One Exciting way to Find Planets: Detect the Signals From Their Magnetospheres

Artistic rendering of the Tau Bo├Âtes b system, showing the planet and its magnetic field. Credit: Jack Madden/Cornell University

We have discovered thousands of exoplanets in recent years. Most have them have been discovered by the transit method, where an optical telescope measures the brightness of a star over time. If the star dips very slightly in brightness, it could indicate that a planet has passed in front of it, blocking some of the light. The transit method is a powerful tool, but it has limitations. Not the least of which is that the planet must pass between us and its star for us to detect it. The transit method also relies on optical telescopes. But a new method could allow astronomers to detect exoplanets using radio telescopes.

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Hot Stars Blast Away at gas Giants Until Only Their Rocky Cores Remain

Artist view of a Neptune-sized planet orbiting a blue A-type star. Credit: Steven Giacalone, UC Berkeley

In our solar system, we have two types of planets. Small, warm, rocky worlds populate the inner region, while the outer region has cold gas giants. Intuitively this makes a lot of sense. When the solar system was forming, the Sun’s light and heat must have pushed much of the gas toward the outer system, leaving heavier dust and rock to form the inner worlds. Giants could only grow in the cold, dark outer solar system. But we now know our solar system is more the exception than the rule. Many star systems have large gas planets that orbit close to their stars. These hot Jupiters and hot Neptunes are unlike anything in our solar system, and astronomers are keen to understand what they may be like.

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Primordial Black Holes Could Have Triggered the Formation of Supermassive Black Holes

Artist view of merging black holes in the early universe. Credit: LIGO/Caltech/MIT/R. Hurt (IPAC)

The early moments of the universe were turbulent and filled with hot and dense matter. Fluctuations in the early universe could have been great enough that stellar-mass pockets of matter collapsed under their own weight to create primordial black holes. Although we’ve never detected these small black holes, they could have played a vital role in cosmic evolution, perhaps growing into the supermassive black holes we see today. A new study shows how this could work, but also finds the process is complicated.

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Thanks to Gaia we Know Exactly how and When the Sun Will die

How different types of stars live and die. Credit: ESA

Our Sun is doomed. Billions of years from now, the Sun will deplete its hydrogen fuel and swell to a red giant before becoming a white dwarf. It’s a well-known story, and one astronomers have understood for decades. Now, thanks to the latest data from Gaia, we know the Sun’s future in much greater detail.

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Even a Cyclical Universe Needed to Come From Somewhere

Could our Universe be part of a wider Multiverse? And could these other Universes support life? Credit: Jaime Salcido/EAGLE Collaboration

In the beginning…

The first words of the book of Genesis make a declarative statement. God created Heaven and Earth, and thus begins the cosmic story. While not all creation myths have an act of beginning, most do. Humans are storytellers, and we like stories with a beginning. This origin need is deep within us and is even part of our scientific worldview. As is so often said in science, effects have causes. This cause and effect process is a powerful tool for understanding the world around us, but it’s not without its problems, particularly with the origin of the universe.

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Astronomers Measure the Signal of Dark Matter From 12 Billion Years ago

Visualization of how dark matter lenses distant light. Credit: Reiko Matsushita (Nagoya University)

Although the particles of dark matter continue to allude us, astronomers continue to find evidence of it. In a recent study, they have seen its effect from the edge of visible space, when the universe was just 1.5 billion years old.

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Planet 9 is Running out of Places to Hide

Illustration of the hypothetical Planet 9. Credit: R. Hurt/IPAC, Caltech

We have a pretty good idea of what lurks within our solar system. We know there isn’t a Mars-sized planet orbiting between Jupiter and Saturn, nor a brown dwarf nemesis heading our way. Anything large and fairly close to the Sun would be easily spotted. But we can’t rule out a smaller, more distant world, such as the hypothetical Planet 9 (or Planet 10 if you want to throw down over Pluto). The odds against such a planet existing are fairly high, and a recent study finds it even less likely.

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When Stars eat Their Planets, the Carnage can be Seen Billions of Years Later

Artist view of a large planet soon to be devoured by its star. Credit: NASA, ESA, and G. Bacon (STScI). Science Credit: NASA, ESA, and C. Haswell (The Open University, UK)

The vast majority of stars have planets. We know that from observations of exoplanetary systems. We also know some stars don’t have planets, and perhaps they never had planets. This raises an interesting question. Suppose we see an old star that has no planets. How do we know if ever did? Maybe the star lost its planets during a close approach by another star, or maybe the planets spiraled inward and were consumed like Chronos eating his children. How could we possibly tell? A recent study on the arXiv answers half that question.

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A Fast-Moving Star is Colliding With Interstellar gas, Creating a Spectacular bow Shock

A multi-wavelength view of Zeta Ophiuchi. Credit: X-ray: NASA/CXC/Dublin Inst. Advanced Studies/S. Green et al.; Infrared: NASA/JPL/Spitzer

Zeta Ophiuchi has had an interesting life. It began as a typical large star about twenty times more massive than the Sun. It spent its days happily orbiting a large companion star until its companion exploded as a supernova about a million years ago. The explosion ejected Zeta Ophiuchi, so now it is speeding away through interstellar space. Of course, the supernova also expelled the outer layers of the companion star, so rather than empty space, our plucky star is speeding through the remnant gas as well. As they say on Facebook, it’s complicated. And that’s great news for astronomers, as a recent study shows.

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Gamma-ray Bursts can Help Astronomers Measure Vast Distances Across the Universe

An illustration of a powerful gamma ray burst. Credit: NAOJ

Now that the James Webb Space Telescope is operational, astronomers can study some of the most faint and distant galaxies ever seen. By some accounts, we may have already captured the image of a galaxy from when the universe was just 300 million years old. But we can’t be entirely sure of its distance, and that is a big problem for astronomers.

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