Space News & Blog Articles

In a recent paper submitted in November 2022, a scientist at the Swiss Federal Institute of Technology Lausanne quantifies how the Earth has not heard a radio signal from an extraterrestrial technological civilization over the course of approximately the last 60 years, which is when the Search for Extraterrestrial Intelligence (SETI) began listening for such signals. They also quantify the potential likelihood pertaining to when we might hear a signal, along with recommending potential strategies that could aid in the ongoing search for detecting a signal from an extraterrestrial technological civilization.

“One interesting result of this study is that it bridges the gap between two popular but opposing views,” Dr. Claudio Grimaldi, who is a guest scientist in the Laboratory of Statistical Biophysics at the Swiss Federal Institute of Technology Lausanne, and sole author of the study, recently told Universe Today. “One insists that technoemissions pervade our galaxy and that, persevering in the search, we will eventually find them, while the other argues that extraterrestrial technological life is so rare that can be considered practically nonexistent.

“Personally, if I had to choose, I would prefer the first option to the second. However, there could be a third, less extreme possibility that should be considered if we want to get a more complete picture. That is, since we began searching only about 60 years ago without success, then it is possible that Earth has not been illuminated by technosignals since then, even though other regions of the galaxy may have been. In other words, it could be that for at least 60 years the Earth has been inside a sort of ‘silent bubble’.”

Dr. Grimaldi’s results provide statistical assessments on when a radio signal might pass by the Earth, which he refers to as a “crossing event”, noting a 95% probability the next crossing event will not occur longer than 100,000 years, 50% probability of a crossing event occurring between no less than 60 to 1,800 years, and 20% probability of a crossing event occurring no sooner than 240 years.

“In the ‘silent bubble’ scenario, the waiting time of no less than 60 years is very optimistic,” Dr. Grimaldi recently told Universe Today. “Moreover, even after this time span, the fact that the Earth may be illuminated by technological signals is a necessary but not sufficient condition for their detection since they may be missed by our telescopes. Thus, even in the optimistic 60-year time window for a crossing event, the waiting time until detection could be much longer.”

In a recent study published in Sciences Advances, an international team of scientists led by the Technical University of Munich examined the Martian meteorite Tissint, which fell near the village of Tissint, Morocco, on July 18, 2011, with pieces of the meteorite found as far as approximately 50 kilometers (30 miles) from the village. What makes Tissint intriguing is the presence of a “huge organic diversity”, as noted in the study, which could help scientists better understand if life ever existed on Mars, and even the geologic history of Earth, as well.

“Mars and Earth share many aspects of their evolution,” Dr. Philippe Schmitt-Kopplin, who is the Director of the Research Unit Analytical Biochemistry at the Technical University of Munich, and lead author of the study, said in a statement. “And while life arose and thrived on our home planet, the question of whether it ever existed on Mars is a very hot research topic that requires deeper knowledge of our neighboring planet’s water, organic molecules, and reactive surfaces.” 

Organic molecules are molecules comprised of carbon atoms that are bonded to hydrogen atoms, but can also contain oxygen, nitrogen, and other elements, as well. The four primary classes of organic molecules include carbohydrates, proteins, nucleic acids, and lipids. As seen on Earth, organic molecules are analogous to life, but the study notes that abiotic organic chemistry, non-biological processes, have been observed “in other Martian meteorites.”

“Understanding the processes and sequence of events that shaped this rich organic bounty will reveal new details about Mars’ habitability and potentially about the reactions that could lead to the formation of life,” Dr. Andrew Steele, who is a Staff Science at Carnegie Science, a member of the Mars Sample Return Campaign Science Group for NASA’s Perseverance rover, and a co-author on the study, said in a statement. Dr. Steele has also conducted extensive research pertaining to organic material found in Martian meteorites, to include Tissint.

For the study, the researchers examined the entirety of Tissint’s organic composition, and identified a “diverse chemistry and abundance in complex molecules “, as noted in the study, while also helping to unlock the past geologic processes within the crust and mantle of the Red Planet. The researchers also identified a plethora of organic magnesium compounds never before observed on Mars, which could bring new evidence about the geochemical processes that shaped Mars’ deep interior while possibly making a link between the Red Planet’s mineral evolution and carbon cycle.

Here’s another striking image from the venerable Hubble Space Telescope. These billows of blue and red show a detailed look at a small portion of the famous Orion Nebula. But what really catches the eye are the brilliant stars with the cross-shaped diffraction spikes — a hallmark of Hubble images.

In the center is the bright variable star V 372 Orionis and a smaller companion star in the upper left is named BD-05 1307.

V 372 Orionis, also known as HD 36917 or Ori 47, is a so-called Orion variable — a variable star which exhibits irregular variations in its brightness. Orion variables are often associated with diffuse nebulae, just like the nebulous gas and dust of the Orion Nebula, a massive star-forming region full of young, hot stars that lies approximately 1,450 light-years from Earth.

BD-05 1307, otherwise known as 2MASS J05345223-0533085 or TIC 427373786, is classified as an emission-line star.

This image uses data from two of Hubble’s instruments. Data from the Advanced Camera for Surveys and Wide Field Camera 3 at infrared and visible wavelengths were layered to reveal rich details of this corner of the nebula, a frequent target of Hubble over the years.

Detecting exoplanets was frontier science not long ago. But now we’ve found over 5,000 of them, and we expect to find them around almost every star. The next step is to characterize these planets more fully in hopes of finding ones that might support life. Directly imaging them will be part of that effort.

But to do that, astronomers need to block out the light from the planets’ stars. That’s challenging in binary star systems.

When astronomers need to block out starlight in order to examine a nearby planet, they use a telescopic attachment called a coronagraph. The Hubble Space Telescope has one, and so do many other telescopes. They’re very effective.

Coronagraph effectiveness is well-established in single-star systems. But what about binary stars and multiple-star systems? Binary stars are common in the Milky Way, and up to 85% of Milky Way stars may be in binary systems. And they’re plentiful in our neighbourhood, too. The ESA’s Gaia spacecraft found 1.3 million binary stars within 1,000 light-years of Earth.

We don’t have to look far to find a multi-star system with exoplanets. Our nearest stellar neighbour, the Alpha Centauri system, is a triple-star system. Alpha Centauri A and B are both bright, Sun-like stars. The system’s third star, Proxima Centauri, is a small red dwarf only slightly larger than Jupiter. Proxima Centauri is so dim that Alpha Centauri is effectively more like a binary star. Alpha Centauri A and B are also close to one another, while Proxima Centauri is in a much wider orbit around the main pair.