Space

This winter solstice, Dec. 21st, you'll be able to see something no one has seen since the Middle Ages; Jupiter and Saturn will appear so close together in Earth’s night sky they will look like a double planet. While we orbit the sun each year, Jupiter needs 12 and Saturn 30, which means every 20 years or so Jupiter laps Saturn, and on December 21st, 2020, the two planets will be just a tenth of a degree apart, less than the diameter of the moon. The two largest planets in our solar system will look to some like a double planet from science fiction.  A view showing how the Jupiter-…

Arecibo while no longer unique in design since China built a similar and larger telescope was special. What should replace it is something that will exceed what it is able to do. There is already a well formed plan for such a radio telescope using a properly chosen lunar crater. Taking an existing landform and using it for the dish reduces the work that needs to be done. Locating this hypothetical observatory on the Moon’s far side would shield it from most all man made radio noise. Combining data from a Moon based radio telescope with that from Earth based radio telescopes could result in…

Have you ever looked at the moon through a telescope, or even a pair of binoculars? Our satellite is really beautiful to look at - it is full of detail you can get lost in: craters, mountain ridges, canyons, plateaus. And there's no clouds to obscure the view (if you are a planetary observer and you put an eye on Mars a couple of years ago you know what I mean - a dust storm that went on for weeks completely hid the surface from outside observers).As a 7 years old, when I first set my eyes on the moon with a small 1.66" refractor telescope, I was totally awed by the sight, and even now, 47…

In a classic "Charlie Brown" Halloween tale, one character believes in the pumpkin equivalent of an Easter Bunny or Tooth Fairy, but NGC  2292 and NGC  2293 are real. At 109,000 light-years across, the diameter of our Milky Way, they don't just form a Great Pumpkin, they form the greatest pumpkin of all. What looks like two glowing eyes and a crooked carved smile is a snapshot of the early stages of a collision between the two galaxies. The "pumpkin’s" glowing "eyes" are the bright, star-filled cores of each galaxy that contain supermassive black holes.  If it seems to be smiling, thanks…

Like with kids, when it comes to galaxies adolescent blemishes disappear over time. Exponential disks, common in spiral galaxies, dwarf elliptical galaxies and some irregular galaxies, appear smooth and have an exponential fade. How did they get it way? It's not possible to know but using inference, simulations help provide insight.  Graohic showing how two sample star orbits are scattered from nearly circular orbits by the gravity of massive clumps within galaxies. Image: Illustration by Jian Wu/Iowa State University. Galaxy image from the Sloan Digital Sky Survey.…

Marco Fulvio Barozzi (b. 1955), a former Maths teacher and scientific blogger (https://keespopinga.blogspot.com), as well as a humorous poet, is a regular contributor to scientific and mathematics magazines. I read a very interesting piece he wrote on Phosphine, the substance recently discovered on the Venus atmosphere, and asked him if I could reproduce it here. He graciously agreed, so here it is below. Phosphine (phosphane according to IUPAC, or hydrogen phosphide or phosphorus trihydride) is the chemical compound with the brute formula PH3. Its structure vaguely resembles that of ammonia…

Dr Tommi Markkanen, an expert on the False Vacuum has kindly answered these questions in an email interview: 1. Does a false vacuum decay due to quantum tunneling have a realistic chance happening in my lifetime or already be on its way? The answer is a resounding ‘no’. I’m assuming the question is referring specifically to the Standard Model of particle physics for which the likelihood of such an event can be reliably estimated as all input parameters are known to high accuracy. The probability of vacuum decay as predicted by the Standard Model is so mindbogglingly small that in every…

(Inside Science) -- For the first time, an intact world may have been discovered around a white dwarf, suggesting that even after typical stars die, they may still host planets, a new study finds. White dwarfs are the cooling Earth-size cores of dead stars left behind after average-size stars have exhausted their fuel and shed their outer layers. Our sun will eventually fade into a white dwarf after first bloating to become a red giant. The same fate awaits more than 90% of the stars in our galaxy. Previous research has found the remains of worlds that disintegrated when the progenitor…

The Andromeda galaxy, our nearest large galactic neighbor, has been found to have a nearly invisible halo of diffuse plasma that extends about halfway to our Milky Way. That's 1.3 million light-years, and it may go 2 million light-years in some parts, which means Andromeda's halo is already touching our own. The halo has a layered structure, with two main nested and distinct shells of gas. These reservoirs of gas contain fuel for future star formation within the galaxy, as well as outflows from events such as supernovae.  If we could see it, the M31 halo would be about three times the…

The false vacuum collapse is about a remote possibility, not just billions of years in the future, so far in the future that all the stars in the night sky have run out of fuel, long before. There is no realistic possibility at present, or for billions of years, and it is of no concern. Text: Can’t be here (instability) Can’t realistically tunnel for billions of years even without new physics (meta-stability) May be here Could still be absolutely stable with present physics (Absolute stability) Many ways we may be here (lots of physics still to understand) (Absolute stability)…