Universe Today

October 6, 2023October 6, 2023 by Evan Gough

One of the Brightest Stars in the Sky is Actually a Satellite

The bright streaks drawing an arc across the night sky are caused by the satellite BlueWalker 3. The prototype satellite is brighter than most stars. Image Credit: Ilse Plauchu-Frayn

Back in the 70s, kids used to look up at the summer sky and try to be the first one to shout, “Satellite!” That seems like a relic from the past now, alongside Polaroid cameras and astronauts on the Moon. These days, it’s rare to spend any amount of time looking at the sky without seeing a satellite, or several of them.

A new satellite is emphasizing that fact. It’s a prototype communications satellite with a roughly 700-square-foot antenna, and it’s brighter than most stars.

October 6, 2023October 6, 2023 by Brian Koberlein

What Caused Eta Carinae’s 1840 “Great Eruption?”

Hubble image of Eta Carinae. Credit: NASA, ESA, N. Smith (University of Arizona), and J. Morse (BoldlyGo Institute)

In 1840 an unassuming star in the Southern Hemisphere brightened suddenly. What had been a 5th magnitude star became so bright by 1843 that it was the second brightest star in the sky. The star, known as Eta Carinae, had been known to vary in brightness before, but this change was so sudden and so dramatic that it became known as the Great Eruption.

October 6, 2023October 6, 2023 by Andy Tomaswick

Could Modified Gravity Be the Answer to Planet 9?

As students advance to higher and higher physics courses, they eventually learn that the simple Newtonian dynamics they learned about in early classes aren’t completely accurate models for understanding the universe. If things get too big or fast, they fall into the realm of relativity, or if they get too small, they get caught up in quantum mechanics. However, simple Newtonian dynamics does the trick for things ranging from how a baseball flies to how planets orbit the Sun.

October 5, 2023October 5, 2023 by Carolyn Collins Petersen

Parker Makes its Closest and Fastest Solar Flyby

An artist's illustration of the Parker Solar Probe approaching the Sun. Image: NASA

The Parker Solar Probe is the little engine that just keeps going and going by the Sun. On September 27th, it made its 17th close approach and skimmed just 7.26 million kilometers (4.51 million miles) above the sun’s “surface” layer (called the photosphere).

October 5, 2023October 5, 2023 by Matt Williams

Those Impossibly Massive Early Galaxies Might Just Be Surprisingly Bright

Artist conception of starbursting galaxies in the early universe. Stars and galaxies are shown in the bright white points of light, while the more diffuse dark matter and gas are shown in purples and reds. Early gas clouds bounced past dark matter clumps, only to clump together again under dark matter's gravity -- sparking off star formation. Credit: Aaron M. Geller/Northwestern/CIERA + IT-RCDS

On July 12th, 2022, in an event live-streamed from the NASA Goddard Spaceflight Center, the James Webb Space Telescope’s (JWST) first images were released! Among them was the most detailed image of SMACS 0723, showing galaxy clusters and the gravitational lenses they produced. These lenses allowed astronomers to see deeper into the cosmos and spot galaxies as they appeared less than one billion years after the Big Bang (ca. 13 billion years ago). Upon further examination, however, they noticed something rather surprising about these early galaxies: they were much larger than expected!

According to the standard model of cosmology, the earliest galaxies in the Universe did not have enough time to become as bright, massive, and mature as they appeared. This raised many questions about our cosmological models and whether or not the Universe was older than previously thought. According to new simulations by a Northwestern University-led team of astrophysicists, these galaxies may not be so massive after all. According to their findings, they appear larger due to irregular and very bright bursts of star formation.

October 5, 2023October 5, 2023 by Scott Alan Johnston

Can JWST Tell the Difference Between an Exo-Earth and an Exo-Venus?

Earth and Venus. Why are they so different and what do the differences tell us about rocky exoplanet habitability? Image Credit: NASA

As of this month, astronomers have discovered 5,506 exoplanets orbiting other stars. That number is growing daily, and astronomers are hoping, among other things, to find Earth-like worlds. But will we know one when we see it? How might we be able to tell an Earth-like garden from a Venus-like pressure cooker from upwards of 40 light years away? Is JWST up to the challenge?

October 5, 2023October 5, 2023 by Evan Gough

Europa and Enceladus are the Perfect Targets for a Lightsail Mission

Saturn's moon Enceladus isn't just bright and beautiful. It has an ocean under all that ice that could have hydrothermal vents that create organic chemicals. Image Credit: NASA, ESA, JPL, SSI, Cassini Imaging Team

There’s always a need for new technologies or for novel uses of existing technologies to lower the cost of space exploration and extend our reach. Lightsails are a novel type of spacecraft that could eventually be our first visitors to nearby stars like the Alpha Centauri system. But they could be put to productive use right here in our Solar System.

October 5, 2023October 5, 2023 by Carolyn Collins Petersen

A Star Threw Off a Sun’s Worth of Material. And Then it Exploded!

Artist's conception of SN 2023ixf. One of the nearest Type II supernovae in a decade and among the brightest to date, SN 2023ixf is a young supernova. Its progenitor star exploded and the supernova was discovered earlier this year by amateur astronomer K?ichi Itagaki of Yamagata, Japan. Credit: Melissa Weiss/CfA

What happens just before a massive star explodes as a supernova? To figure that out, astronomers need to look at very “young” supernovae across multiple wavelengths of light. That’s what happened when SN 2023ixf occurred in May 2023. It turns out its aging progenitor star blew off a solar mass worth of material just before it died. Now, the big question is: why?

October 5, 2023October 8, 2023 by Matt Williams

Magnetic Fusion Plasma Engines Could Carry us Across the Solar System and Into Interstellar Space

A new study offers a new means of propulsion that could revolutionize space travel - the Magnetic Fusion Plasma Drive (MFPD). Credit: Created with Imagine

Missions to the Moon, missions to Mars, robotic explorers to the outer Solar System, a mission to the nearest star, and maybe even a spacecraft to catch up to interstellar objects passing through our system. If you think this sounds like a description of the coming age of space exploration, then you’d be correct! At this moment, there are multiple plans and proposals for missions that will send astronauts and/or probes to all of these destinations to conduct some of the most lucrative scientific research ever performed. Naturally, these mission profiles raise all kinds of challenges, not the least of which is propulsion.

Simply put, humanity is reaching the limits of what conventional (chemical) propulsion can do. To send missions to Mars and other deep space destinations, advanced propulsion technologies are required that offer high acceleration (delta-v), specific impulse (I_sp), and fuel efficiency. In a recent paper, Leiden Professor Florian Neukart proposes how future missions could rely on a novel propulsion concept known as the Magnetic Fusion Plasma Drive (MFPD). This device combines aspects of different propulsion methods to create a system that offers high energy density and fuel efficiency significantly greater than conventional methods.

October 5, 2023October 5, 2023 by Brian Koberlein

Will Solar Panels Work at Proxima Centauri?

The range of stars that might have habitable worlds. Credit: Schopp, et al

Solar panel technology has advanced significantly in recent years, to the point where solar energy is the fastest-growing renewable power source. The solar panels we have today are a by-product of those used in space. If you want to power a satellite or crewed spacecraft, there are only two ways: solar energy or nuclear power. Of the two, only solar energy isn’t limited by the amount of fuel you bring on board. As we contemplate traveling to other star systems, this raises the question: will solar panels work near other stars?