Astrophysics

The giant and the dwarf Astrophysics

The giant and the dwarf

Size alone is not always the most important factor. Sometimes, large things also orbit small things – because the details of a system matter. Astronomers have now found a real example for this situation in space, about 80 light-years from us, using the TESS telescope. The discovery published in Nature shows the likely presence of a planet the size of Jupiter orbiting the white dwarf, WD 1856+534, once every 34 hours. “This planet is roughly the size of Jupiter, but it also has a very short orbital period – one year on this planet is only 1.4 days long, so…
How the Magellanic Stream was formed Astrophysics

How the Magellanic Stream was formed

The Milky Way does not travel through the universe alone. It is accompanied on its journey by smaller galaxies. The two largest are the Small Magellanic Cloud and the Large Magellanic Cloud, which are both visible as dusty twin smudges in the southern hemisphere. When the Magellanic Clouds started orbiting the Milky Way billions of years ago (astronomers are not certain about the timing and the gravitational bond, it’s possible that they are still on their first approach to the Milky Way), an enormous stream of gas known as the Magellanic Stream was ripped out of them. The stream…
Is dark energy hidden in the husks of burned-out stars? Astrophysics

Is dark energy hidden in the husks of burned-out stars?

The idea that the expansion of the universe is accelerating is taken as fact today. The cause is a repulsive form of energy, dark energy. But its nature remains a mystery. Now, a team of researchers at the University of Hawai’i in Mānoa have made an interesting prediction in The Astrophysical Journal: dark energy, which is responsible for this accelerated growth, could originate from a giant sea of compact objects spread out in the cavities between galaxies. Since the mid-1960s, physicists have known that the collapse of stars might not produce true black holes, but instead so-called “GEneric Objects…
Milky Way vs. Andromeda: the collision has already begun Astrophysics

Milky Way vs. Andromeda: the collision has already begun

It’s inevitable that the Milky Way and the Andromeda Galaxy will one day collide and merge, even though right now there’s still 2.5 million light-years between them. Thus, the light that we see from Andromeda today was emitted from there 2.5 million years ago. The two most massive members of the Local Group are approaching each other at 120 kilometers per second. In three to four billion years (so while our Sun is still alive), up to 1.3 billion stars of the two galaxies will encounter each other. After another maybe three billion years, the merger will produce a…
Time travel in the quantum world: how to generate a self-healing reality Astrophysics

Time travel in the quantum world: how to generate a self-healing reality

The “butterfly effect” is a term from nonlinear dynamics, which is a subdomain of physics. It occurs in systems that meet three requirements: the output is not always proportional to the input (“nonlinear”), the progression is dependent on time, but is a function of only the original state (“dynamic”), and randomness is not a factor (“deterministic”: if A, then B). When these three conditions are met, a small change to the initial conditions can lead to large changes in the results. The phrase was coined by the meteorologist Edward Lorenz, who was referring to a butterfly flapping its wings…
This star system will never be the Solar System Astrophysics

This star system will never be the Solar System

TYC 8998-760-1 might someday become something like our Sun. Right now, however, the young star is still a few billion years away from that. It’s been around for only about 17 million years. If it were the Sun, there would still be a long time before it would even be able to watch the dinosaurs. Nevertheless, the whippersnapper is still something special: astronomers using the European Southern Observatory’s (ESO) Very Large Telescope (VLT) photographed it and found two planets in its orbit. “Even though astronomers have indirectly detected thousands of planets in our galaxy, only a tiny fraction of…
In the orbit of two giants Astrophysics

In the orbit of two giants

Eta Carinae, approximately 7500 light-years from Earth, has everything that an astronomer could want. First, there’s the nebula surrounding Eta Carinae. The so-called Homunculus Nebula is still growing. It has the shape of two opposing cones, whose tips originate in Eta Carinae, and measures more than 0.5 light-years from end to end. From the propagation rate of up to 700 km/s, the existence of the nebula can be traced back to an outburst in the 1840s. Second, it is not just a single star, but a binary system consisting of two blue giants. The primary star has a mass…
How does a star simply vanish? Astrophysics

How does a star simply vanish?

PHL 293B, also known as HL 293B, the Kinman dwarf galaxy, A2228-00, or SDSS J223036.79-000636.9, is a small, not especially bright galaxy 75 million light-years from the Sun. It belongs to a class of so-called “blue compact dwarf galaxies.” These normally consist of several large, young star clusters containing hot, massive stars. The brightest of these are blue – thus the designation of the galaxies and their color. PHL 293B is no different. Between 2001 and 2011, astronomers observed that the dwarf galaxy was dominated by a blue giant, a “luminous blue variable” (LBV), which shines approximately 2.5 million…