esa Archives

August 29, 2024August 31, 2024 by Matt Williams

Remember those Impossible Galaxies Found by JWST? It Turns Out They Were Possible After All

This is a small portion of the field observed by NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) for the Cosmic Evolution Early Release Science (CEERS) survey. It is filled with galaxies. The light from some of them has traveled for over 13 billion years to reach the telescope. Credit: NASA, ESA, CSA, Steve Finkelstein (University of Texas at Austin)

When the James Webb Space Telescope provided astronomers with a glimpse of the earliest galaxies in the Universe, there was some understandable confusion. Given that these galaxies existed during “Cosmic Dawn,” less than one billion years after the Big Bang, they seemed “impossibly large” for their age. According to the most widely accepted cosmological model—the Lambda Cold Dark Matter (LCDM) model—the first galaxies in the Universe did not have enough time to become so massive and should have been more modestly sized.

This presented astronomers with another “crisis in cosmology,” suggesting that the predominant model about the origins and evolution of the Universe was wrong. However, according to a new study by an international team of astronomers, these galaxies are not so “impossibly large” after all, and what we saw may have been the result of an optical illusion. In short, the presence of black holes in some of these early galaxies made them appear much brighter and larger than they actually were. This is good news for astronomers and cosmologists who like the LCDM the way it is!

August 29, 2024August 29, 2024 by Matt Williams

Webb Discovers Six New “Rogue Worlds” that Provide Clues to Star Formation

This stunning new mosaic of images from the NASA/ESA/CSA James Webb Space Telescope showcases the nearby star-forming cluster, NGC 1333. Credit: ESA/Webb, NASA & CSA, A. Scholz, K. Muzic, A. Langeveld, R. Jayawardhana

Rogue Planets, or free-floating planetary-mass objects (FFPMOs), are planet-sized objects that either formed in interstellar space or were part of a planetary system before gravitational perturbations kicked them out. Since they were first observed in 2000, astronomers have detected hundreds of candidates that are untethered to any particular star and float through the interstellar medium (ISM) of our galaxy. In fact, some scientists estimate that there could be as many as 2 trillion rogue planets (or more!) wandering through the Milky Way alone.

In recent news, a team of astronomers working with the James Webb Space Telescope (JWST) announced the discovery of six rogue planet candidates in an unlikely spot. The planets, which include the lightest rogue planet ever identified (with a debris disk around it), were spotted during Webb‘s deepest survey of the young nebula NGC 1333, a star-forming cluster about a thousand light-years away in the Perseus constellation. These planets could teach astronomers a great deal about the formation process of stars and planets.

August 27, 2024August 27, 2024 by Matt Williams

Massive Stars Shine in This Ultraviolet View From Hubble

NGC 346 is nestled within the Small Magellanic Cloud, a small satellite galaxy to our Milky Way. Credit: NASA/ESA/STScI/ Gladys Kober

Just outside the Milky Way Galaxy, roughly 210,000 light-years from Earth, there is the dwarf galaxy known as the Small Magellanic Cloud (SMC). Measuring about 18,900 light-years in diameter and containing roughly 3 billion stars, the SMC and its counterpart – the Large Magellanic Cloud (LMC) – orbit the Milky Way as satellite galaxies. Scientists are particularly interested in these satellites because of what they can teach us about star formation and the process where galaxies evolve through mergers, which is something the Milky Way will do with these two galaxies someday.

Another interesting feature of the SMC is the spectacular star cluster known as NGC 346, located near the center of the brightest star-forming region in the SMC, the hydrogen-rich nebula designated N66. Yesterday, NASA released a new image of this star cluster acquired by the venerable Hubble Space Telescope, which provides a unique and breathtaking view of this star cluster. These images were made possible thanks to Hubble’s sharp resolution and unique ability to make sensitive ultraviolet observations.

August 21, 2024August 21, 2024 by Matt Williams

Debris from DART could Hit Earth and Mars Within a Decade

The asteroid Dimorphos was captured by NASA’s DART mission just two seconds before the spacecraft struck its surface on Sept. 26, 2022. Observations of the asteroid before and after impact suggest it is a loosely packed “rubble pile” object. Credit: NASA/JHUAPL

On Sept. 26th, 2022, NASA’s Double Asteroids Redirect Test (DART) collided with Dimorphos, the small moonlet orbiting the larger asteroid Didymos. In so doing, the mission successfully demonstrated a proposed strategy for deflecting potentially hazardous asteroids (PHAs) – the kinetic impact method. By October 2026, the ESA’s Hera mission will rendezvous with the double-asteroid system and perform a detailed post-impact survey of Dimorphos to ensure that this method of planetary defense can be repeated in the future.

However, while the kinetic method could successfully deflect asteroids so they don’t threaten Earth, it could also create debris that might reach Earth and other celestial bodies. In a recent study, an international team of scientists explored how this impact test also presents an opportunity to observe how this debris could someday reach Earth and Mars as meteors. After conducting a series of dynamic simulations, they concluded that the asteroid ejecta could reach Mars and the Earth-Moon system within a decade.

August 16, 2024August 16, 2024 by David Dickinson

See JUICE Next Week During Its Earth-Moon Flyby

Well-placed observers have a rare opportunity to see an interplanetary spacecraft early next week.

If skies are clear, dedicated observers and imagers have a shot early next week at seeing a spacecraft headed to Jupiter.

The Mission is JUICE, the European Space Agency’s Jupiter Icy Moons Explorer. Launched atop an Ariane-5 rocket from Kourou Space Center in French Guiana on April 14^th, 2023, JUICE is due to arrive at Jupiter in 2031. But first, the spacecraft will perform several planetary flybys to pick up speed, hurdling it towards the outer solar system.

July 19, 2024July 19, 2024 by Matt Williams

Gaia Hit by a Micrometeoroid AND Caught in a Solar Storm

Artist impression of ESA's Gaia satellite observing the Milky Way. The background image of the sky is compiled from data from more than 1.8 billion stars. It shows the total brightness and colour of stars observed by Gaia — Artist impression of ESA's Gaia satellite observing the Milky Way (Credit : ESA/ATG medialab; Milky Way: ESA/Gaia/DPAC)

For over ten years, the ESA’s Gaia Observatory has monitored the proper motion, luminosity, temperature, and composition of over a billion stars throughout our Milky Way galaxy and beyond. This data will be used to construct the largest and most precise 3D map of the cosmos ever made and provide insight into the origins, structure, and evolutionary history of our galaxy. Unfortunately, this sophisticated astrometry telescope is positioned at the Sun-Earth L2 Lagrange Point, far beyond the protection of Earth’s atmosphere and magnetosphere.

As a result, Gaia has experienced two major hazards in recent months that could endanger the mission. These included a micrometeoroid impact in April that disrupted some of Gaia‘s very sensitive sensors. This was followed by a solar storm in May—the strongest in 20 years—that caused electrical problems for the mission. These two incidents could threaten Gaia‘s ability to continue mapping stars, planets, comets, asteroids, quasars, and other objects in the Universe until its planned completion date of 2025.

July 18, 2024July 18, 2024 by Matt Williams

ESA is Building a Mission to Visit Asteroid Apophis, Joining it for its 2029 Earth Flyby

ESA's Ramses mission to asteroid Apophis. Credit: ESA

According to the ESA’s Near-Earth Objects Coordination Center (NEOCC), 35,264 known asteroids regularly cross the orbit of Earth and the other inner planets. Of these, 1,626 have been identified as Potentially Hazardous Asteroids (PHAs), meaning that they may someday pass close enough to Earth to be caught by its gravity and impact its surface. While planetary defense has always been a concern, the comet Shoemaker-Levy 9 slamming into Jupiter in 1994 sparked intense interest in this field.

In 2022, NASA’s Double-Asteroid Redirect Test (DART) mission successfully tested the kinetic impact method when it collided with Dimorphos, the small asteroid orbiting Didymos. Today, the ESA Space Safety program is taking steps to test the next planetary defense mission – the Rapid Apophis Missin for Space Safety (RAMSES). In 2029, RAMSES will rendezvous with the Near Earth Asteroid (NEA) 99942 Apophis and accompany it as it makes a very close (but safe) flyby of Earth in 2029. The data it collects will help scientists improve our ability to protect Earth from similar objects that could pose an impact risk.

July 16, 2024July 16, 2024 by Matt Williams

New Images From Webb Reveal Jupiter's Complex Atmosphere

New observations of the Great Red Spot on Jupiter have revealed that the planet’s atmosphere above and around the infamous storm is surprisingly interesting and active. Credit: ESA

The James Webb Space Telescope (JWST) has accomplished some spectacular feats since it began operations in 2021. Thanks to its sensitivity in the near- and mid-infrared wavelengths, it can take detailed images of cooler objects and reveal things that would otherwise go unnoticed. This includes the iconic image Webb took of Jupiter in August 2022, which showed the planet’s atmospheric features (including its polar aurorae and Great Red Spot) in a new light. Using Webb, a team of European astronomers recently observed the region above the Great Red Spot and discovered previously unseen features.

June 15, 2024June 15, 2024 by Matt Williams

Don't Get Your Hopes Up for Finding Liquid Water on Mars

In the coming decades, NASA and China intend to send the first crewed missions to Mars. Given the distance involved and the time it takes to make a single transit (six to nine months), opportunities for resupply missions will be few and far between. As a result, astronauts and taikonauts will be forced to rely on local resources to meet their basic needs – a process known as in-situ resource utilization (ISRU). For this reason, NASA and other space agencies have spent decades scouting for accessible sources of liquid water.

Finding this water is essential for future missions and scientific efforts to learn more about Mars’s past, when the planet was covered by oceans, rivers, and lakes that may have supported life. In 2018, using ground-penetrating radar, the ESA’s Mars Express orbiter detected bright radar reflections beneath the southern polar ice cap that were interpreted as a lake. However, a team of Cornell researchers recently conducted a series of simulations that suggest there may be another reason for these bright patches that do not include the presence of water.

June 13, 2024June 13, 2024 by Matt Williams

NASA is Considering Other Ways of Getting its Mars Samples Home

Artist's impression of the NASA-ESA Mars Sample Return mission. Credit: NASA

In 2021, NASA’s Perseverance rover landed in the Jezero Crater on Mars. For the next three years, this astrobiology mission collected soil and rock samples from the crater floor for eventual return to Earth. The analysis of these samples is expected to reveal much about Mars’ past and how it transitioned from being a warmer, wetter place to the frigid and desiccated place we know today. Unfortunately, budget cuts have placed the future of the proposed NASA-ESA Mars Sample Return (MSR) mission in doubt.

As a result, NASA recently announced that it was seeking proposals for more cost-effective and rapid methods of bringing the samples home. This will consist of three studies by NASA and the Johns Hopkins University Applied Physics Laboratory (JHUAPL). In addition, NASA has selected seven commercial partners for firm-fixed-price contracts for up to $1.5 million to conduct their own 90-day studies. Once complete, NASA will consider which proposals to integrate into the MSR mission architecture.