{"id":10391,"date":"2024-03-11T12:03:51","date_gmt":"2024-03-11T16:03:51","guid":{"rendered":"https:\/\/zobi.alcowep.com\/bourtagshdrevxnls658739\/nasas-webb-hubble-telescopes-affirm-universes-expansion-rate-puzzle-persists\/"},"modified":"2024-03-11T12:03:51","modified_gmt":"2024-03-11T16:03:51","slug":"nasas-webb-hubble-telescopes-affirm-universes-expansion-rate-puzzle-persists","status":"publish","type":"post","link":"https:\/\/zobi.alcowep.com\/bourtagshdrevxnls658739\/nasas-webb-hubble-telescopes-affirm-universes-expansion-rate-puzzle-persists\/","title":{"rendered":"NASA\u2019s Webb, Hubble Telescopes Affirm Universe\u2019s Expansion Rate, Puzzle Persists"},"content":{"rendered":"

NASA\u2019s Webb, Hubble Telescopes Affirm Universe\u2019s Expansion Rate, Puzzle Persists<\/h2>\n

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6 min read<\/p>\n

NASA\u2019s Webb, Hubble Telescopes Affirm Universe\u2019s Expansion Rate, Puzzle Persists<\/h1>\n<\/div>\n<\/div>\n<\/div>\n

When you are trying to solve one of the biggest conundrums in cosmology, you should triple check your homework. The puzzle, called the \u201cHubble Tension,\u201d is that the current rate of the expansion of the universe is faster than what astronomers expect it to be, based on the universe\u2019s initial conditions and our present understanding of the universe\u2019s evolution.<\/p>\n

Scientists using NASA\u2019s Hubble Space Telescope<\/a> and many other telescopes consistently find a number that does not match predictions based on observations from ESA\u2019s (European Space Agency\u2019s) Planck<\/a> mission. Does resolving this discrepancy require new physics? Or is it a result of measurement errors between the two different methods used to determine the rate of expansion of space?<\/p>\n

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\"A<\/figure>
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This image of NGC 5468, a galaxy located about 130 million light-years from Earth, combines data from the Hubble and James Webb space telescopes. This is the farthest galaxy in which Hubble has identified Cepheid variable stars. These are important milepost markers for measuring the expansion rate of the universe. The distance calculated from Cepheids has been cross-correlated with a type Ia supernova in the galaxy. Type Ia supernovae are so bright they are used to measure cosmic distances far beyond the range of the Cepheids, extending measurements of the universe\u2019s expansion rate deeper into space.<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n
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Hubble has been measuring the current rate of the universe\u2019s expansion for 30 years, and astronomers want to eliminate any lingering doubt about its accuracy. Now, Hubble and NASA\u2019s James Webb Space Telescope<\/a> have tag-teamed to produce definitive measurements, furthering the case that something else \u2013 not measurement errors \u2013 is influencing the expansion rate.<\/p>\n

\u201cWith measurement errors negated, what remains is the real and exciting possibility we have misunderstood the universe,\u201d said Adam Riess, a physicist at Johns Hopkins University in Baltimore. Riess holds a Nobel Prize for co-discovering the fact that the universe\u2019s expansion is accelerating, due to a mysterious phenomenon now called \u201cdark energy.\u201d<\/p>\n

As a crosscheck, an initial Webb observation in 2023<\/a> confirmed that Hubble measurements of the expanding universe were accurate. However, hoping to relieve the Hubble Tension, some scientists speculated that unseen errors in the measurement may grow and become visible as we look deeper into the universe. In particular, stellar crowding could affect brightness measurements of more distant stars in a systematic way.<\/p>\n

The SH0ES (Supernova H0 for the Equation of State of Dark Energy) team, led by Riess, obtained additional observations with Webb of objects that are critical cosmic milepost markers, known as Cepheid variable stars<\/a>, which now can be correlated with the Hubble data.<\/p>\n

\u201cWe\u2019ve now spanned the whole range of what Hubble observed, and we can rule out a measurement error as the cause of the Hubble Tension with very high confidence,\u201d Riess said.<\/p>\n

The team\u2019s first few Webb observations in 2023 were successful in showing Hubble was on the right track in firmly establishing the fidelity of the first rungs of the so-called cosmic distance ladder<\/a>.<\/p>\n

Astronomers use various methods to measure relative distances in the universe, depending upon the object being observed. Collectively these techniques are known as the cosmic distance ladder \u2013 each rung or measurement technique relies upon the previous step for calibration.<\/p>\n

But some astronomers suggested that, moving outward along the \u201csecond rung,\u201d the cosmic distance ladder might get shaky if the Cepheid measurements become less accurate with distance. Such inaccuracies could occur because the light of a Cepheid could blend with that of an adjacent star \u2013 an effect that could become more pronounced with distance as stars crowd together and become harder to distinguish from one another.<\/p>\n

The observational challenge is that past Hubble images of these more distant Cepheid variables look more huddled and overlapping with neighboring stars at ever farther distances between us and their host galaxies, requiring careful accounting for this effect. Intervening dust further complicates the certainty of the measurements in visible light. Webb slices though the dust and naturally isolates the Cepheids from neighboring stars because its vision is sharper than Hubble\u2019s at infrared wavelengths.<\/p>\n

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\"A<\/figure>
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At the center of these side-by-side images is a special class of star used as a milepost marker for measuring the universe\u2019s rate of expansion \u2013 a Cepheid variable star. The two images are very pixelated because they are a very zoomed-in view of a distant galaxy. Each of the pixels represents one or more stars. The image from the James Webb Space Telescope is significantly sharper at near-infrared wavelengths than Hubble (which is primarily a visible-ultraviolet light telescope). By reducing the clutter with Webb\u2019s crisper vision, the Cepheid stands out more clearly, eliminating any potential confusion. Webb was used to look at a sample of Cepheids and confirmed the accuracy of the previous Hubble observations that are fundamental to precisely measuring the universe\u2019s expansion rate and age.<\/div>\n
NASA, ESA, CSA, STScI, Adam G. Riess (JHU, STScI)<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n
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\u201cCombining Webb and Hubble gives us the best of both worlds. We find that the Hubble measurements remain reliable as we climb farther along the cosmic distance ladder,\u201d said Riess.<\/p>\n

The new Webb observations<\/a> include five host galaxies of eight Type Ia supernovae containing a total of 1,000 Cepheids, and reach out to the farthest galaxy where Cepheids have been well measured \u2013 NGC 5468 \u2013 at a distance of 130 million light-years. \u201cThis spans the full range where we made measurements with Hubble. So, we\u2019ve gone to the end of the second rung of the cosmic distance ladder,\u201d said co-author Gagandeep Anand of the Space Telescope Science Institute in Baltimore, which operates the Webb and Hubble telescopes for NASA.<\/p>\n

Hubble and Webb\u2019s further confirmation of the Hubble Tension sets up other observatories to possibly settle the mystery. NASA\u2019s upcoming Nancy Grace Roman Space Telescope<\/a> will do wide celestial surveys to study the influence of dark energy, the mysterious energy that is causing the expansion of the universe to accelerate. ESA\u2019s Euclid<\/a> observatory, with NASA contributions, is pursuing a similar task.<\/p>\n

At present it\u2019s as though the distance ladder observed by Hubble and Webb has firmly set an anchor point on one shoreline of a river, and the afterglow of the big bang observed by Planck\u2019s measurement from the beginning of the universe is set firmly on the other side. How the universe\u2019s expansion was changing in the billions of years between these two endpoints has yet to be directly observed. \u201cWe need to find out if we are missing something on how to connect the beginning of the universe and the present day,\u201d said Riess.<\/p>\n

These finding were published in the February 6, 2024 issue of The Astrophysical Journal Letters<\/a>.<\/p>\n

The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA. NASA\u2019s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. Goddard also conducts mission operations with Lockheed Martin Space in Denver, Colorado. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble and Webb science operations for NASA.<\/p>\n

The James Webb Space Telescope is the world\u2019s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.<\/p>\n

More Webb News<\/a><\/u><\/strong>: https:\/\/science.nasa.gov\/mission\/webb\/latestnews\/<\/a><\/p>\n

More Hubble News<\/a><\/span>: <\/strong>https:\/\/science.nasa.gov\/mission\/hubble\/hubble-news\/<\/a><\/p>\n

More Webb Images<\/a><\/span><\/strong>: https:\/\/science.nasa.gov\/mission\/webb\/multimedia\/images\/<\/a><\/p>\n

More Hubble Images<\/a><\/span>:<\/strong> https:\/\/science.nasa.gov\/mission\/hubble\/multimedia\/hubble-images\/<\/a><\/p>\n

Webb Mission Page<\/a><\/u><\/strong>: https:\/\/science.nasa.gov\/mission\/webb\/<\/a><\/p>\n

Hubble Mission Page<\/a><\/span>:<\/strong> https:\/\/science.nasa.gov\/mission\/hubble\/<\/a><\/p>\n

Learn More<\/h1>\n
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\n\t\tHubble Reaches New Milestone in Mystery of Universe\u2019s Expansion Rate<\/span>
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\n\t\tMystery of the Universe\u2019s Expansion Rate Widens With New Hubble Data<\/span>
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\n\t\tNASA\u2019s Hubble Extends Stellar Tape Measure 10 Times Farther Into Space<\/span>
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\n\t\tDiscovering the Runaway Universe<\/span>
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Media Contacts<\/span>: <\/em><\/strong><\/p>\n

Claire Andreoli \u2013\u00a0claire.andreoli@nasa.gov<\/a>
Laura\u00a0Betz\u00a0\u2013\u00a0laura.e.betz@nasa.gov<\/a>
NASA\u2019s\u00a0Goddard Space Flight Center<\/a>,\u00a0Greenbelt, MD<\/strong><\/p>\n

Ray Villard, Christine Pulliam
Space Telescope Science Institute, Baltimore, MD<\/strong><\/p>\n

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