Space and astronomy news
How much “stuff” is there in the Universe? You’d think it would be easy to figure out. But, it’s not. Astronomers add up what they can detect, and still find there’s more to the cosmos than they see. So, what’s “out there” and how do they account for it all?
Continue reading “A New Technique Confirms the Universe is 69% Dark Energy, 31% Matter (Mostly Dark)”
The Universe is big, as Douglas Adams would say.
The most distant light we can see is the cosmic microwave background (CMB), which has taken more than 13 billion years to reach us. This marks the edge of the observable universe, and while you might think that means the Universe is 26 billion light-years across, thanks to cosmic expansion it is now closer to 46 billion light-years across. By any measure, this is pretty darn big. But most cosmologists think the Universe is much larger than our observable corner of it. That what we can see is a small part of an unimaginably vast, if not infinite creation. However, a new paper argues that the observable universe is mostly all there is.
In other words, on a cosmic scale, the Universe is quite small.
Continue reading “The Case for a Small Universe”
Measuring cosmic distances is a major challenge thanks to the fact that we live in a relativistic Universe. When astronomers observe distant objects, they are not just looking through space but also back in time. In addition, the cosmos has been expanding ever since it was born in the Big Bang, and that expansion is accelerating. Astronomers typically rely on one of two methods to measure cosmic distances (known as the Cosmic Distance Ladder). On the one hand, astronomers rely on redshift measurements of the Cosmic Microwave Background (CMB) to determine cosmological distances.
Conversely, they will rely on local observations using parallax measurements, variable stars, and supernovae. Unfortunately, there is a discrepancy between redshift measurements of the CMB and local measurements, leading to what is known as the Hubble Tension. To address this, a team of astronomers from several Chinese universities and the University of Cordoba conducted a two-year statistical analysis of one million galaxies. From this, they’ve developed a new technique that relies on Baryon Acoustic Oscillations (BAO) to determine distances with a greater degree of precision.
Continue reading “Another New Way to Measure Distance in the Universe: Baryon Acoustic Oscillations”
Our best understanding of the Universe is rooted in a cosmological model known as LCDM. The CDM stands for Cold Dark Matter, where most of the matter in the universe isn’t stars and planets, but a strange form of matter that is dark and nearly invisible. The L, or Lambda, represents dark energy. It is the symbol used in the equations of general relativity to describe the Hubble parameter, or the rate of cosmic expansion. Although the LCDM model matches our observations incredibly well, it isn’t perfect. And the more data we gather on the early Universe, the less perfect it seems to be.
Continue reading “It's Going to Take More Than Early Dark Energy to Resolve the Hubble Tension”
In 1929 Edwin Hubble published the first solid evidence that the universe is expanding. Drawing upon data from Vesto Slipher and Henrietta Leavitt, Hubble demonstrated a correlation between galactic distance and redshift. The more distant a galaxy was, the more its light appeared shifted to the red end of the spectrum. We now know this is due to cosmic expansion. Space itself is expanding, which makes distant galaxies appear to recede away from us. The rate of this expansion is known as the Hubble parameter, and while we have a good idea of its value, there is still a bit of tension between different results.
Continue reading “A New Way to Measure the Expansion Rate of the Universe: Redshift Drift”
You’ve just found the perfect work desk at a garage sale, and you measure it to see if it will fit in your apartment. You brought a tape measure to size it up and find it’s 180 cm. Perfect. But your friend also brought a tape measure, and they find it’s 182 cm, which would be a smidge too long. You don’t know which tape measure is right, so you have a conundrum. Astronomers also have a conundrum, and it’s known as the Hubble tension.
Continue reading “JWST is the Perfect Machine to Resolve the Hubble Tension”
For astronomers, the only thing better than new data is more new data. And we seem to be in a golden age of data gathering. We’ve gushed over the latest images from the James Webb Space Telescope and Hubble continues to make observations, but several new space telescopes are lesser known, such as Gaia, TESS, and Swift. And now a new space telescope enters the game, known as Euclid. Euclid is an infrared telescope launched last month by the European Space Agency (ESA). It took 11 years to design and build the telescope, and it has just taken test images with its two primary detectors.
Continue reading “Euclid Reaches L2, Shares its First Test Image”
There’s an old joke among astronomy students about a question on the final exam for a cosmology class. It goes like this: “Describe the Universe and give three examples.” Well, a team of researchers in Germany, the U.S., and the UK took a giant leap toward giving at least one accurate example of the Universe.
Continue reading “An Enormous Cosmological Simulation Wraps Up, Recreating Even More of the Universe”
The more astronomers look at the early Universe, the more discoveries they make. Some of those finds change what they thought they knew about the infancy of the cosmos. For example, the James Webb Space Telescope (JWST) recently found evidence of carbon-based molecules and dust existing only a billion years after the Big Bang. It looks a bit different from the dust observed later in the Universe.
Continue reading “Carbon-Based Molecules Seen Just a Billion Years After the Big Bang”
When the James Webb Space Telescope started collecting data, it gave us an unprecedented view of the distant cosmos. Faint, redshifted galaxies seen by Hubble as mere smudges of light were revealed as objects of structure and form. And astronomers were faced with a bit of a problem. Those earliest galaxies seemed too developed and too large to have formed within the accepted timeline of the universe. This triggered a flurry of articles claiming boldly that JWST had disproven the big bang. Now a new article in the Monthly Notices of the Royal Astronomical Society argues that the problem isn’t that galaxies are too developed, but rather that the universe is twice as old as we’ve thought. A whopping 26.7 billion years old to be exact. It’s a bold claim, but does the data really support it?
Continue reading “The Universe Could Be Twice As Old if Light is Tired and Physical Constants Change”