PHOENIX » Jared Loughner, his head shaved and a cut on his right temple, stared vacantly at a packed courtroom yesterday. About 100 miles away, the congresswoman he is accused of trying to assassinate lay gravely wounded but able to give a thumbs-up sign that doctors took as hope.

Loughner’s arrival in the federal courthouse in downtown Phoenix was the nation’s first look at the 22-year-old loner.

His hands cuffed, Loughner seemed impassive, a stark contrast to the man who witnesses say shot Rep. Gabrielle Giffords in the head at close range in a rampage that left six dead, including a federal judge, and injured 14 others at the three-term Democrat’s outdoor meeting with constituents in Tucson on Saturday.

At one point during his initial court hearing, Loughner stood at a lectern in his beige prison jumpsuit. The judge asked whether he understood that he could get life in prison — or the death penalty — for killing federal Judge John Roll.

"Yes," he said. His newly appointed lawyer, Judy Clarke, stood beside him. She had defended "Unabomber" Ted Kaczynski.

The judge ordered Loughner held without bail.

Throngs of reporters and television news crews lined up outside the federal courthouse, where the hearing was moved from Tucson. The entire federal bench there recused itself because Roll was the chief judge.

President Barack Obama will travel to Arizona tomorrow to attend a memorial service for the victims, a senior administration official said on the condition of anonymity because the president’s trip had not been publicly announced.

Earlier in the day, the nation observed a moment of silence for the victims, from the South Lawn of the White House and the steps of the U.S. Capitol to legislatures beyond Arizona and the planet itself.

At the International Space Station, Giffords’ brother-in-law, Scott, the commanding officer, spoke over the radio as flight controllers in Houston fell silent.

"As I look out the window, I see a very beautiful planet that seems very inviting and peaceful," he said. "Unfortunately, it is not.

"These days, we are constantly reminded of the unspeakable acts of violence and damage we can inflict upon one another, not just with our actions, but also with our irresponsible words," he said.

"We’re better than this," he said. "We must do better."

On a frigid morning outside the White House, Obama and first lady Michelle Obama stood side by side, each with their hands clasped, heads bowed and eyes closed. On the steps of the U.S. Capitol, congressional staff and other employees did the same.

At the Supreme Court, the justices paused for a moment of silence between the two cases they were hearing yesterday morning.

The president called for the country to come together in prayer or reflection for those killed and those fighting to recover.

In total, six died and 14 were injured or wounded outside a supermarket where Giffords set up a booth to hear the concerns of constituents.

Loughner was tackled to the ground minutes after the shooting began, authorities said.

Among the dead was 9-year-old Christina Taylor Green, who was born on the day of the Sept. 11, 2001, terrorist attacks. Her funeral is Thursday.

It was unclear when funerals will be held for the other victims. A Mass for all the victims was scheduled for today at St. Odelia’s Parish in Tucson.

Loughner is charged with one count of attempted assassination of a member of Congress, two counts of killing an employee of the federal government and two counts of attempting to kill a federal employee. Those are federal charges.

State prosecutors, meanwhile, are researching whether they have to wait until after the federal case is resolved or whether they can proceed with local charges at the same time, an official said.

Giffords, 40, was shot in the head, at close range. She was in critical condition at Tucson’s University Medical Center. Two patients were discharged Sunday night. Seven others remained hospitalized.

Recent CT scans showed no further swelling in the brain, but doctors were guarded.

"We’re not out of the woods yet," her neurosurgeon Dr. Michael Lemole said. "That swelling can sometimes take three days or five days to maximize. But every day that goes by and we don’t see an increase, we’re slightly more optimistic."

After Saturday’s operation to temporarily remove half of her skull, doctors had Giffords removed from her sedation over the past two days and then asked basic commands such as, "Show me two fingers."

"When she did that, we were having a party in there," said Dr. Peter Rhee, adding that Giffords has also managed to give doctors a thumbs-up and has been reaching for her breathing tube, even while sedated.

"That’s a purposeful movement. That’s a great thing," he said.

Her doctors have declined to speculate on what specific disabilities Giffords might face.