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Category: space

In the local (redshift z ≈ 0) Universe, collisional ring galaxies make up only ~0.01% of galaxies1 and are formed by head-on galactic collisions that trigger radially propagating density waves2,3,4. These striking systems provide key snapshots for dissecting galactic disks and are studied extensively in the local Universe5,6,7,8,9. However, not much is known about distant (z 0.1) collisional rings10,11,12,13,14. Here we present a detailed study of a ring galaxy at a look-back time of 10.8 Gyr (z = 2.19). Compared with our Milky Way, this galaxy has a similar stellar mass, but has a stellar half-light radius that is 1.5–2.2 times larger and is forming stars 50 times faster. The extended, diffuse stellar light outside the star-forming ring, combined with a radial velocity on the ring and an intruder galaxy nearby, provides evidence for this galaxy hosting a collisional ring. If the ring is secularly evolved15,16, the implied large bar in a giant disk would be inconsistent with the current understanding of the earliest formation of barred spirals17,18,19,20,21. Contrary to previous predictions10,11,12, this work suggests that massive collisional rings were as rare 11 Gyr ago as they are today. Our discovery offers a unique pathway for studying density waves in young galaxies, as well as constraining the cosmic evolution of spiral disks and galaxy groups.

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The existence of a planet the size of Earth around the closest star to the Sun, Proxima Centauri, has been confirmed by an international team of scientists including researchers from the University of Geneva (UNIGE). The results, published in Astronomy & Astrophysics, reveal that the planet in question, Proxima b, has a mass of 1.17 Earth masses and is located in the habitable zone of its star, which it orbits in 11.2 days.

This breakthrough was possible thanks to radial velocity measurements of unprecedented precision using ESPRESSO, the Swiss-manufactured spectrograph, the most accurate currently in operation, which is installed on the Very Large Telescope in Chile. Proxima b was first detected four years ago by means of an older spectrograph, HARPS, also developed by the Geneva-based team, which measured a low disturbance in the star’s speed, suggesting the presence of a companion.

The ESPRESSO spectrograph has performed radial velocity measurements on the star Proxima Centauri, which is only 4.2 light-years from the sun, with an accuracy of 30 centimetres a second (cm/s), about three times more precision than that obtained with HARPS, the same type of instrument but from the previous generation.

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China’s space program will launch a Mars mission in July, according to its current plans. This will include deploying an orbital probe to study the red planet, and a robotic, remotely-controlled rover for surface exploration. The U.S. has also been planning another robotic rover mission for Mars, and it’s set to take off this summer, too – peak time for an optimal transit from Earth to Mars thanks to their relative orbits around the Sun.

This will be the first rover mission to Mars for China’s space program, and is one of the many ways that it’s aiming to better compete with NASA’s space exploration efforts. NASA has flown four previous Mars rover missions, and its fifth, with an updated rover called ‘Perseverance,’ is set to take place this years with a goal of making a rendezvous with Mars sometime in February 2021.

NASA’s mission also includes an ambitious rock sample return plan, which will include the first powered spacecraft launch from the red planet to bring that back. The U.S. space agency is also sending the first atmospheric aerial vehicle to Mars on this mission, a helicopter drone that will be used for short flights to collect additional data from above the planet’s surface.

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The formation of the Sun, the Solar System and the subsequent emergence of life on Earth may be a consequence of a collision between our galaxy, the Milky Way, and a smaller galaxy called Sagittarius, discovered in the 1990s to be orbiting our galactic home.

Astronomers have known that Sagittarius repeatedly smashes through the Milky Way’s disc, as its orbit around the galaxy’s core tightens as a result of gravitational forces. Previous studies suggested that Sagittarius, a so called dwarf galaxy, had had a profound effect on how stars move in the Milky Way. Some even claim that the 10 000 times more massive Milky Way’s trademark spiral structure might be a result of the at least three known crashes with Sagittarius over the past six billion years.

A new study, based on data gathered by ESA’s galaxy mapping powerhouse Gaia, revealed for the first time that the influence of Sagittarius on the Milky Way may be even more substantial. The ripples caused by the collisions seem to have triggered major star formation episodes, one of which roughly coincided with the time of the formation of the Sun some 4.7 billion years ago.

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At the agency’s Jet Propulsion Laboratory, team members are building the Coronagraph Instrument for the spacecraft and contributing to the mission’s science goals.

NASA is naming its next-generation space telescope currently under development, the Wide Field Infrared Survey Telescope (WFIRST), in honor of Nancy Grace Roman, NASA’s first chief astronomer, who paved the way for space telescopes focused on the broader universe.

The newly named Nancy Grace Roman Space Telescope – or Roman Space Telescope, for short – is set to launch in the mid-2020s. It will investigate long-standing astronomical mysteries, such as the force behind the universe’s expansion, and search for distant planets beyond our solar system.

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