population of habitable planets within 100 parsecs (326 light-years) of our Sun. Assuming Earth and the Solar System are repres...