1+ week, 5+ day ago   (373+ words) Researchers have completed one of the largest computer simulations of cosmic history yet assembled. Called ASTRID, it follows the growth of galaxies and black holes from the universe’s early days to the present, giving astronomers a virtual laboratory for testing…...

2+ week, 5+ day ago   (711+ words) They use a chain of methods rather than one universal measuring tape. Radar can reach planets. Parallax works for nearby stars. Farther out, astronomers compare known brightnesses, stellar pulsations and the stretching of light. Each step is checked against the…...

3+ week, 5+ day ago   (775+ words) Those signals are small. A transit can dim a star by less than one percent, while a star’s gravitational wobble may shift its spectral lines by only a few metres per second. Repeated measurements turn those tiny changes into evidence…...

1+ week, 4+ day ago   (461+ words) A telescope is often described as a device that makes distant objects look closer. That is true, but it leaves out the part that matters most to astronomers. The main purpose of a telescope is to collect light—sometimes light…...

2+ week, 1+ day ago   (583+ words) The signal is extraordinarily small. The star may be thousands or millions of times brighter than the planet, and the atmosphere is only a narrow rim around a moving world. Astronomers observe repeated transits, calibrate the telescope and compare the…...

2+ week, 5+ day ago   (656+ words) The Tarantula Nebula is one of the busiest stellar nurseries in our galactic neighbourhood. Thousands of young stars are packed into a web of gas and dust in the Large Magellanic Cloud, about 160,000 light-years away. Now three NASA space telescopes…...

1+ week, 2+ day ago   (752+ words) A parsec is a distance defined by parallax. Here is how astronomers use the unit to measure the space between stars and galaxies. What is a parsec? It is a unit of distance used by astronomers to describe the space…...

1+ week, 6+ day ago   (804+ words) Why do planets orbit the Sun instead of falling into it? The short answer is that gravity pulls the planets inward while their sideways motion carries them forward. The combination produces a curved path. A planet is always falling toward…...

1+ week, 5+ day ago   (821+ words) A quasar is a distant galaxy with a brilliant active centre. Here is how a feeding supermassive black hole can outshine every star around it. What is a quasar? The short answer is a distant galaxy with an extraordinarily bright…...

4+ week, 8+ hour ago   (565+ words) Most comets and asteroids that pass through the Solar System are permanent residents. The Sun’s gravity keeps them on closed orbits, even when those orbits take thousands of years to complete. An interstellar object is different. It arrives on a…...